- +44 131 455 3812
Emilio Pagani-Núñez
Edinburgh Napier University, School of Applied Sciences, Faculty Member
- Ecology, Evolution, Wildlife Biology, Ornithology, Urban Ecology, Sexual Selection, and 27 moreSpeciation, Evolutionary ecology (Ecology), Social Behaviour, Plumage Coloration, Invasive species ecology, Spiders, Trophic Ecology, Carotenoids, Longitudinal data analysis, Great Tits, Nestlings, Moult, Pigment Based Ornaments, Cross Sectional Analysis, Climate Change, Conservation Biology, Biodiversity, Marine Ecology, Behavioral Ecology, Evolutionary Biology, Zoology, Evolutionary Ecology, Animal Behavior, Invasive Species, Mate Choice, Birds (Ecology), and Stable Isotope Analysisedit
- I am a field ornithologist with broad interests in Ecology, Evolution and Behaviour. My research spans from individua... moreI am a field ornithologist with broad interests in Ecology, Evolution and Behaviour. My research spans from individuals to species and communities. Lately, I’m becoming increasingly interested in the impact that human activities have on the ecology of wild species and in investigating ways in which these impacts can be minimized. My last two projects investigate the impact that habitat transformation has on niches of passerine communities and on the breeding ecology of Barn Swallows.edit
Agricultural intensification not only increases food production but also drives widespread biodiversity decline. Increasing landscape heterogeneity has been suggested to increase biodiversity across habitats, while increasing crop... more
Agricultural intensification not only increases food production but also drives widespread biodiversity decline. Increasing landscape heterogeneity has been suggested to increase biodiversity across habitats, while increasing crop heterogeneity may support biodiversity within agroecosystems. These spatial heterogeneity effects can be partitioned into compositional (land-cover type diversity) and configurational heterogeneity (land-cover type arrangement), measured either for the crop mosaic or across the landscape for both crops and semi-natural habitats. However, studies have reported mixed responses of biodiversity to increases in these heterogeneity components across taxa and contexts. Our meta-analysis covering 6397 fields across 122 studies conducted in Asia, Europe, North and South America reveals consistently positive effects of crop and landscape heterogeneity, as well as compositional and configurational heterogeneity for plant, invertebrate, vertebrate, pollinator and predator biodiversity. Vertebrates and plants benefit more from landscape heterogeneity, while invertebrates derive similar benefits from both crop and landscape heterogeneity. Pollinators benefit more from configurational heterogeneity, but predators favour compositional heterogeneity. These positive effects are consistent for invertebrates and vertebrates in both tropical/subtropical and temperate agroecosystems, and in annual and perennial cropping systems, and at small to large spatial scales. Our results suggest that promoting increased landscape heterogeneity by diversifying crops and semi-natural habitats, as suggested in the current UN Decade on Ecosystem Restoration, is key for restoring biodiversity in agricultural landscapes.
Research Interests:
Parasitic infections have the potential to impact the hosts’ body condition, elevate physiological responses, and ultimately lead to increased mortality. Host-parasite interactions are tied to the ecological and life-history traits of the... more
Parasitic infections have the potential to impact the hosts’ body condition, elevate physiological responses, and ultimately lead to increased mortality. Host-parasite interactions are tied to the ecological and life-history traits of the hosts. While montane birds are susceptible to avian blood parasites, few studies have simultaneously assessed how inter- and intra-specific traits of hosts influence their probability of parasite infection. In this study, we screened for avian blood parasites across 214 individuals from 51 species at two sites, including a lowland farmland at 700 m and a highland forest at 2,500 m, in the Gaoligong Mountains in southwestern China. Overall blood parasite prevalence was 53.74%, with divergent species-specific prevalence ranging from 6.25% to 66.67%. We also measured traits indicative of body condition and physiological responses of each sampled individual. Using Bayesian phylogenetic logistic models, we assessed whether parasite infection probability is associated with ecological and life history traits of host species. Larger bird species were more likely to be infected than smaller bird species, and omnivore species showed lower susceptibility than those with other diets such as insectivores and herbivores. In contrast, foraging strata, nest type, and participation in mixed-species flocks of host species did not affect infection probability. We then used a reduced sample of eight species with more than five individuals, to assess the associations between intra-specific infection probability and host body condition, represented by fat and muscle reserves, and acute stress responses measured through breath rate. While infected individuals were likely to have more fat reserves than non-infected individuals, we did not find any association between infection probability and muscle reserve and body mass, nor with breath rate. Our results revealed that at the species level, specific traits (body mass and diet) of host species predict infection probability and implied a potential link at the individual level between enhanced body condition and increased resilience to parasite infection.
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The Kunming-Montreal Global Biodiversity Framework requires effective actions to bend the curve of biodiversity loss by 2030. Wildlife trade, a direct drive of biodiversity decline, calls for more effective regulations to both protect... more
The Kunming-Montreal Global Biodiversity Framework requires effective actions to bend the curve of biodiversity loss by 2030. Wildlife trade, a direct drive of biodiversity decline, calls for more effective regulations to both protect wildlife populations in the wild and facilitate sustainable use of wildlife resources to meet human needs. This call has become particularly urgent in light of the COVID-19 pandemic. In 2021, China's List of State Key Protected Wild Animals, a list of fauna under the strictest protection by national legislation, has been updated in the year 2021, 32 years after its first release, increasing its coverage (from the original 13%) an 11% of species across taxa. Combined with the updated List of State Protected Terrestrial Wild Animals which covers species with lower protection priority, these two national lists already cover 77% terrestrial vertebrate species of China. Such a blacklist approach, placing threatened species under a list of legal protection, is a common practice globally in species conservation. We discussed pros and cons of this dominant strategy and further explored the potential integration with a whitelist approach, listing all wildlife and only permitting regulated uses of certain species. We propose a mixed approach combining black and whitelists at different administration levels which could perhaps be first adopted in China. This is mainly due to the fact that in addition to illegal harvesting from the wild, traded wildlife in China are mostly from captive breeding and related laundering of wild-caught animals.
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The Kunming-Montreal Global Biodiversity Framework puts forward a new conservation target to enhance urban biodiversity. Cities have a great potential for sustaining biodiversity and nurturing a healthy relationship between people and our... more
The Kunming-Montreal Global Biodiversity Framework puts forward a new conservation target to enhance urban biodiversity. Cities have a great potential for sustaining biodiversity and nurturing a healthy relationship between people and our nearest nature. It is especially important in developing countries such as China, which has a rich biodiversity and a rapidly growing urban population. Using citizen science data, we show that 48% of the national bird diversity and 42% of its threatened species have been recorded in the top-20 most avian-diverse cities of China. Urban bird diversity hotspots clustered along the eastern coast, indicating the importance of establishing an inter-city conservation network along the East Asian-Australasian Flyway. This urban conservation network would be a starting point to promote social recognition of biodiversity’s relational value in a country with a vast population and an increasingly important role in meeting UN’s Sustainable Development Goals.
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Urbanization has dramatically altered Earth's landscapes and changed a multitude of environmental factors. This has resulted in intense land-use change, and adverse consequences such as the urban heat island effect (UHI), noise pollution,... more
Urbanization has dramatically altered Earth's landscapes and changed a multitude of environmental factors. This has resulted in intense land-use change, and adverse consequences such as the urban heat island effect (UHI), noise pollution, and artificial light at night (ALAN). However, there is a lack of research on the combined effects of these environmental factors on life-history traits and fitness, and on how these interactions shape food resources and drive patterns of species persistence. Here, we systematically reviewed the literature and created a comprehensive framework of the mechanistic pathways by which urbanization affects fitness and thus favors certain species. We found that urbanization-induced changes in urban vegetation, habitat quality, spring temperature, resource availability, acoustic environment, nighttime light, and species behaviors (e.g., laying, foraging, and communicating) influence breeding choices, optimal time windows that reduce phenological mismatch, and breeding success. Insectivorous and omnivorous species that are especially sensitive to temperature often experience advanced laying behaviors and smaller clutch sizes in urban areas. By contrast, some granivorous and omnivorous species experience little difference in clutch size and number of fledglings because urban areas make it easier to access anthropogenic food resources and to avoid predation. Furthermore, the interactive effect of land-use change and UHI on species could be synergistic in locations where habitat loss and fragmentation are greatest and when extreme-hot weather events take place in urban areas. However, in some instances, UHI may mitigate the impact of land-use changes at local scales and provide suitable breeding conditions by shifting the environment to be more favorable for species' thermal limits and by extending the time window in which food resources are available in urban areas. As a result, we determined five broad directions for further research to highlight that urbanization provides a great opportunity to study environmental filtering processes and population dynamics.
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Protected areas provide essential habitats for wildlife by conserving natural and semi-natural habitats and reducing human disturbance. However, whether breeding birds vulnerable to nest predation can benefit from strict land management... more
Protected areas provide essential habitats for wildlife by conserving natural and semi-natural habitats and reducing human disturbance. However, whether breeding birds vulnerable to nest predation can benefit from strict land management in the protected area is unclear. Here, we compare the nesting performance of two groups of a ground-nesting shorebird, the Kentish plover (Charadrius alexandrinus), in the protected area (Liaohekou Natural Reserve, hereinafter PA), and the control non-protected area (non-PA) around the Liaohekou Natural Reserve, in the north of the Yellow Sea, China, and identify which environmental factors, such as nesting habitat and nest materials, influence the daily nest survival rate (DSR). We found similar nesting habitats in both study areas, dominated by bare land or Suaeda salsa grassland. However, DSR was lower in PA (0.91 ± 0.01) than in non-PA (0.97 ± 0.01). Kentish plovers nesting in areas with vegetation cover experienced lower DSR than in bare lands in both areas, and nests built with materials of S. salsa sticks had the lowest DSR in the bare land. Data from infrared cameras confirmed relatively higher predator abundances and nest predation rates by nocturnal mammals, such as Eurasian badgers (Meles meles), in PA than in non-PA, and this pattern was especially evident for plover nests located in S. salsa grassland. Our results suggest that Liaohekou Natural Reserve protected area may not necessarily provide safe nesting sites for Kentish plovers due to the abundance of generalist mammal nest predators. However, the PA includes about 80% of the nests from both locations. This means the contribution of the total number of successful nests continues to be much higher within PA, with the benefit for the species that this brings in terms of conservation. The variation and mechanisms underlying differences in the nest predator communities of PA and non-PA deserve further study.
Research Interests:
In addition to landscape changes, urbanization also brings about changes in environmental factors that can affect wildlife. Despite the common referral in the published literature to multiple environmental factors such as light and noise... more
In addition to landscape changes, urbanization also brings about changes in environmental factors that can affect
wildlife. Despite the common referral in the published literature to multiple environmental factors such as light
and noise pollution, there is a gap in knowledge about their combined impact. We developed a multidimensional
environmental framework to assess the effect of urbanization and multiple environmental factors (light, noise,
and temperature) on life-history traits and breeding success of Barn Swallows (Hirundo rustica) across rural to
urban gradients in four locations spanning over 2500 km from North to South China. Over a single breeding
season, we measured these environmental factors nearby nests and quantified landscape urbanization over a 1
km2 radius. We then analysed the relationships between these multiple environmental factors through a principal
component analysis and conducted spatially explicit linear-mixed effects models to assess their effect on lifehistory
traits and breeding success. We were particularly interested in understanding whether and how Barn
Swallows were able to adapt to such environmental conditions associated with urbanization. The results show
that there is significant variation in the exposure to environmental conditions experienced by Barn Swallows
breeding across urbanization gradients in China. These changes and their effects are complex due to the
behavioural responses ameliorating potential negative effects by selecting nesting sites that minimize exposure to
environmental factors. However, significant relationships between landscape urbanization, exposure to environmental
factors, and life-history traits such as laying date and clutch size were pervasive. Still, the impact on
breeding success was, at least in our sample, negligible, suggesting that Barn Swallows are extremely adaptable to
a wide range of environmental features.
wildlife. Despite the common referral in the published literature to multiple environmental factors such as light
and noise pollution, there is a gap in knowledge about their combined impact. We developed a multidimensional
environmental framework to assess the effect of urbanization and multiple environmental factors (light, noise,
and temperature) on life-history traits and breeding success of Barn Swallows (Hirundo rustica) across rural to
urban gradients in four locations spanning over 2500 km from North to South China. Over a single breeding
season, we measured these environmental factors nearby nests and quantified landscape urbanization over a 1
km2 radius. We then analysed the relationships between these multiple environmental factors through a principal
component analysis and conducted spatially explicit linear-mixed effects models to assess their effect on lifehistory
traits and breeding success. We were particularly interested in understanding whether and how Barn
Swallows were able to adapt to such environmental conditions associated with urbanization. The results show
that there is significant variation in the exposure to environmental conditions experienced by Barn Swallows
breeding across urbanization gradients in China. These changes and their effects are complex due to the
behavioural responses ameliorating potential negative effects by selecting nesting sites that minimize exposure to
environmental factors. However, significant relationships between landscape urbanization, exposure to environmental
factors, and life-history traits such as laying date and clutch size were pervasive. Still, the impact on
breeding success was, at least in our sample, negligible, suggesting that Barn Swallows are extremely adaptable to
a wide range of environmental features.
Research Interests:
Resolving trade-offs between economic development and biodiversity conservation needs is one of the defining issues of our time. This is crucial in currently developing countries and in particularly sensitive systems harboring high... more
Resolving trade-offs between economic development and biodiversity conservation needs is one of the defining issues of our time. This is crucial in currently developing countries and in particularly sensitive systems harboring high biodiversity. Yet, such a task can be challenging as human activities may have complex effects on biodiversity. Here we assessed the effects of intense economic development on different components of biodiversity using Hainan Island (South China) as model. This highly biodiverse tropical island has experienced intense economic development and extensive forest to agriculture conversion and urbanization across the last two decades. We characterized three main habitat clusters, based on local land use, climate and economic changes across 145 grids (10×10 km), and estimated avian biodiversity responses between 1998 and 2013. We recorded ongoing taxonomic biotic homogenization at the regional scale (i.e., the whole island), evidenced by decreasing differences between traditional and directional alpha diversity. Communities became overall phylogenetically clustered and functionally overdispersed. Biodiversity's priority effects were pervasive, with less diverse communities showing positive and more diverse communities showing negative biodiversity changes. Finally, at the local scale, different economic and environmental indicators showed complex and divergent effects across habitat clusters and biodiversity components. These effects were only partially ameliorated within a newly established Ecological Function Conservation Area in the mountainous central part of the island. Thus, our results depict complex effects of economic development on different biodiversity dimensions in different areas of the island with different land uses and protection regimes, and between local and regional spatial scales. Profound ecosystem damage associated with economic development was partially averted, probably due to enhanced biodiversity conservation policies and law enforcement, yet at the cost of regional-scale biotic homogenization and local-scale biodiversity loss.
Research Interests:
Aposematic organisms defend themselves through various means to increase their unprofitability to predators which they advertise with conspicuous warning signals. Predators learn to avoid aposematic prey through associative learning that... more
Aposematic organisms defend themselves through various means to increase their unprofitability to predators which they advertise with conspicuous warning signals. Predators learn to avoid aposematic prey through associative learning that leads to lower predation. However, when these visual signals become unreliable (e.g., through automimicry or Batesian mimicry), predators may switch from using visual signals to taste sampling prey to choose among them. In this experiment, we tested this possibility in a field experiment where we released a total of 4800 mealworm prey in two clusters consisting of either: (i) undefended prey (injected with water) and (ii) model-mimics (injected with either quinine sulphate [models] or water [mimics]). Prey were deployed at 12 sites, with the mimic frequency of the model-mimics ranging between 0 and 1 (at 0.2 intervals). We found that taste rejection peaked at moderate mimic frequencies (0.4 and 0.6), supporting the idea that taste sampling and rejection of prey is related to signal reliability and predator uncertainty. This is the first time that taste-rejection has been shown to be related to the reliability of prey signals in a mimetic prey system.
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The COVID-19 pandemic has strongly disrupted academic activities, particularly in disciplines with a strong empirical component among other reasons by limiting our mobility. It is thus essential to assess emergency remote teaching plans... more
The COVID-19 pandemic has strongly disrupted academic activities, particularly in disciplines with a strong empirical component among other reasons by limiting our mobility. It is thus essential to assess emergency remote teaching plans by surveying learners’ opinions and perceptions during these unusual circumstances. To achieve this aim, we conducted a survey during the spring semester of 2021 in an environmental science program to ascertain learners’ perceptions on online and onsite learning activities in ecology-based modules. We were particularly interested not only in comparing the performance of these two types of activities but also in understanding the role played by learners’ perceptions about nature in shaping this pattern. Environmental science programs are rather heterogeneous from a conceptual point of view and, thus, learners may also be more diverse than in traditional ecology programs, which may affect their interest for ecology-based modules. We assessed connectedness to nature by computing the reduced version of the Nature Relatedness Scale. Here, we found that online activities systematically obtained significantly lower scores than onsite activities regardless of the wording employed, and that altruistic behaviors were prevalent among learners. Interestingly, scores for both onsite and online activities were strongly influenced by learners’ connectedness to nature, as learners with a stronger connection to nature gave higher scores to both types of activities. Our results suggest that an effort to improve the efficacy of remote learning activities should be the focus of research about teaching methodologies in predominantly empirical scientific disciplines.
Research Interests:
Migratory divides are contact zones between breeding populations with divergent migratory strategies during the nonbreeding season. These locations provide an opportunity to evaluate the role of seasonal migration in the maintenance of... more
Migratory divides are contact zones between breeding populations with divergent migratory strategies during the nonbreeding season. These locations provide an opportunity to evaluate the role of seasonal migration in the maintenance of reproductive isolation, particularly the relationship between population structure and features associated with distinct migratory strategies. We combine light-level geolocators, genomic sequencing, and stable isotopes to investigate the timing of migration and migratory routes of individuals breeding on either side of a migratory divide coinciding with genomic differentiation across a hybrid zone between barn swallow (Hirundo rustica) subspecies in China. Individuals west of the hybrid zone, with H. r. rustica ancestry, had comparatively enriched stable-carbon and hydrogen isotope values and overwintered in eastern Africa, whereas birds east of the hybrid zone, with H. r. gutturalis ancestry, had depleted isotope values and migrated to southern India. The two subspecies took divergent migratory routes around the high-altitude Karakoram Range and arrived on the breeding grounds over 3 weeks apart. These results indicate that assortative mating by timing of arrival and/or selection against hybrids with intermediate migratory traits may maintain reproductive isolation between the subspecies, and that inhospitable geographic features may have contributed to the diversification of Asian avifauna by influencing migratory patterns.
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Multidimensional approaches examining complex trait-niche relationships are crucial to understand community assembly. This is particularly important across habitat transformation gradients because specialists are progressively substituted... more
Multidimensional approaches examining complex trait-niche relationships are crucial to understand community assembly. This is particularly important across habitat transformation gradients because specialists are progressively substituted by generalists and, despite increasing functional homogenization, in both specialist and generalist communities niche partitioning is apparent. Here, in line with the continuum hypothesis, we expected that divergent trait-niche relationships would arise in passerine assemblages across the natural-to-urban transformation gradient. More specifically, we expected that traits linking form to function would be more important in less transformed habitats, while population density and traits linked to dispersal and dominance would predominate in more transformed habitats. Accordingly, we found that beak length and its interaction with tarsus length correlated significantly with isotopic niches in natural and rural habitats, where specialists predominate. Conversely, body size and aggressiveness only showed significant relationships with isotopic niches with increasing habitat transformation, where generalists prevail. Interestingly, we recorded a mix of these processes in rural habitats, which acted as a frontier between these two domains. Our study is thus important in showing that a complex combination of morphological and behavioral traits determine niche characteristics, and that these relationships are dynamic across habitat transformation gradients.
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Asia is a land of contrasts. This is the largest and most populated continent of the world, it is where urbanization is increasing at the highest rate (Seto et al., 2012). At the same time, it is extremely biodiverse (Myers et al., 2000),... more
Asia is a land of contrasts. This is the largest and most populated continent of the world, it is where urbanization is increasing at the highest rate (Seto et al., 2012). At the same time, it is extremely biodiverse (Myers et al., 2000), so that promoting harmonious human-wildlife coexistence is complex. This complexity is not recent. Ancient civilizations populating this area have left a lasting impact on its nature (Ellis et al., 2021), and recent impacts add to these historical effects. This issue is acknowledged by governments across Asia, who have recently developed numerous initiatives to protect their biodiversity (Ghosh-Harihar et al., 2019; Wu et al., 2019). Yet, despite increasing regional conservation efforts, not all species will make it. For instance, millions-year old species are still being led to extinction (Zhang et al., 2020). In a recent positive development, the United Nations' Convention for Biodiversity (COP-15) will set a 30% threshold of protected areas of terrestrial land (Zhu et al., 2021). But, to achieve such an ambitious biodiversity conservation goal, urgent action is needed.
This Research Topic aimed to assess the impacts that human-driven habitat transformation has on species, biodiversity, and ecosystems in Asia, and to envision ways in which these impacts can be minimized. Moreover, our intention was to bring together research works from around Asia (and the rest of the world) which address this issue. We gathered papers authored by researchers from 8 countries, i.e., India, China, Singapore, Australia, Pakistan, Brunei, Sri Lanka, and United States. We are convinced that collaboration among Asian nations is an essential condition for any meaningful biodiversity conservation targets to be achieved (Chen et al., 2019; Bawa et al., 2020). We are also convinced that biodiversity conservation should develop interdisciplinary approaches outside the boundaries of traditional academic disciplines, and that it should be science that addresses people's and nature's needs (Kremen and Merenlender, 2018). This collection of 12 papers is our humble contribution to achieve these conservation targets in Asia.
This Research Topic aimed to assess the impacts that human-driven habitat transformation has on species, biodiversity, and ecosystems in Asia, and to envision ways in which these impacts can be minimized. Moreover, our intention was to bring together research works from around Asia (and the rest of the world) which address this issue. We gathered papers authored by researchers from 8 countries, i.e., India, China, Singapore, Australia, Pakistan, Brunei, Sri Lanka, and United States. We are convinced that collaboration among Asian nations is an essential condition for any meaningful biodiversity conservation targets to be achieved (Chen et al., 2019; Bawa et al., 2020). We are also convinced that biodiversity conservation should develop interdisciplinary approaches outside the boundaries of traditional academic disciplines, and that it should be science that addresses people's and nature's needs (Kremen and Merenlender, 2018). This collection of 12 papers is our humble contribution to achieve these conservation targets in Asia.
Research Interests:
Diet specialisation during brood rearing has important consequences on parental reproductive success and on the recruitment rate of offspring. However, very little is known about the long-term consistency of parents when feeding their... more
Diet specialisation during brood rearing has important consequences on parental reproductive success and on the recruitment rate of offspring. However, very little is known about the long-term consistency of parents when feeding their offspring. Here, we used Mediterranean Great Tits Parus major to test the hypothesis that parents show a consistent level of individual specialisation across years. To do this, we recorded prey delivered to 10-14 day-old chicks over six years. We standardised the data to control for environmental factors and used a Principal Component Analysis (PCA) to characterise the foraging provisioning behaviour of individuals. We assessed long-term dietary consistency using data from individuals recorded in two different years by performing a repeatability analysis (absolute consistency) and also running a Generalised Linear Mixed Model, where we measured the consistency of position of individuals in a group, relative to others (relative consistency). The PCA analysis showed that diet selection when provisioning chicks varies across two gradients: prey size vs. frequency of prey delivery, and caterpillars vs. spiders. Controlling for these factors, we found that both individual repeatability and the correlation of diet choices between years were moderately significant. Although Great Tits show high individual dietary specialisation within a year, diet fluctuates to some extent across years. This could provide a degree of flexibility to parents dealing with highly fluctuating environmental conditions as well as a buffer against climate change, and could be a consequence of increasing lifetime experience.
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Species in transformed habitats, frequently labelled as environmental generalists, tend to show broader niches than species in natural habitats. However, how population niche expansion translates into changes in the niches of individual... more
Species in transformed habitats, frequently labelled as environmental generalists, tend to show broader niches than species in natural habitats. However, how population niche expansion translates into changes in the niches of individual organisms remains unclear, particularly in the context of habitat transformation. Niche expansion could be a product of individuals having broader niches, greater distances among individuals’ niches, or a combination of both processes. This would challenge the traditional conceptions on niche dynamics, which emphasize the role played by individual specialization (IS). Here, using stable isotopes, we computed total niche width (TNW), its within- and between-individual components (WIC & BIC), and IS (the ratio WIC/TNW), in 13 populations of 6 bird species and 8 populations of 3 frog species in natural and transformed habitats. We confirmed that species had broader niche width in transformed than in natural habitats, yet population niche expansion across habitats was mainly a product of increased distance between individuals. Within each habitat type, increases in TNW were linked to increases in WIC for all habitat types, while relationships between TNW and BIC were found in transformed but not in natural habitats. Hence, both increased individual niche width and increased distance among individuals were apparent within habitats, particularly in transformed ones, where increases in WIC dominated. Neither across or within habitats was niche expansion associated with increasing IS. Therefore, our results overturn traditional conceptions associated with the niche variation hypothesis and illustrate that niche expansion is not invariably associated with increased IS, because the distance between individual’s niches (BIC) can increase, as well as the breadth of those niches (WIC).
Research Interests:
Urbanization implies a dramatic impact on ecosystems, which may lead to drastic phenotypic differences between urban and nonurban individuals. For instance, urbanization is associated with increased metabolic costs, which may constrain... more
Urbanization implies a dramatic impact on ecosystems, which may lead to drastic phenotypic differences between urban and nonurban individuals. For instance, urbanization is associated with increased metabolic costs, which may constrain body size, but urbanization also leads to habitat fragmentation, which may favor increases in body mass when for instance it correlates with dispersal capacity. However, this apparent contradiction has rarely been studied. This is particularly evident in China where the urbanization process is currently occurring at an unprecedented scale. Moreover, no study has addressed this issue across large geographical areas encompassing locations in different climates. In this regard, Barn Swallows (Hirundo rustica) are a suitable model to study the impact of urbanization on wild animals because they are a widely distributed species tightly associated with humans. Here, we collected body mass and wing length data for 359 breeding individuals of Barn Swallow (H. r. gutturalis) from 128 sites showing different levels of urbanization around the whole China. Using a set of linear mixed-effects models, we assessed how urbanization and geography influenced body size measured using body mass, wing length, and their regression residuals. Interestingly, we found that the impact of urbanization was sex-dependent, negatively affecting males' body mass, its regression residuals, and females' wing length. We also found that northern and western individuals were larger, regarding both body mass and wing length, than southern and eastern individuals. Females were heavier than males, yet males had slightly longer wings than females. Overall, our results showed that body mass of males was particularly sensitive trait to urbanization, latitude, and longitude, while it only showed a weak response to latitude in females. Conversely, while wing length showed a similar geographical pattern, it was only affected by urbanization in the case of females. Further research is needed to determine whether these phenotypic differences are associated with negative effects of urbanization or potential selective advantages.
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Migratory shorebirds select stopover sites to fuel their migration across heterogeneous coastal landscapes with abundant prey resources. Quantifying the degree of dietary specialization between closely-related species and how they... more
Migratory shorebirds select stopover sites to fuel their migration across heterogeneous coastal landscapes with abundant prey resources. Quantifying the degree of dietary specialization between closely-related species and how they partition resources across different coastal habitat types during both spring and autumn migration could identify some interesting possibilities for conservation management given the extent of anthropogenic habitat degradation at critical stopover sites. Here we used a comparative approach to examine diet specialization and feeding rates of two migratory Numenius curlew species, Far Eastern Curlew Numenius madagascariensis and Eurasian Curlew N. arquata populations, at an important stopover site in the Yellow Sea, China, and to assess the influence of habitat type, presence of human disturbance (activities related to aquaculture and oil production), and migratory season on their feeding behavior. Far Eastern Curlews were more dependent on tidal crabs and exhibited less dietary flexibility than its closely-related congener. Feeding rates on crabs by Far Eastern Curlews were not significantly different between mudflat and Suaeda salsa saltmarsh habitat but were negatively influenced by human disturbance and were higher during spring migration. In contrast, these effects were not apparent for Eurasian Curlew which fed predominantly on ragworms in saltmarsh habitat. The differences in prey type and feeding rates between adjacent habitats and migration seasons could explain how these two congeners fit syntopically along coastal wetland resource gradients. The extensive utilization of S. salsa habitat by both species suggests that saltmarshes represent an important feeding habitat for these species and that further conservation efforts aimed at reducing human disturbance would benefit both species and may lead to improved feeding rates for Far Eastern Curlews.
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Aposematic organisms are often unprofitable to predators (e.g. because of defensive chemicals) which they advertise with a conspicuous signal (e.g. bright and conspicuous colour signals). Aposematism is thought to reduce predation of prey... more
Aposematic organisms are often unprofitable to predators (e.g. because of defensive chemicals) which they advertise with a conspicuous signal (e.g. bright and conspicuous colour signals). Aposematism is thought to reduce predation of prey because the colour signal increases the ability of predators to learn, recognize and remember the prey’s defensive properties. The efficacy of aposematism has been extensively documented in laboratory studies, although its benefits seem to be harder to demonstrate in the field. In this study, we compared the levels of partial and overall predation among four prey types (undefended and cryptic, undefended and warning coloured, defended and cryptic, and aposematic prey). Overall, predation of warning coloured and defended (aposematic) prey was lower than the predation for cryptic and undefended prey; however, it was the same as predation of cryptic and defended prey. Moreover, aposematic prey had higher levels of partial predation (where prey was not wholly consumed by the predator) and lower attack intensities. This suggests that prey were being taste sampled, but also might be better able to survive attacks. Therefore, the benefits of aposematism may lie not only in reducing outright predation, but also in altering a predator’s post-attack behaviour, thus leading to greater escape opportunities and post-attack survival of prey. These results reinforce the importance of examining predation in more detail rather than simply examining attack rates.
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Western voices claim that China needs “to discredit engrained cultural beliefs” to make the country’s ban on wildlife trade workable (see J. Ribeiro et al. Nature 578, 217; 2020). This stereotyped perception of Chinese society disregards... more
Western voices claim that China needs “to discredit engrained cultural beliefs” to make the country’s ban on wildlife trade workable (see J. Ribeiro et al. Nature 578, 217; 2020). This stereotyped perception of Chinese society disregards the country’s huge support for the ban, thanks to efforts by conservationists and the government, as well as evidence that traditional wild-meat consumption is in decline — particularly in the young and in large urban areas (see, for example, go.nature.com/3d8za5i and go.nature.com/33qglzs; in Chinese).
Ribeiro and colleagues’ perception of archaic beliefs that are grounded in agricultural–pastoral societies is misplaced. Efficient policies aiming to decrease wildlife trade should involve law enforcement and reduction of both supply and demand. Comments on policies and cultural beliefs, particularly when these are made from high-income to low- or middle-income countries, should be more respectful of cultural diversity. A ban on orientalism is long overdue.
Ribeiro and colleagues’ perception of archaic beliefs that are grounded in agricultural–pastoral societies is misplaced. Efficient policies aiming to decrease wildlife trade should involve law enforcement and reduction of both supply and demand. Comments on policies and cultural beliefs, particularly when these are made from high-income to low- or middle-income countries, should be more respectful of cultural diversity. A ban on orientalism is long overdue.
Research Interests:
Background Speciation with gene flow is an alternative to the nascence of new taxa in strict allopatric separation. Indeed, many taxa have parapatric distributions at present. It is often unclear if these are secondary contacts, e.g.... more
Background
Speciation with gene flow is an alternative to the nascence of new taxa in strict allopatric separation. Indeed, many taxa have parapatric distributions at present. It is often unclear if these are secondary contacts, e.g. caused by past glaciation cycles or the manifestation of speciation with gene flow, which hampers our understanding of how different forces drive diversification. Here we studied genetic, phenotypic and ecological aspects of divergence in a pair of incipient shorebird species, the Kentish (Charadrius alexandrinus) and the White-faced Plovers (C. dealbatus), shorebirds with parapatric breeding ranges along the Chinese coast. We assessed divergence based on molecular markers with different modes of inheritance and quantified phenotypic and ecological divergence in aspects of morphometric, dietary and climatic niches.
Results
Our integrative analyses revealed small to moderate levels of genetic and phenotypic distinctiveness with symmetric gene flow across the contact area at the Chinese coast. The two species diverged approximately half a million years ago in dynamic isolation with secondary contact occurring due to cycling sea level changes between the Eastern and Southern China Sea in the mid-late Pleistocene. We found evidence of character displacement and ecological niche differentiation between the two species, invoking the role of selection in facilitating divergence despite gene flow.
Conclusion
These findings imply that ecology can indeed counter gene flow through divergent selection and thus contributes to incipient speciation in these plovers. Furthermore, our study highlights the importance of using integrative datasets to reveal the evolutionary history and assist the inference of mechanisms of speciation.
Speciation with gene flow is an alternative to the nascence of new taxa in strict allopatric separation. Indeed, many taxa have parapatric distributions at present. It is often unclear if these are secondary contacts, e.g. caused by past glaciation cycles or the manifestation of speciation with gene flow, which hampers our understanding of how different forces drive diversification. Here we studied genetic, phenotypic and ecological aspects of divergence in a pair of incipient shorebird species, the Kentish (Charadrius alexandrinus) and the White-faced Plovers (C. dealbatus), shorebirds with parapatric breeding ranges along the Chinese coast. We assessed divergence based on molecular markers with different modes of inheritance and quantified phenotypic and ecological divergence in aspects of morphometric, dietary and climatic niches.
Results
Our integrative analyses revealed small to moderate levels of genetic and phenotypic distinctiveness with symmetric gene flow across the contact area at the Chinese coast. The two species diverged approximately half a million years ago in dynamic isolation with secondary contact occurring due to cycling sea level changes between the Eastern and Southern China Sea in the mid-late Pleistocene. We found evidence of character displacement and ecological niche differentiation between the two species, invoking the role of selection in facilitating divergence despite gene flow.
Conclusion
These findings imply that ecology can indeed counter gene flow through divergent selection and thus contributes to incipient speciation in these plovers. Furthermore, our study highlights the importance of using integrative datasets to reveal the evolutionary history and assist the inference of mechanisms of speciation.
Research Interests:
https://onlinelibrary.wiley.com/doi/abs/10.1111/ecog.04203 Human‐mediated habitat transformation is increasingly evident around the world. Yet, how this transformation influences species’ niche width and overlap remains unclear. On the... more
https://onlinelibrary.wiley.com/doi/abs/10.1111/ecog.04203
Human‐mediated habitat transformation is increasingly evident around the world. Yet, how this transformation influences species’ niche width and overlap remains unclear. On the one hand, human‐mediated habitat transformation promotes increased species similarity through trait‐based filtering, and an increased prevalence of generalist species with broad niches, resulting in functional homogenization. On the other hand, species that colonize transformed habitats could use empty niches, resulting in decreased species similarity and an expansion of assemblage‐level niche space. Here we explore these two alternatives in eight highly diverse passerine assembles in natural, rural and urban habitats in South and Southwest China, a rapidly developing region of the world. Based on stable isotopes, we found that species’ niche width increased from natural to human‐made habitats, but there were no differences in niche overlap among habitats. Therefore, we found evidence for niche expansion, with generalists appearing to use empty niches created by human habitat modification, and with assemblages being comprised of complementary species. Further research is needed to determine whether increased between‐ or within‐individual niche variation is the main driver of niche expansion in transformed habitats.
Human‐mediated habitat transformation is increasingly evident around the world. Yet, how this transformation influences species’ niche width and overlap remains unclear. On the one hand, human‐mediated habitat transformation promotes increased species similarity through trait‐based filtering, and an increased prevalence of generalist species with broad niches, resulting in functional homogenization. On the other hand, species that colonize transformed habitats could use empty niches, resulting in decreased species similarity and an expansion of assemblage‐level niche space. Here we explore these two alternatives in eight highly diverse passerine assembles in natural, rural and urban habitats in South and Southwest China, a rapidly developing region of the world. Based on stable isotopes, we found that species’ niche width increased from natural to human‐made habitats, but there were no differences in niche overlap among habitats. Therefore, we found evidence for niche expansion, with generalists appearing to use empty niches created by human habitat modification, and with assemblages being comprised of complementary species. Further research is needed to determine whether increased between‐ or within‐individual niche variation is the main driver of niche expansion in transformed habitats.
Research Interests:
We analysed niche overlap between the red–billed leiothrix Leiothrix lutea, a spreading exotic invasive bird, and the European robin Erithacus rubecula and the blackcap Sylvia atricapilla, similar native species, which are commonly... more
We analysed niche overlap between the red–billed leiothrix Leiothrix lutea, a spreading exotic invasive bird, and the European robin Erithacus rubecula and the blackcap Sylvia atricapilla, similar native species, which are commonly considered as potential competitors in Mediterranean forests. We analyzed stable isotope ratios (δ13C and δ15N) from feathers of birds sampled in several locations within the Collserola mountain range (Barcelona, NE Spain) where leiothrix have strongly increased their numbers in the last decade and quantified niche overlap with nicheROVER. Blackcap individuals showed the lowest probability to be found in the isotopic niche of the other two species (around 60 %), while leiothrix and robins showed a high probability to share the same isotopic niche (82 %). Our results stress that competition for resources is potentially high and the species shared marked niche asymmetries, which may have implications for community dynamics in the long term.
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The pace-of-life hypothesis predicts no impact of urbanization on stress responses. Accordingly, several studies have been inconsistent in showing differences in breath rate (BR), a proxy of acute stress responses to handling in... more
The pace-of-life hypothesis predicts no impact of urbanization on stress responses. Accordingly, several studies have been inconsistent in showing differences in breath rate (BR), a proxy of acute stress responses to handling in passerines, between rural and urban areas. However, this evidence is limited to a single bird species and a limited geographical region (SW Europe). No study addressed whether this pattern is also apparent in other species or regions, such as in tropical environments, or whether it is dependent on the level of diet specialization, given that diet restriction and change influence stress responses. Here, we tested if there were differences in BR between habitats and diet groups using eight highly diverse passerine assemblages experiencing different levels of anthropogenic disturbance (i.e. natural, rural and urban locations) in SW China. We predicted that insectivores and herbivores (frugivores, nectarivores and seed-eating species) would show higher BR than omnivores. We also predicted no differences in BR among habitat types. BR was a moderately repeatable trait, which showed a negative relationship with body mass and a positive relationship with the time of the day. We also recorded a relatively strong phylogenetic bias in the expression of this trait. Confirming our predictions, our results showed no differences in BR among natural, rural and urban locations. Similarly, within species, there were no differences in BR between rural and urban locations. However, we also found that herbivores showed higher BR than omnivores. Overall, our results provide support to the pace-of-life hypothesis, but suggest acute stress responses can be diet-mediated, which may help to explain the marked decline of specialized trophic guilds around the world in response to anthropogenic disturbance.
Research Interests:
Bird plumage is often very colourful and can communicate the quality of the bearer to conspecifics. These plumage-based signals of quality are composed of multiple pigments (e.g., melanin and carotenoids). Therefore, sex and age classes,... more
Bird plumage is often very colourful and can communicate the quality of the bearer to conspecifics. These plumage-based signals of quality are composed of multiple pigments (e.g., melanin and carotenoids). Therefore, sex and age classes, which often show marked differences in plumage colouration, may have different dietary needs for the different plumage components and this might promote preferences for different dietary niches at different moulting stages. However, no study has addressed the role that changes in niche use play in the expression of multiple component plumage signals in birds. We used stable isotope analysis to test the hypothesis that niche use is related to age and sex and to differently coloured plumage patches, yellow carotenoid-based and black melanin-based, in great tits Parus major. We recorded high niche overlap between plumage patches, although δ15N was higher in black than yellow plumage. Niche overlap was relatively low for age classes and relatively high for sex classes, and age classes showed a contrasting pattern of niche overlap between carotenoid- and melanin-based plumages. Moreover, δ13C, but not δ15N, had a significant negative relationship with carotenoid-based plumage, which was only apparent in juveniles. Taken together, our results demonstrate that niche use had a moderate influence on plumage colouration characteristics of great tit individuals, mostly associated with δ13C rather than with δ15N and with age rather than with sex. Therefore, our study is significant because it confirms the relevance of niche use during ornament production in free-living birds.
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What structures the organization of mixed-species bird flocks, so that some ‘nuclear’ species lead the flocks, and others follow? Previous research has shown that species actively listen to each other, and that leaders are gregarious;... more
What structures the organization of mixed-species bird flocks, so that some ‘nuclear’ species lead the flocks, and others follow? Previous research has shown that species actively listen to each other, and that leaders are gregarious; such gregarious species tend to make contact calls and hence may be vocally conspicuous. Here we investigated whether vocal characteristics are associated with leadership, using a global dataset of mixed-species flock studies and recordings from sound archives. We first asked whether leaders are different from following or occasional species in flocks in the proportion of the recordings that contain calls (n = 58 flock studies, 145 species), and especially alarm calls (n = 111 species). We found that leaders tended to have a higher proportion of their vocalizations that were classified as calls than occasional species, and both leaders and following species had a significantly higher proportion of their calls rated as alarms compared to occasional species. Next, we investigated the acoustic characteristics of flock participants’ calls, hypothesizing that leaders would make more calls, and have less silence on the recordings. We also hypothesized that leaders’ calls would be simple acoustically, as contact calls tend to be, and thus similar to each other, as well as being detectable, in being low frequency and with high frequence bandwidth. The analysis (n = 45 species, 169 recordings) found that only one of these predictions was supported: leading species were less often silent than following or occasional species. Unexpectedly, leaders’ calls were less similar to each other than occasional species. The greater amount of information available and the greater variety of that information support the hypothesis that leadership in flocks is related to vocal communication. We highlight the use of sound archives to ask questions about behavioral and community ecology, while acknowledging some limitations of such studies.
Research Interests:
The incubation behaviour of the Fire-tailed Sunbird Aethopyga ignicauda was measured using data loggers in the Hengduan Mountains, China, to test predictions of parental trade-off theory. Overall, female sunbirds prioritized incubation... more
The incubation behaviour of the Fire-tailed Sunbird Aethopyga ignicauda was measured using data loggers in the Hengduan Mountains, China, to test predictions of parental trade-off theory. Overall, female sunbirds prioritized incubation rather than self-feeding when temperatures were lowest, suggesting that brood demands may dominate parental behaviour in climatically extreme environments.
Research Interests:
Online version available at http://rdcu.be/sOdS Two main theories attempt to explain species coexistence: the neutral theory considers all the species as equivalents so biodiversity is mainly regarded as a function of total available... more
Online version available at http://rdcu.be/sOdS
Two main theories attempt to explain species coexistence: the neutral theory considers all the species as equivalents so biodiversity is mainly regarded as a function of total available resources (i.e. niche expansion), while the niche theory stresses the relevance of differences in niche use between species (i.e. niche packing). The relative importance of these forces is under discussion and has been largely tested in natural ecosystems. However, few studies have addressed this issue in tropical-urban environments. In this work we studied niche overlap asymmetries among the most common urban resident birds, and the effect of habitat type on this pattern, in a subtropical location of South China (Nanning, Guangxi). We found differences in abundances and niche use among species and urban habitats (parks, streets and orchards). We also recorded strong asymmetries in niche use between species, which we divided into three categories: species with positive asymmetries, which showed highly specific niches and were able to exploit other species’ niches; species with neutral asymmetries, which showed high levels of niche overlap with the rest of species; and species with negative asymmetries, which showed low specificity in their niches and were unable to exploit other species’ niches. These differences in niche use correlated with differences in fat scores. Species from the first group showed higher fat scores than other two groups. Ultimately, niche asymmetries correlated with species’ body condition and mediated their differences in abundance, which supports the view that in this urban context niche theory is more appropriate than neutral theory.
Two main theories attempt to explain species coexistence: the neutral theory considers all the species as equivalents so biodiversity is mainly regarded as a function of total available resources (i.e. niche expansion), while the niche theory stresses the relevance of differences in niche use between species (i.e. niche packing). The relative importance of these forces is under discussion and has been largely tested in natural ecosystems. However, few studies have addressed this issue in tropical-urban environments. In this work we studied niche overlap asymmetries among the most common urban resident birds, and the effect of habitat type on this pattern, in a subtropical location of South China (Nanning, Guangxi). We found differences in abundances and niche use among species and urban habitats (parks, streets and orchards). We also recorded strong asymmetries in niche use between species, which we divided into three categories: species with positive asymmetries, which showed highly specific niches and were able to exploit other species’ niches; species with neutral asymmetries, which showed high levels of niche overlap with the rest of species; and species with negative asymmetries, which showed low specificity in their niches and were unable to exploit other species’ niches. These differences in niche use correlated with differences in fat scores. Species from the first group showed higher fat scores than other two groups. Ultimately, niche asymmetries correlated with species’ body condition and mediated their differences in abundance, which supports the view that in this urban context niche theory is more appropriate than neutral theory.
Research Interests:
In the last decade, an increasing body of research has addressed the extent to which different individuals within a species or population specialize in their exploitation of different food resources, which is referred to as individual... more
In the last decade, an increasing body of research has addressed the extent to which different individuals within a species or population specialize in their exploitation of different food resources, which is referred to as individual diet specialization (IDS). Traditionally, researchers use the terms ‘specialist’ and ‘generalist’, despite the inability of these labels to capture all of the complexity of IDS. In this paper, we compare the dietary specialism of great tit Parus major and blue tit Cyanistes caeruleus at different temporal and spatial scales. We use these two species to illustrate the differences within and between species in individual levels of IDS. Both of these species show greater IDS in Mediterranean habitats, where resources are less plentiful and more variable than in Northern Europe. Additionally, we also emphasize that IDS within populations may change temporally. At the same time, there are differences between species, with great tits showing a higher capacity than blue tits to specialize at both the individual and the population level. Great tits can be considered generalists at the species level and specialists at the individual level, while blue tits can be considered generalists at both the species and the individual level. Our study demonstrates that there is a need for researchers to determine the relative importance of intrinsic factors (e.g. differences between species or individuals in their behavioral flexibility or cognitive capacity) and extrinsic factors (e.g. resource base) in shaping patterns of dietary specialization. We conclude that, within and among species, different individuals respond differently to similar environmental pressures, utilize different niches and develop different functions in the ecosystem depending on their type of IDS. Therefore, we propose that label ‘generalists’ should distinguish between facultative generalists, which can develop new specializations, and obligate generalists, which have a limited capacity to develop novel specializations.
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The ecology and life history of bird species inhabiting limestone forests, which are under major conservation threats, is currently poorly known. To cover this gap of knowledge, in this study we report for the first time on several... more
The ecology and life history of bird species inhabiting limestone forests, which are under major conservation threats, is currently poorly known. To cover this gap of knowledge, in this study we report for the first time on several aspects of the breeding ecology of the Blue-rumped Pitta (Pitta soror) and the Fairy Pitta (P. nympha) inhabiting two typical limestone forests of south China. The mean density of Fairy Pittas in our study locations was 3.13 ± 2.82 and 1.05 ± 2.09 individuals/km2. The Blue-rumped Pitta was common in Nonggang and showed a mean density of 4.67 ± 2.44 individuals/km2, yet was absent in the other. We found nine nests between February 2009 and June 2015, including five of the Blue-rumped Pitta and four of the Fairy Pitta. Blue-rumped Pittas laid 4.8 ± 0.4 eggs with a mean fresh mass of 8.10 ± 0.40 g. Fairy Pittas had a clutch size of 5.2 ± 0.45 eggs with a mean fresh mass of 6.03 ± 0.22 g. Blue-rumped and Fairy Pitta parents fed their nestlings 4.0 ± 1.2 times and 3.9 ± 1.5 times per hour, respectively. Earthworms were the most common food item delivered to nestlings by Blue-rumped (93.6%) and Fairy Pitta (91.2%) parents. Blue-rumped Pittas bred successfully in 40% of nests (two of five), whilst in the case of Fairy Pittas nest success reached 75% (three of four). The two Pittas had larger clutch sizes than in southern populations of the same species and also than most other bird species inhabiting limestone forests. This would imply that Pittas show differences in life history traits within limestone ecosystems.
Research Interests:
Carotenoid-based ornaments have been proposed to signal the ability to find food. The good-parent hypothesis suggests that females may rely on these carotenoid-based traits to assess male parental quality. A key question is whether the... more
Carotenoid-based ornaments have been proposed to signal the ability to find food. The good-parent hypothesis suggests that females may rely on these carotenoid-based traits to assess male parental quality. A key question is whether the quality of these ornaments correlates with their performance at the moment of breeding. In this study, we assessed the parental investment of Mediterranean Great Tits Parus major in the early morning as a function of several environmental factors and of parental ornamentation. We measured this by the time that parents started feeding their offspring at the start of the day. In the morning, parents need to rapidly respond to the food demands of their offspring, after a long night without food. An earlier start of provisioning could indicate higher parental investment (and/or greater foraging ability). Our data indicate that fathers that show higher hue in their carotenoid-based plumage – more greenish individuals – started feeding their offspring earlier, thereby expanding the time window in which they work, while females did not show a significant relationship between the onset of provisioning and ornamentation. Parents, particularly mothers, that started earlier, worked more intensely across the whole observation period. Furthermore, parents started earlier when they had larger broods. Finally, more ornamented parents worked at lower rates, while more ornamented mothers raised offspring that had better body condition, which is in line with the good parent hypothesis. Although our results indicate that more ornamented males start feeding their offspring earlier, overall we found mixed support for the hypothesis that carotenoid-based ornaments signal the parental quality of a mate.
Research Interests: Ornithology and Ecology
Some animal species are found in many environments and overwide distributions and may have adaptations to live in such different areas.The barn swallow Hirundo rustica is an example of a species that is able to thrive over a large... more
Some animal species are found in many environments and overwide distributions and may have adaptations to live in such different areas.The barn swallow Hirundo rustica is an example of a species that is able to thrive over a large geographic range and in many different environments.However, little is known of the breeding biology of this species in southern China. Here, we studied 18 breeding pairs of barn swallow H. r. gutturalis in Nanning, Guangxi, between April and July 2015. We studied its breeding fitness and parental investment. We found that tropical barn swallows bred from earlyApril to early July and had from two to five fledglings per brood. We also recorded a strong seasonal decrease of breeding success and nestling condition that has also been found in temperate regions. Nevertheless, nestlings showed relatively long wings and low body masses, which may have enabled three sets of parents to raise three broods per breeding season, more than in other Chinese populations. Generally, barn swallows breeding in the tropics showed a similar ecology to their conspecifics from temperate regions, probably due to the species’ niche specificity in urban
settings. Morphological differences detected in this study require further research based on larger sample sizes and on more detailed data from different climatic regions of Asia.
settings. Morphological differences detected in this study require further research based on larger sample sizes and on more detailed data from different climatic regions of Asia.
Research Interests: Ornithology and Ecology
The diet of wild animals has been studied using many different strategies, approaches and methods in recent decades. In this regard, stable isotopes analysis (SIA) is becoming a widespread tool, but no study has yet, to our knowledge,... more
The diet of wild animals has been studied using many different strategies, approaches and methods in recent decades. In this regard, stable isotopes analysis (SIA) is becoming a widespread tool, but no study has yet, to our knowledge, compared diet estimations from SIA with direct observations of the diet of passerine nestlings. Accordingly, our aim was to test the predictive power of SIA for this purpose and identify potential confounding factors such as habitat effects. To do this, we compared isotopic signatures of δ13C and δ15N in the feathers of great tit (Parus major) nestlings, and the corresponding estimates of their diet based on stable isotope mixing models, with prey proportions delivered by their parents obtained through video-recordings. Between-nest differences in isotopic signatures of δ15N were larger than within-nest differences. We found that δ15N signatures of nestling feathers correlated positively with the proportion of spiders and negatively with the proportion of caterpillars in the nestlings’ diet, the most important prey types. On the other hand, between-nest and within-nest differences in δ13C ratios were of similar magnitude and δ13C ratios correlated mainly with the proportion of trees surrounding nest-boxes that were Quercus spp. Estimates of diet composition based on mixing models correlated with the observed nestling diet, yet effect sizes were quite low. Although mixing models are commonly used to ascertain diets, our data show that they can provide valuable information on the relative intake of prey types from different trophic levels; but when complex dietary patterns are recorded (e.g. due to the confounding effects of habitat and/or temporal variation) it can be difficult to draw firm conclusions about diet composition.
Research Interests:
The analysis of diet specialization provides key information on how different individuals deal with similar food and habitat constraints within populations. Characterizing parental diet specialization at the moment of breeding, and the... more
The analysis of diet specialization provides key information on how different individuals deal with similar food and habitat constraints within populations. Characterizing parental diet specialization at the moment of breeding, and the consistency of these preferences under different levels of effort, may help us to understand why parents exploit alternative resources. We investigated these questions in a species commonly considered a generalist: a breeding population of Mediterranean great tits Parus major. Our aim was to determine whether they are specialists or generalists at the pair level, and the consistency of this behaviour under different levels of effort. Using proportional similarity and mean pairwise overlap indices, we found that parents showed great variability in prey selection between territories. That is, they displayed a small niche overlap. Interestingly, the most specialized breeding pairs showed a tendency to have larger broods. Additionally, we experimentally manipulated brood size and found that parents showed high short-term consistency in their foraging behaviour. They precisely adjusted the number of provisioning trips to the number of nestlings, while they were unable to modify prey proportions or prey size after brood size was changed. We can therefore characterize their foraging strategies as highly consistent. Our results suggest that although the great tit may be considered a generalist at the species or population level, there was a tendency for trophic specialization among breeding pairs. This high inter- and intrapopulation plasticity could account for their great success and wide distribution.
Research Interests:
Behavioural research traditionally focusses on the mean responses of a group of individuals rather than variation in behaviour around the mean or among individuals. However, examining the variation in behaviour among and within... more
Behavioural research traditionally focusses on the mean responses of a group of individuals rather than variation in behaviour around the mean or among individuals. However, examining the variation in behaviour among and within individuals may also yield important insights into the evolution and maintenance of behaviour. Repeatability is the most commonly used measure of variability among individuals in behavioural research. However, there are other forms of variation within populations that have received less attention. One such measure is intraindividual variation in behaviour (IIV), which is a short-term fluctuation of within-individual behaviour. Such variation in behaviour might be important during interactions because it could decrease the ability of conspecific and heterospecific individuals to predict the behaviour of the subject, thus increasing the cost of the interaction. In this experiment, we made repeated measures of the latency of North Island robins to attack a prey in a novel situation (a form of boldness) and examined (i) repeatability of boldness (the propensity to take a risk), (ii) IIV of boldness, and (iii) whether there was a significant relationship between these two traits (a behavioural syndrome). We found that boldness was highly repeatable, that there were high levels of IIV in boldness, and that there was a negative relationship between boldness and IIV in boldness. This suggests that despite high levels of repeatability for this behaviour, there were also still significant differences in IIV among different individuals within the population. Moreover, bolder individuals had significantly less IIV in their boldness, which suggests that they were forming routines (which reduces behavioural variability) compared to shyer individuals. Therefore, IIV is a form individual behavioural variation that needs greater consideration in the study of behaviour as it could alter the costs of interactions between individuals.
Research Interests:
A key topic in foraging ecology is whether a particular prey type is consumed because it is more abundant or easier to catch, or because there is a specific preference for it. The great tit Parus major is an ideal species for studying... more
A key topic in foraging ecology is whether a particular prey type is consumed because it is more abundant or easier to catch, or because there is a specific preference for it. The great tit Parus major is an ideal species for studying this topic. Although it is traditionally regarded as a caterpillar specialist, in certain periods, e.g. during the breeding season, or areas, such as the Mediterranean forests, the great tit seems to show a preference for spiders. We conducted food choice experiments with captive birds to ascertain which of these two main prey types (caterpillars vs. spiders) was preferred outside the breeding season when there was an opportunity to prey on both food types. In conclusion, we found that, regardless of any variation in the supply-demand ratio and the amount of food available, Mediterranean great tits showed a preference for spiders.
Research Interests:
Resource partitioning is a central issue in ecology because it can establish to which point similar species can coexist in the same habitat. Great tits and blue tits have been classical model species in studies of trophic competence.... more
Resource partitioning is a central issue in ecology because it can establish to which point similar species can coexist in the same habitat. Great tits and blue tits have been classical model species in studies of trophic competence. However, most studies on the topic have been conducted at localities where caterpillars are by far the most relevant prey brought to the nestlings. In Mediterranean mixed forests, nevertheless, the abundance of caterpillars is relatively low and it is spiders that play a key role in the diet of great tits, at least for nestlings. The aim of this paper was to study nest food provisioning to establish the degree of diet overlap of these two tit species in a Mediterranean forest. Our results showed that blue tit feeding rates were higher than those of great tits, probably to compensate for the smaller prey delivered to nestlings by blue tits. Blue tits brought more spiders than great tits, while grey tits brought larger prey and more caterpillars. This may be because larger great tits can prey upon larger prey items than blue tits. As a main result, this study supports the view of resource partitioning by great and blue tits in sclerophyllous Mediterranean forest ecosystem.
Research Interests:
Male colouration has a key role in signalling individual quality during the breeding season. Although winter plumage probably correlates with of summer plumage, few studies have focused on the determinants of male colouration during the... more
Male colouration has a key role in signalling individual quality during the breeding season. Although winter plumage probably correlates with of summer plumage, few studies have focused on the determinants of male colouration during the non-breeding period. If plumage colouration is related to an individual's age or is strongly correlated with body condition during the non-breeding period, this trait could be used by conspecifics to assess quality, origin or status of a given individual. Here, we analysed plumage colouration and body size of male Bluethroats (Luscinia svecica cyanecula) wintering in SE Iberia. We found that young individuals had narrower black bands and wider white bands than adult individuals in their throat patch. Also, the width of the chestnut band increased with later capture date. Finally, blue throat colouration was positively correlated with tail length and negatively correlated with tarsus length. We could not find any significant relationship between throat patch colouration and body mass. We concluded that individual's age and capture date were significantly related to black and chestnut throat colouration, respectively. Therefore, these coloured bands could provide reliable cues on individual's age and their geographical origins. The variability of plumage colouration of wintering Bluethroats provides an excellent study system in which to test further hypotheses on the role of the throat patch colouration outside the breeding season.
Research Interests:
Carotenoid-based coloration of nestling plumage is generally considered a reliable signal of quality and has consistently been related to habitat structure. The main hypothesis proposed to explain this correlation is that high quality... more
Carotenoid-based coloration of nestling plumage is generally considered a reliable signal of quality and has consistently been related to habitat structure. The main hypothesis proposed to explain this correlation is that high quality habitats contain high quality food, which in return affects the expression of carotenoid-based plumage. It therefore assumes that, at the population level, the link between habitat structure and food composition is consistent and more relevant than inter-individual differences in foraging ability or parental investment. In addition, it is assumed by default that food and habitat produce concordant effects on nestling coloration. In this work we evaluated habitat structure and prey composition in addition to several measures of parental investment. We investigated their relative effect on carotenoid-based plumage coloration (lightness, chroma and hue) of great tit Parus major nestlings. We found a low correlation between carotenoid-based coloration of nestlings and that of their parents. Nestling coloration, especially lightness and chroma, increased with the intake of more spiders. The time of breeding was positively correlated with lightness and chroma and negatively correlated with hue. Finally, the maturity of oak trees surrounding nest-boxes correlated negatively with lightness, and the size of all tree species surrounding nest-boxes correlated positively with hue of chick plumage. Our findings support the view that habitat structure and prey composition may produce divergent effects on feather pigmentation, and that prey proportions and variables related to parental investment should be assessed when considering carotenoid-based coloration of chicks.
Research Interests:
A key topic in foraging ecology is whether a particular prey type is consumed because it is more abundant or easier to catch, or because there is a specific preference for it. The great tit Parus major is an ideal species for studying... more
A key topic in foraging ecology is whether a particular prey type is consumed because it is more abundant or easier to catch, or because there is a specific preference for it. The great tit Parus major is an ideal species for studying this topic. Although it is traditionally regarded as a caterpillar specialist, in certain periods, e.g. during the breeding season, or areas, such as the Mediterranean forests, the great tit seems to show a preference for spiders. We conducted food choice experiments with captive birds to ascertain which of these two main prey types (caterpillars vs. spiders) was preferred outside the breeding season when there was an opportunity to prey on both food types. In conclusion, we found that, regardless of any variation in the supply-demand ratio and the amount of food available, Mediterranean
great tits showed a preference for spiders.
great tits showed a preference for spiders.
Research Interests:
Capsule The pattern of moult of juvenile Common Chiffchaffs (Phylloscopus collybita) wintering in two distant localities of the Iberian Peninsula, Málaga (south) and Barcelona (north) differed. Individuals wintering in the northern... more
Capsule The pattern of moult of juvenile Common Chiffchaffs (Phylloscopus collybita) wintering in two distant localities of the Iberian Peninsula, Málaga (south) and Barcelona (north) differed. Individuals wintering in the northern locality moulted more contour than flight feathers, and vice versa, while sexes did not differ; individuals moulting more contour feathers arrived later and individuals moulting more flight feathers arrived earlier. Taken together, our results suggest that the pattern of moult of juvenile Common Chiffchaffs may depend on the location to which they migrate, in addition to the geographic origin and the time of breeding.
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Parental investment is a key topic in avian ecology, and many authors have focused on nestling-feeding behaviour to analyse this issue. Surprisingly, most studies have based their results on feeding patterns recorded over periods of only... more
Parental investment is a key topic in avian ecology, and many authors have focused on nestling-feeding behaviour to analyse this issue. Surprisingly, most studies have based their results on feeding patterns recorded over periods of only one or two hours, possibly leading to over generalizations regarding temporal-dependent behavioural patterns. Irrespective of nestling age or brood size, if we use observations from such short periods as conclusive evidence we must assume that parents behave consistently across time and that the window of time selected is representative of parental effort. To test this assumption, we analysed the time consistency of nestling provisioning rates and prey composition of 32 breeding pairs of Mediterranean Great Tits Parus major, from dawn to midday (7 hours recording). Regardless of a parallel decrease in the intensity of work for both sexes, we found that hourly provisioning rates per nestling correlated strongly with the mean number of feedings per nestling and per hour recorded over the whole 7 hours of recording. Weather conditions and nestling age had no effect on hourly provisioning rates per nestling, although parents with older nestlings worked relatively less hard. We also observed that the peak of morning activity was higher in nests with small clutches. Prey proportions showed a high degree of temporal repeatability, but nestling diet composition should be studied with caution. Although prey composition was stable over time, we recorded a strong decrease in the number of prey items delivered by parents throughout the day, along with an increase in prey size. We thus recommend using a wider time window to obtain reliable results when studying prey composition. In any case, considering our results, one hour of recording may be sufficient to describe nestling-feeding behaviour of Great Tit parents.
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Given the known influence of parental investment on breeding success of great tits Parus major, females should be expected to use male parental quality as an essential criterion in mate choice. Since parental quality cannot usually be... more
Given the known influence of parental investment on breeding success of great tits Parus major, females should be expected to use male parental quality as an essential criterion in mate choice. Since parental quality cannot usually be observed directly at the time of pairing, it has been suggested that females rely on male ornaments as indicative of their ability to provide parental care. This hypothesis, called the good parent hypothesis, has been tested repeatedly assessing only parental effort as the number of feedings made by parents. However, in evaluating parental investment, the focus should also be on the quality of prey captured rather than only on its quantity. We analyzed feeding rates and the provisioning of different prey in relation to both male yellow carotenoid-based breast coloration and the size of the black melanin-based stripe in a Mediterranean great tit population. We predicted that more carotenoid ornamented individuals would feed nestlings with a diet consisting of a higher proportion of caterpillars. However, and contrary to predictions, we found that males with higher values of hue in the yellow breast feathers, fed their offspring with a lower proportion of caterpillars and a higher proportion of spiders. In addition, nestlings that received a higher proportion of spiders showed an improved body condition after controlling for tarsus length and other variables. Male feeding rates correlated positively with brood size and tended to correlate negatively with date, although we did not find any effect of male coloration. Our data therefore support the good parent hypothesis, insofar as parental investment is also a matter of quality, and that, at least in the Mediterranean area, caterpillars are not the only key food source.
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Yearling birds generally display duller colours than adults. This may be due to selection favouring birds with more intensely coloured plumage or to an increase in colour after the first complete moult. Most research to date on the topic... more
Yearling birds generally display duller colours than adults. This may be due to selection favouring birds with more intensely coloured plumage or to an increase in colour after the first complete moult. Most research to date on the topic has been carried out on species with structural plumage coloration or with carotenoid-based coloration that is produced by the unmodified deposition of pigments. However, no study has been carried out on species whose carotenoids are metabolically modified before deposition. In this study, we assess age-related changes in the carotenoid-based coloration of European Serins, a species that metabolically processes carotenoids before they can be deposited into feathers. Birds were captured over consecutive years and we carried out both cross-sectional and longitudinal analysis. Adults had significantly greater values of lightness and chroma than yearling birds. However, there were no changes in plumage colour when analysing the same individuals captured in subsequent seasons. Plumage lightness and chroma of adult males after moult were related to body mass, suggesting a role of body condition on plumage coloration. Our results suggest that changes in plumage coloration with age in European Serins are due to a selection process that favours more intensely coloured individuals.
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Capsule The Red-billed Leiothrix (Leiothrix lutea) is a superficially sexually monochromatic colourful bird native to the Indian subcontinent, which has colonized many locations across the world as an introduced species. We investigated... more
Capsule The Red-billed Leiothrix (Leiothrix lutea) is a superficially sexually monochromatic colourful bird native to the Indian subcontinent, which has colonized many locations across the world as an introduced species. We investigated the best method to accurately sex the species, capturing and measuring the colour and external morphometry of a sample of 57 individuals, which were later sexed molecularly from blood samples. We found that sexes showed no dimorphism in biometry or size of wing coloured-patches. However, a Discriminant Function based on hue of the throat, chroma of the crown and lightness of the breast allowed us to determine sex with an accuracy of 91%.
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The diet of the Great Tit Parus major when rearing chicks has been described in many studies. However, data from the Mediterranean area is scarce. Here we describe the diet of nestlings in a population of Great Tits in a Mediterranean... more
The diet of the Great Tit Parus major when rearing chicks has been described in many studies. However, data from the Mediterranean area is scarce. Here we describe the diet of nestlings in a population of Great Tits in a Mediterranean forest in Barcelona (north–east Spain) during two breeding seasons using two methods: neck–collarsand video recording. The main prey were caterpillars (44% from neck–collar data and 62% from video–recorded data), but in our latitudes spiders also seemed to be an important food resource (24% from neck–collar data and 42% from video–recorded data). We did not find any significant differences in the quantity of spiders collected by parents in relation to stage of chick development, main vegetation surrounding nest boxes, size of the brood, or year. Our results stress the importance of spiders as a food source in Mediterranean habitats.
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Inter-individual differences in the extent of post-juvenile moult of migratory birds are usually attributed to energetic or time constraints related to different geographic origins. In addition to these factors, recent research has... more
Inter-individual differences in the extent of post-juvenile moult of migratory birds are usually attributed to energetic or time constraints related to different geographic origins. In addition to these factors, recent research has stressed the importance of food availability for the process of moult and the migratory strategy of individuals. Consequently, individual quality and foraging ability would account for both moult extension and body condition. We hypothesized that both variables may be influenced by the same factors and would be correlated in winter. We therefore tested whether the extent of post-juvenile moult was associated with body condition (body mass, muscle and fat scores) and related variables (tarsus and bill length) of forty-six Common Chiffchaff Phylloscopus collybita males wintering in the Mediterranean area. We found no correlation between moult extension and body mass. Nevertheless, Common Chiffchaffs with longer bills and that showed a higher fat score were in better body condition and moulted a larger number of flight feathers. The number of flight and contour feathers moulted increased as the season proceeded, whereas body mass varied on a daily temporal scale. Our results support the idea that individual quality influences post-juvenile moult and winter performance, and suggest that juvenile Common Chiffchaffs with longer bills may display different foraging strategies that lead some individuals to improve their performance.
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Animal research commonly requires temporary handling of study animals. In this study, we compared the response to handling stress in urban and forest Great Tits (Parus major). We measured breath rate, which has been suggested as a proxy... more
Animal research commonly requires temporary handling of study animals. In this study, we compared the response to handling stress in urban and forest Great Tits (Parus major). We measured breath rate, which has been suggested as a proxy of the stress response of the bird. Urban birds displayed higher breath rates than forest birds. Results suggest that the effect of handling can vary from one habitat to another and should be taken into account in future studies on the topic.
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Metals are naturally found in the environment but are also emitted through anthropogenic activities, raising some concerns about the potential deleterious effects of these elements on wildlife. The potential effects of metals on bird... more
Metals are naturally found in the environment but are also emitted through anthropogenic activities, raising some concerns about the potential deleterious effects of these elements on wildlife. The potential effects of metals on bird coloration have been the focus of several recent studies since animal colored-signals often reflect the physiology of their bearers and are thus used by animals to assess the quality of another individual as a mate or competitor. These studies have shown that the melanin pigmentation seems to be positively associated and the carotenoid-based coloration negatively associated with metal exposure in wild birds. Although these studies have been very useful to show the associations between metal exposure and coloration, only few of them have actually quantified the levels of metals exposure at the individual level; always focusing on one or two of them. Here, we measured the concentrations of eight metals in great tits’ feathers and then assessed how these levels of metals were associated with the carotenoid and melanin-based colorations. We found that the melanin pigmentation was positively associated with the copper concentration and negatively correlated with the chromium concentration in feathers. In addition, we have shown that the carotenoid-based coloration was negatively associated with the feather’s mercury concentration. This study is the first one to identify some metals that might affect positively and negatively the deposition of melanin and carotenoid into the plumage of wild birds.