Seabirds

Zooplanktivorous seabirds as central-place foragers are constrained by the need to repeatedly return to the colony. Breeding within a cost-effective distance from food-abundant foraging grounds may be crucial for successful reproduction. In this study, foraging areas, ranges and habitats of high-Arctic little auks ( Alle alle) breeding on Bjørnøya in the Barents Sea, at the southern edge of their breeding range, were investigated combining GPS-tracking and satellite remote sensing. Birds were expected to forage in areas with productive oceanographic features (cold shelf and frontal zone waters) close to their breeding colony. Contrary to expectation, they foraged in warm waters (sea surface temperature median 6.6 °C), optimal for boreal zooplankton. Little auks preferred shallow shelf waters (mean depth 74 m) characterized by higher chlorophyll a concentrations. Parent birds performed both short (ST) and long (LT) foraging trips, both of considerably longer duration compared to other colonies in more high-Arctic environment. During ST they probably spent more time searching for preferred Arctic prey (dominating in chick diet samples) among abundant Atlantic zooplankton. Long duration of LT resulted from exploring distant cold waters abundant in Arctic zooplankton community. This confirms that little auks are able to respond to various environmental conditions through the plasticity of their foraging behavior without negative consequences for chick survival. To date, observed changes in marine environment have not posed a threat to the ability of little auks on Bjørnøya to feed their chicks energy-rich zooplankton.

Many animals reproduce in large aggregations, which can vary in size from dozens to millions of individuals across species, time and space. The size of breeding colonies is a complex trade-off between multiple costs and benefits to an individual’s fitness, but the mechanisms by which colony size affects fitness are still poorly understood. One important cost of breeding in a large colony is the spatial constraint in resource use due to the need to regularly return to a central location. Large aggregations, like seabird breeding colonies, may therefore deplete food resources near the colony, forcing individuals to travel farther to find food, which may ultimately limit their reproductive output and population size. This hypothesis, proposed in 1963 by Ashmole for tropical oceanic islands, has so far not been tested at tropical seabird colonies, where food availability is less predictable than in colder waters. We compare the foraging distribution of a common tropical seabird, the masked booby Sula dactylatra, breeding on two islands in the South Atlantic that differ in the size of the breeding seabird community by 2 orders of magnitude, but are surrounded by similar oligotrophic waters. Foraging trips from the island with the smaller colony were on average 221 km (61 %) and 18.0 h (75 %) shorter because birds from the smaller colony rarely spent the night at sea and foraged on average 64 km (46 %) closer to the colony. Energy expenditure was significantly lower, and nest survival higher (47 vs. 37 %, n = 371) on the island with the smaller colony. These results are fully consistent with the predictions from Ashmole’s hypothesis and indicate that competition for food around tropical oceanic seabird colonies may indeed be a limiting factor for populations. Identifying important feeding areas for seabirds based on their foraging range may need to account for colony size of both the target and potential competitor species.

In order to assess the potential impacts of multiple wind farms within the Dutch North Sea
on bird populations, a two-step modelling approach was applied: Step one involved
constructing matrix-based population models for bird species occurring within the Dutch
North Sea. Step two involved assessing the effects of increased mortality on these
populations. The bird populations assessed included both seabirds and coastal species
breeding around the North Sea region, as well as key passage migrants from a wider area.
Two wind farm scenarios were modeled in order to provide estimates of the potential impact
of mortality due to collisions (which was considered to have a far greater influence on
mortality than disturbance or barrier effects in the specific Dutch situation). Field data
collected with radar and visual observations at the OWEZ wind farm helped to inform these
models. The additional mortality was then applied to the population models. For those
species that are currently stable or increasing, the influence of this additional mortality was
very limited. Also for the species currently in decline the additional mortality contributed little
to these trends.

Population size assessments for nocturnal burrow-nesting seabirds are logistically challenging because these species are active in colonies only during darkness and often nest on remote islands where manual inspections of breeding burrows are not feasible. Many seabird species are highly vocal, and recent technological innovations now make it possible to record and quantify vocal activity in seabird colonies. Here we test the hypothesis that remotely recorded vocal activity in Cory’s shearwater (Calonectris borealis) breeding colonies in the North Atlantic increases with nest density, and combined this relationship with cliff habitat mapping to estimate the population size of Cory’s shearwaters on the island of Corvo (Azores). We deployed acoustic recording devices in 9 Cory’s shearwater colonies of known size to establish a relationship between vocal activity and local nest density (slope = 1.07, R2 = 0.86, p < 0.001). We used this relationship to predict the nest density in various cliff habitat types and produced a habitat map of breeding cliffs to extrapolate nest density around the island of Corvo. The mean predicted nest density on Corvo ranged from 6.6 (2.1–16.2) to 27.8 (19.5–36.4) nests/ha. Extrapolation of habitat-specific nest densities across the cliff area of Corvo resulted in an estimate of 6326 Cory’s shearwater nests (95% confidence interval: 3735–10,524). This population size estimate is similar to previous assessments, but is too imprecise to detect moderate changes in population size over time. While estimating absolute population size from acoustic recordings may not be sufficiently precise, the strong positive relationship that we found between local nest density and recorded calling rate indicates that passive acoustic monitoring may be useful to document relative changes in seabird populations over time.

Industrial fishing can profoundly alter marine environments, and no-take zones are an important tool to achieve sustainable fishing and re-establish ecosystem integrity. However, the potential benefits for vagile species such as top predators are still questioned. The numbers of endangered African penguins Spheniscus demersus have halved since 2004. They depend on small pelagic fish, also targeted by a purse-seine industry in South Africa. We studied penguin foraging behaviour and breeding output at two colonies supporting 60% of the global population in relation to fishing activity by purse-seine vessels. In 2008, both sites were open to fishing, but in 2009 and 2010 waters within 20 km of the world’s largest colony were closed to fishing, while waters around the neighbouring colony, 50 km away, remained open. Birds’ foraging effort increased with the size of catches around their colonies and decreased with the implementation of a reserve. Total fishing catches in the bay remained constant, but shifted toward the boundaries of the reserve in 2010. While the no-take zone significantly reduced penguin foraging effort, intensified fishing pressure at the reserve boundaries (“fishing the line”) in 2010 limited this benefit. The decrease over time of both adult body mass and chick growth rates from both colonies, suggested that the 20 km-closure is too small to reverse penguin population decreases. Therefore, stronger fishery management measures, such as larger no-take zones, buffer zones around reserves, or local reduction of fishing quotas, seem necessary to increase food availability for penguins around their colonies. The collapse of Africa’s only breeding penguin species adds urgency to the wider implementation of such measures.

Both survival and reproduction are important fitness components, and thus critical to the viability of wildlife populations. Preventing one death (survival) or contributing one newborn (reproduction), has arguably the same effect on population dynamics-in each instance the population grows or is maintained by one additional member. However, for the conservation of slow-growing animal populations, the importance of reproduction is sometimes overlooked when evaluating wildlife management options. This has to do with the use of demographic sensitivity analyses, which quantify the relative contribution of vital rates to population growth. For slow-growing populations, the results of such analyses typically show that growth rates are more sensitive to changes in survival than to equal proportional changes in reproduction. Consequently, for slow-growing taxa, survival has been labelled a better fitness surrogate than reproduction. However, such a generalization, derived from conventional sensitivity analyses, is based on flawed approaches, such as omitting appropriate scaling of vital rates, and sometimes misinterpretations. In this chapter, I make the case that for the conservation of slow-growing species the role of reproduction is considerably greater than conventional sensitivity analyses would suggest. This is illustrated by case studies on wildlife populations that underscore the importance of reproduction for the conservation of slow-growing birds, ungulates, carnivores, and cetaceans.

Since the first version of this account was published in 2002, important new information has been generated on the population genetics of Common Terns (see Systematics), migration patterns and overwintering areas (see Migration), chick growth (see Breeding), adult survival and breeding dispersal (see Demography). Much new information has been generated on the distribution of boreal populations in Canada away from large lakes and on other aspects of the ecology of inland populations (see Habitat, Breeding, and Demography). Declines in numbers breeding in the Great Lakes and the large lakes of Manitoba, combined with genetic evidence for asymmetric gene flow towards coastal populations and with the generally low reproductive success at inland colonies (see Systematics, Breeding, and Demography), have led to increased concern for the conservation status of many inland populations. The history of recent successes and failures in managing and restoring breeding colonies shows that North American Common Terns are heavily dependent on restored and artificial sites, and require continuing management (see Conservation). This revision also updates information on the numbers and trends in many regional and local populations, and on reproductive success at many breeding colonies throughout the southern part of the continental range (see Appendices).

Prebreeding, subadult seabirds have been documented prospecting or visiting multiple sites throughout the breeding season to gather information on colony reproductive success, identify suitable habitat, evaluate prey abundance, and locate potential partners; however, many aspects of prospector biology remain unknown. We explored prospector behaviour as a means of furthering our understanding of postnatal seabird dispersal and colony attendance using Least Auklets (Aethia pusilla (Pallas, 1811)) and Crested Auklets (Aethia cristatella (Pallas, 1769)) breeding at Gareloi Island, Alaska, in 2014 and 2015. We recorded age class, length of time spent on the colony, and behaviour for individuals attending a study plot over the course of two breeding seasons. Although prospectors typically spent more time on the colony surface than adults, prospectors rarely socialized with conspecifics during their visits to the colony, possibly due to the absence of a citrus-like feather odour used in olfactory communication. Additionally, we found substantial differences between observed and predicted data between years, demonstrating that other factors (likely prey abundance or quality) influenced behaviour in 2015. Our results suggest that the collective knowledge of seabird prospecting behaviour is not necessarily transferable between taxa and there may be a range of strategies employed by prospectors when assessing colonies. Résumé : Si des oiseaux marins préreproducteurs et subadultes ont été documentés en train de prospecter ou de visiter différents sites durant toute la saison de reproduction afin de recueillir de l'information sur le succès de reproduction de la colonie, cerner des habitats convenables, évaluer l'abondance de proies et localiser des partenaires potentiels, de nombreux aspects de la biologie des prospecteurs demeurent toutefois inconnus. Nous avons exploré le comportement de prospection afin d'accroître la compréhension de la dispersion post-natale et de la fréquentation des colonies par les oiseaux marins en observant des stariques minuscules (Aethia pusilla (Pallas, 1811)) et stariques cristatelles (Aethia cristatella (Pallas, 1769)) nidifiant dans l'île Gareloi (Alaska), en 2014 et 2015. Nous avons enregistré la classe d'âge, le temps passé dans la colonie et le comportement pour des individus fréquentant une parcelle étudiée durant deux saisons de reproduction. Si les prospecteurs passaient typiquement plus de temps a ` la surface de la colonie que les adultes, ils ne nouaient que rarement contact avec des conspécifiques durant leurs visites a ` la colonie, possiblement en raison de l'absence de l'odeur des plume s'apparentant a ` celle d'agrumes utilisée dans la communication olfactive. Nous avons en outre noté d'importantes différences entre les données observées et prédites d'une année a ` l'autre, ce qui démontre que d'autres facteurs (vraisemblablement l'abondance ou la qualité des proies) influençaient le comportement en 2015. Nos résultats donnent a ` penser que les connaissances collectives associées au comportement prospec-teur des oiseaux marins ne sont pas nécessairement transférables entre taxons et que les prospecteurs pourraient faire appel a ` un éventail de stratégies pour évaluer les colonies. [Traduit par la Rédaction] Mots-clés : stariques Aethia, signaux de conspécifiques, starique minuscule, Aethia pusilla, starique cristatelle, Aethia cristatella, écologie post-natale des oiseaux marins, décisions de recrutement et d'établissement, socialité.

Updates from the WCS’s Bronx Zoo, Ornithology Department are reported here.  Significant avian propagation efforts include Lesser Adjutant Storks, Blue-billed Curassow, Maleo, Band-tailed Pigeon and African Pygmy Geese.  Conservation features involving the Papua New Guinea program, Black-browed Albatross, in Chile and programs to assist the North American population of Trumpeter Swans.  Other articles describe archive efforts, staff mentoring students and new animals at the Bronx and Queens Zoos.

Abstract. Fisheries bycatch, or incidental take, of large vertebrates such as sea turtles, seabirds, and marine mammals, is a pressing conservation and fisheries management issue. Identifying spatial patterns of bycatch is an important element in managing and mitigating bycatch occurrences. Because bycatch of these taxa involves rare events and fishing effort is highly variable in space and time, maps of raw bycatch rates (the ratio of bycatch to fishing effort) can be misleading. Here we show how mapping bycatch can be enhanced through the use of Bayesian hierarchical spatial models. We compare model-based estimates of bycatch rates to raw rates. The model-based estimates were more precise and fit the data well. Using these results, we demonstrate the utility of this approach for providing information to managers on bycatch probabilities and cross-taxa bycatch comparisons. To illustrate this approach, we present an analysis of bycatch data from the U.S. gill net fishery for groundf...

Se presentan los primeros restos diagnósticos asignables a Spheniscus megaramphus procedentes del Miembro Bonebed de la Formación Bahía Inglesa (Mioceno tardío), consistentes en tres rostros aislados pertenecientes a la colección del Museo Paleontológico de Caldera, Chile. Se rectifica la antigüedad de la especie en el Perú, previamente asociada al Mesiniano (6 Ma) y actualmente referida al Tortoniano (9.5-9 Ma). El presente estudio confirma la existencia de esta especie en Chile, ampliando el rango de incidencia de la especie hasta los 27º S durante el Mioceno tardío. ABSTRACT The first diagnostic remains assignable to Spheniscus megaramphus coming from the Bonebed Member of the Bahia Inglesa Formation (Late Mioceno) are presented. These consist of three isolated rostrums from the collection of the Museo Paleontologico de Caldera, Chile. The antiquity of the species is rectified in Peru previously associated to the Mesinian (6 My) and at the moment referred to the Tortonian (9.5-9 My). The present study confirms the existence of this species in Chile enlarging the range of incidence of the species until the 27º S during the Late Miocene.

Birds are vectors of dispersal of propagules of plants and other organisms including pathogens, as well as nutrients and contaminants. Thus, through their movements they create functional connectivity between habitat patches. Most studies on connectivity provided by animals to date have focused on movements within similar habitat types. However, some waterbirds regularly switch between terrestrial, coastal and freshwater habitats throughout their daily routines. Lesser black-backed gulls that overwinter in Andalusia use different habitat types for roosting and foraging. In order to reveal their potential role in biovectoring among habitats, we created an inter-habitat connectivity network based on GPS tracking data. We applied connectivity measures by considering frequently visited sites as nodes, and flights as links, to determine the strength of connections in the network between habitats, and identify functional units where connections are more likely to happen. We acquired data for 42 tagged individuals (from five breeding colonies), and identified 5676 direct flights that connected 37 nodes. These 37 sites were classified into seven habitat types: reservoirs, natural lakes, ports, coastal marshes, fish ponds, rubbish dumps and ricefields. The Doñana ricefields acted as the central node in the network based on centrality measures. Furthermore, during the first half of winter when rice was harvested, ricefields were the most important habitat type in terms of total time spent. Overall, 90% of all direct flights between nodes were between rubbish dumps (for foraging) and roosts in other habitats, thereby connecting terrestrial and various wetland habitats. The strength of connections decreased between nodes as the distance between them increased, and was concentrated within ten independent spatial and functional units, especially between December and February. The pivotal role for ricefields and rubbish dumps in the network, and their high connectivity with aquatic habitats in general, have important implications for biovectoring into their surroundings.

Birds are fauna that are widely spread from the coast and the sea to the tops of mountains. Spatial use of birds is related to habitat use in accordance with the preferences of each species. Ujung Pangkah is one of the coastal areas in Gresik Regency, East Java and is the estuary of the Bengawan Solo River. This region has extensive mangrove and mudflat habitats. In addition, this region also consists of islands which are formed from sediments of mud which become arising land. Space utilization of birds is closely related to the type of feed, the level of disturbance, and other activities. Ujung Pangkah also serves as a transit area for migratory birds, especially coastal and marine birds. In this study, spatial utilization patterns are needed to map the areas used by birds in their activities. The purpose of this study is to identify and calculate the value of bird diversity and mapping the pattern of spatial use along with the habitat types used. The study was conducted in October-November 2016 in three zones, namely the northern zone, eastern zone and western zone. The investigation was carried out with exploration methods at each observation point. The results showed the diversity of birds in the Ujung Pangkah area consisted of 59 species from 27 families. The species of Common Sandpiper (Actitis hypoleucos) is a bird that uses the most extensive space and found in all study area. Habitat used is quite diverse that is mudflat, mangroves, ponds and residential areas.

Animal‐attached technologies can be powerful means to quantify space‐use and behaviour, however, there are also ethical implications associated with capturing and instrumenting animals. Furthermore, tagging approaches are not necessarily well‐suited for examining the movements of multiple individuals within specific, local areas of interest. Here, we assess a method of quantifying animal space use based on a modified theodolite with an inbuilt laser rangefinder. Using a database of > 4,200 tracks of migrating birds, we show that detection distance increases with bird body mass (range 5 g – >10 kg). The maximum distance recorded to a bird was 5500 m and measurement error was ≤ 5 m for targets within this distance range; a level comparable to methods such as GPS tagging. We go on to present a case study where this method was used to assess habitat selection in seabirds operating in dynamic coastal waters close to a tidal turbine. Combining positional data with outputs from a hydrographic model revealed that great cormorants (Phalacrocorax carbo) appeared to be highly selective of current characteristics in space and time; exploiting areas where mean current speeds were < 0.8 m s−1, and diving at times when turbulent energy levels were low. These birds also orientated into tidal currents during dives. Taken together, this suggests that collision risks are low for cormorants at this site, as the two conditions avoided by cormorants (high mean current speeds and turbulence levels), are associated with operational tidal turbines. Overall, we suggest that this modified theodolite system is well‐suited to the quantification of movement in small areas associated with particular development strategies, including sustainable energy devices.

Introduction: I here comment on the phylogenetic position and generic status of the rare and threatened Abbott's Booby Papasula abbotti. I argue that the current genus name of this species was erected from an incorrect interpretation of a phylogenetic hypothesis and a straightforward decision about its generic placement cannot be made, given the conflicts regarding the species' closer phylogenetic relationships.

Pulau Ling is a small rocky island located to the south of Pulau Redang, forming with other southeast small islands, the Redang Archipelago, in the state of Terengganu, Malaysia. The island was highlighted in
the early 1950s as an important seabird site, although little was then known on the status of seabirds on the island. Field visits were made between May 2015 and September 2015 to assess the importance of
this small island to seabird species. Four tern species were identified: two of them, black-naped tern Sterna sumatrana and bridled tern Onychoprion anaethetus, were found to breed there, while the other
two species, great crested tern Thalasseus bergii and roseate tern Sterna dougallii were found to use the island as a stopover site without any evidence of breeding. Furthermore, the Pacific Eastern Reef egret
Egretta sacra (the black morph), was also found to breed on the island. Other species encountered included white-bellied sea eagle Haliaeetus leucogaster (recorded once in June 2015, soaring over the island). These preliminary data show the importance of such small rocky outcrops for tropical breeding and migrating seabirds, where food availability and lack of disturbance may be the two main drivers for
diversity and survival.

Egg composition varies both within and between clutches, and mothers are expected to alter their deposition of resources to the egg depending on environmental conditions and breeding strategies. Within-clutch variation in egg composition has been proposed to reflect an adaptive maternal strategy influencing sibling competition. In species with brood reduction, mothers should reinforce brood hierarchies due to hatching asynchrony and favour senior chicks by making first-laid eggs larger, richer in nutrients, with higher testosterone and carotenoid levels and lower corticosterone concentrations than last-laid eggs [parental favouritism hypothesis (PFH)]. Moreover, mothers that are of better quality and/or experience better feeding conditions during laying are expected to increase their deposition of resources to the egg, resulting in differences between clutches [investment hypothesis (IH)]. Several components may act together to provide an optimal reproductive strategy, but studies of variation in different egg components in the same egg are relatively rare. We analysed egg size, testosterone and corticosterone concentrations and carotenoids measured as yolk colour between and within clutches for the facultative siblicidal Black-legged Kittiwake Rissa tridactyla. First-laid eggs were larger, contained lower testosterone, higher yolk colour score, and similar corticosterone levels than last-laid eggs. Thus, only differences in egg size and yolk colour supported the PFH. We used within-clutch egg size dimorphism as an indicator of the quality of the mother or the feeding conditions during laying. In support of the IH, we found that mothers of better quality or that experienced better feeding conditions deposited more corticosterone into their eggs. High corticosterone levels may benefit nestlings when there is no brood reduction but high sibling competition is present. We found no support for the hypothesis that egg components are mutually adjusted to each other and we discuss the possible reasons for this.