Seabirds

In marine ecosystems, predators can affect community and ecosystem dynamics through a variety of processes such as foraging facilitation. Here, we report evidence of foraging facilitation between common bottlenose dolphins (Tursiops truncatus) and double-crested cormorants (Nannopterum auritum) in the Caribbean seagrass-dominated atoll of Turneffe, Belize using aerial drone observations conducted in 2015-2017. While dolphins exhibited occasional aggressive behaviours toward the cormorants, the latter frequently followed dolphin movements, suggesting opportunistic pursuit of dolphins for prey access during dolphin bottom foraging activity. Our observations underscore the intricate ecological relationships among marine predators and highlight the need to quantify the mutual benefits and costs of such interactions as coastal ecosystems are rapidly changing.

En el marco del proceso de litoralización económica vivido durante el siglo XIX y tomando el sur andino, en este caso las zonas costeras del Perú y Bolivia, como área de estudio, en el artículo presente se trata de destacar las estrategias de distintos actores políticos y económicos (Estado, empresas de capital internacional, intermediarios locales) para con el guano. A través del estudio de documentación ejecutiva, legislación y los libros de cuentas de la empresa inglesa Gibbs Crawley Co., la acción de la cual fue central para la explotación guanera inicial, se concluye afirmando el peso específico del guano para la formación de polos económicos de importancia en las costas de ambos países que progresivamente diezmaron el calibre de la recaudación interior (para la hacienda, sobre todo peruana) o replanificaron los proyectos nacionales (viéndose un giro hacia los orientes bolivianos), pero en todo caso dieron paso al asentamiento de la frontera económica capitalista en regiones otrora desérticas.

The imperial cormorant (Phalacrocorax atriceps) is one of the most abundant cormorant species in the Chilean channels and fjords. Although its reproductive and non-reproductive distributions have been studied, works on its diet are inexistent. This paper describes the diet and determines the dominance and diversity of the prey consumed during the winter periods of 2011 and 2014 in Caulín Bay, Chiloé, southern Chile. A total of 73 pellets were collected (30 in 2011 and 43 in 2014). Prey were identified and classified into three categories: fishes (53.57%), cephalopods (39.29%) and crustaceans (7.14%). When prey consumption was analyzed according to their distribution in the water column, we observed statistically significant differences in a preference of benthic demersal over pelagic prey.

The Imperial Cormorant (Phalacrocorax atriceps) is a endemic seabird of Patagonia. Despite being one of the most abundant seabird species of channels and fjords of southern Chile, little is known of its breeding distribution and population. Through a review of literature and unpublished data, this work presents a list of nesting sites of the Imperial Cormorant on the Chilean coast and makes a diagnosis of their population status. Our review identified 42 colonies along the Chilean coast, from Santa Maria Island (37ºS) to the islands of Diego Ramirez (56ºS). Colony sizes range from 50 to 8,000 pairs, but the type of information collected in several cases does not allow a reliable population estimate for Chile. We recommend increasing the efforts in the development of research projects focusing on the distribution and abundance of nesting sites of this and other seabird species in southern Chile. Manuscrito recibido el 01 de diciembre de 2009, aceptado el 30 de junio de 2010. Editor a...

Successful conservation depends on an understanding of dispersal patterns for spatially complex species. Among seabirds there are opposing pressures to either disperse or return to natal colonies. We explored philopatry across 36 species, based on banding and census data. Philopatry correlated with foraging strategy, taxonomy, and region, suggesting that translocation will be more successful for Procellariiformes, those in tropical regions and with non-central foraging strategies, as they are more likely to return to translocation sites. Additionally, we compared genetic diversity between two orders of seabirds with differing philopatry and explored population genetics of a species in the order Procellariiformes, the Band-rumped Storm Petrel (BSTP; Oceanodroma castro). Findings indicated no difference in genetic diversity between orders and high genetic diversity within BSTP. Although this study suggests that BSTP are not at risk genetically, they remain vulnerable to threats. Manag...

Rynchops albicollis is an Endangered riverine bird that is undergoing rapid population decline (Birdlife International 2023). We report two records of Indian Skimmer on the Gomti River of Uttar Pradesh and discuss its potential for breeding. In India, the Skimmers are confined to large river systems but also occur in Bangladesh, Pakistan, and some countries in Southeast Asia, such as Myanmar, Cambodia, Laos, and Vietnam. It is now considered extinct in the Mekong Delta in Vietnam, is a rare visitor to Nepal, and has also been recorded in China (Sundar 2004). Indian Skimmers are gregarious and colonial and are often found in flocks (Rajguru 2017). We recorded a flock of 57 Indian Skimmers resting on a small sandy island on the Gomti River near Palauli (26.66°N, 81.44°E) on 28 February 2022. We observed the flock on three days in the same location during that month. We also observed small shallow depressions on the ground that might have been their attempts to breed. On 07 March 2022, a single skimmer was observed downstream, which is aerially c.14 km along the channel near a location called Devait (26.67°N, 81.56°E), as it skimmed over the water surface. Hence, it is possible that there are similar islets on the river, which might offer possible breeding sites. However, we observed high levels of human interference on the riverscape and sandy islands during the survey. As this river flows through a highly agriculture-dependent area, various activities, such as water extraction, fishing, cattle grazing, sand mining, and other activities, were observed. Such a high rate of disturbance from humans and livestock is a major threat to riverine nesting birds, and hence, the chances of successful breeding are bleak (SoIB 2023). The important river systems for the Indian Skimmer in India are Chambal, Ganga, Mahanadi, Yamuna, and Son (SoIB 2023). The Gomti River is one of the important tributaries of the Ganga River, originating from the Pilibhit district and confluences with Ganga in the Ghazipur district, covering c.835 km. The river drains the areas between the Ramganga and Sharda Rivers in the upper region and the Ganga and Ghagra Rivers in the lower region. Historically, there have been very few records of Indian Skimmer from the Gomti River. BirdLife International (2001) quotes a record by Jesse from the Lucknow region on Gomti from 1902. Since then, no other Indian Skimmer has been reported from this particular river based on a literature survey (Islam &

Since 1940, significant changes in the population of seabirds nesting on Manawagonish Island, New Brunswick have been observed. Most notably there were large increases in the numbers of nesting great black-backed gulls, Larus marinus, and double-crested cormora nts, Phalacrocorax JUfitus. Dispersal patterns for herring gulis, L. argenfatus, from this colony show a late summer and early fall movement northward in to the Northumberland Strait and Gulf of SI. Lawrence, as well as southward travel as far as the Gulf of Mexico and a summer concentration around Cape Cod. During the win ter months birds appear to congregate in metropolitan areas between long Island and Philadelphia.

Gray-hooded Gull, Chroicocephalus cirrocephalus (Vieillot, 1818), is distributed across South America and considered a resident, with individuals in their non-breeding period able to disperse over long distances. We report the first records of this species from the state of Espírito Santo, the only state on the Brazilian coast without previous records. We suggest that the geographical distribution of this species is expanding along the Brazilian coast, in accordance with what has been previously suggested for Gray-hooded Gull.

A ocupação das ilhas oceânicas sempre foi uma questão estratégica para os países com fronteira marítima. Desta forma, o Brasil mantém, desde 1950, o Posto Oceanográfico da Ilha da Trindade, o qual fornece infraestrutura básica para permanência humana na ilha, além de garantir a soberania nacional, a manutenção da Zona Econômica Exclusiva e o desenvolvimento continuado de pesquisas científicas. Em 2007 foi implantado o Programa de Pesquisas Científicas na Ilha da Trindade e a partir deste, com o incremento das pesquisas na ilha, foi construída uma Estação Científica para atender às necessidades de alojamento e ambiente de trabalho para os pesquisadores. A estação passou a ser objeto de monitoramento ambiental e um dos parâmetros avaliados foi o impacto da instalação da edificação – com o consequente aumento do número de pesquisadores –, em relação as aves marinhas. As atividades foram realizadas no período de 22/02 a 11/04/2013, utilizando três métodos de amostragens: contagem por po...

Despite the increase of literature on seabird plastic ingestion in recent years, few studies have assessed how plastic loads vary according to different sampling methods. Most studies use necropsies of seabirds with a natural cause of death, e.g. beached or predated, to determine plastic loads and monitor marine debris. Sampling naturally dead seabirds may be biased as they have perished because of their intrinsic factors, e.g. poor body condition, high parasite loads, sickness or predation, affecting estimates of plastic loads. However, seabirds killed accidentally may be more representative of the population. Here, we used the short-tailed shearwater Ardenna tenuirostris to test different sampling methods: naturally beached fledglings and accidentally road-killed fledglings after being attracted and grounded by artificial lights. We compared plastic load, body condition, and feeding strategies (through using feathers' δC and δN isotope niche) between beached and road-killed fl...

This study compares the δ15N values and the trophic position of two seabird species throughout the late Holocene in three regions in the southwestern Atlantic Ocean to assess the hypothesis that the decimation of megafauna led to changes in the trophic position of mesopredators. Modern and ancient mollusk shells were also analyzed to account for changes in the isotopic baseline through time. Results revealed that modern Magellanic penguins have higher δ15N values than their ancient conspecifics in the three regions, after controlling for changes in the isotopic baseline. This was also true for modern Imperial shags compared with ancient unidentified cormorants/shags from the two areas where ancient specimens were recovered (southern Patagonia and the Beagle Channel). Such temporal variability might be caused by three non–mutually exclusive processes: decreased availability of pelagic squat lobster resulting from decreasing primary productivity through the late Holocene, increased av...

A new species of giant petrel, Macronectes tinae sp. nov., is described from the Pliocene deposits of South Taranaki, New Zealand. The holotype is a near complete skull and the paratype a fragmentary left humerus; both come from the Tangahoe Formation, dating from the late Pliocene (Piacenzian or “Waipipian”; age estimated as ca. 3.36–3.06 Ma). The new species of giant petrel is the first fossil Macronectes ever reported. It is morphologically similar to the two present-day Macronectes spp., but it was a smaller bird. The skull is diagnosed by its overall smaller size, a proportionately longer apertura nasi ossea, and potentially by a shorter os supraocciptale. The humerus is diagnosed from both species by a proportionately less deep shaft, a more prominent medial portion of the epicondylus ventralis, and a larger and fusiform fossa medialis brachialis. The Tangahoe Formation is proving to be a remarkable source of marine vertebrate fossils and an important piece of the puzzle in un...

Among seabirds, lesser black-backed gulls (Larus fuscus) are considered to be at high risk of colliding with offshore wind turbines. In this respect, we used GPS tracking data of lesser black-backed gulls caught and tagged in two colonies along the Belgian North Sea coast (Ostend and Zeebrugge) to study spatial patterns in the species’ presence and behaviour in and around the Thornton Bank offshore wind farm (OWF). We found a significant decrease in the number of GPS fixes of flying birds from up to a distance of at least 2000 m towards the middle of the wind farm. Non-flying birds showed a similar avoidance of the wind farm interior, yet presence strongly peaked right at the wind farm’s edge, demonstrated to represent gulls perching on the outer turbine jacket foundations. The findings of this study reveal a strong within-wind farm variability in bird density, a most crucial parameter in collision risk modelling. The method presented here is straightforward and similar studies cond...