Seabirds

The present work presents the first occurrence of seabirdsʼ fossils from pleistocenic fossiliferous deposits submerged along the inner continental shelf of Rio Grande do Sul state. The fossils presented here were collected during field works between 1999 and 2003 and consist of three cervical vertebrae and a partial left tibiotarsus. The fossilsʼ morphology and size are similar to those of a procellariiform seabird of the Thalassarche melanophrys Temminck 1828 species (black-browed mollymawk). The fossils are well-preserved, indicating that were not subject to significant re-working during transport from the source areas to the beach. This suggests that the submerged deposits are located near the present shoreline.

This paper reviews the occurrence and identification of orange-billed terns (genus Thalasseus) in eastern North America, with emphasis on molt, ageing, and the limits of identification among similar taxa: Lesser Crested Tern (T. bengalensis), Cayenne Tern (T. sandvicensis eurygnatha), and especially Elegant Tern (T. elegans), Elegant being the species named in most records of vagrant orange-billed terns considered herein. Also treated are possible drivers of population changes and of vagrancy, such as El Niño events in the Pacific.

Anthropogenic debris is rapidly spreading in marine environments and poses major problems to biodiversity and humans. However, mitigation strategies are limited by the lack of information on the accumulation patterns of these pollutants both at sea and in marine wildlife. Using observations from an uninhabited island in Delta du Saloum National Park, Senegal, we investigate here the prevalence and abundance of debris in nests of two sympatric seabird species, Caspian terns Hydroprogne caspia and great cormorants Phalacrocorax carbo, and its potential as an indicator of ocean pollution. We recorded debris in 15% of the Caspian terns' nests, and 40% of the great cormorants' nests. Plastics accounted for > 95% of items recorded in the nests of both species. Caspian terns collected a diverse array of debris, both in terms of types and colours, with a preference for hard plastics and white items. The great cormorants accumulated in nests mainly greenish fishing gears resembling the vegetation typically used as nest materials. Nests of both bird species contained soft plastic in proportions lower than those observed in the environment. Our results suggest that nests of Caspian terns and great cormorants are not useful indicators of pollution by anthropogenic debris in the surrounding waters of the Delta du Saloum National Park. Nests of great cormorants, however, have the potential to indicate areas vulnerable to plastic pollution associated to fishery. The high amount of debris in nests of this species demonstrates the need for a better implementation of waste management strategies in Senegal.

Most seabirds are diurnal foragers, but some species may also feed at night. In Peruvian pelicans (Pelecanus thagus), the
evidence for nocturnal foraging is sparse and anecdotal. We used GPS-dataloggers on five incubating Peruvian pelicans
from Isla Lobos de Tierra, Peru´ , to examine their nocturnality, foraging movements and activities patterns at sea. All
instrumented pelicans undertook nocturnal trips during a 5–7 day tracking period. Eighty-seven percent of these trips
(n = 13) were strictly nocturnal, whereas the remaining occurred during the day and night. Most birds departed from the
island after sunset and returned a few hours after sunrise. Birds traveled south of the island for single-day trips at a
maximum range of 82.8 km. Overall, 22% of the tracking period was spent at sea, whereas the remaining time was spent on
the island. In the intermediate section of the trip (between inbound and outbound commutes), birds spent 77% of the trip
time in floating bouts interspersed by short flying bouts, the former being on average three times longer than the latter.
Taken together, the high sinuosity of the bird’s tracks during floating bouts, the exclusively nocturnal trips of most
individuals, and the fact that all birds returned to the island within a few hours after sunrise suggest that pelicans were
actively feeding at night. The nocturnal foraging strategy of Peruvian pelicans may reduce food competition with the
sympatric and strictly diurnal Guanay cormorants (Phalacrocorax bougainvillii), Peruvian boobies (Sula variegata) and Bluefooted
boobies (S. nebouxii), which were present on the island in large numbers. Likewise, plankton bioluminescence might
be used by pelicans as indirect cues to locate anchovies during their upward migration at night. The foraging success of
pelicans at night may be enhanced by seizing prey close to the sea surface using a sit-and-wait strategy.

Townsend’s shearwater (Puffinus auricularis auricularis) is an endangered seabird endemic to the Revillagigedo Archipelago. It nested on Socorro, Clarion, and San Benedicto Islands. It was extirpated by the Barcena volcano on San Benedicto in 1952, and there are no recent indications of nesting. Introduced mammals—pigs and rabbits—preyed on them and destroyed habitat at Clarion; shearwaters were extirpated by 1988, and no breeding attempts have been reported since. Our results confirm that Socorro holds the last breeding grounds. We found breeding colonies above 800 m and a minimum population of 1100 individuals. This represents a significant reduction in distribution and population size. Intensive cat predation at Socorro could potentially kill ca. 350 females per season, and sheep progressively destroy nesting areas. Population projections suggest that demographic instability could occur in less than 100 years under severe predation and habitat degradation. Only low predation rates would allow population persistence for more than 150 years in spite of a declining population. Thus, the immediate eradication of all introduced mammals is necessary to prevent the extinction of this seabird.

Ecogeographical rules provide potential to describe how organisms are morphologically constrained to climatic conditions. Allen's rule (relatively shorter appendages in colder environments) remains largely unsupported and there remains much controversy whether reduced surface area of appendages provides energetic savings sufficient to make this morphological trend truly adaptive. By showing for the first time that Allen's rule holds for closely related endothermic species, we provide persuasive support of the adaptive significance of this trend for multiple species. Our results indicate that reduction of thermoregulatory cost during the coldest part of the breeding season is the most likely mechanism driving Allen's rule for these species. Because for 54% of seabird species examined, rise in seasonal maximum temperature over 100 years will exceed that for minimum temperatures, an evolutionary mismatch will arise between selection for limb length reduction and ability to accommodate heat stress.

Although the Eastern Tropical Pacific is well known for its diverse fauna, the seabirds occurring off Costa Rica's Pacific coast have received little scientific attention. With seabirds now the fastest declining avian group, a better understanding of seabird diversity and abundance in this region is urgently needed. We report on observations of Costa Rica's Pacific seabirds made during 19 days of observations on 11 offshore trips from 2006-2010. We provide, for the first time, spatially and seasonally explicit information on the distribution of 41 species of seabirds (nine families). Species diversity is higher during the dry-wet season (36 species) and wet-dry season transitions (36 species) than during the dry season (19 species). The fauna included three threatened species (Pterodroma phaeopygia, Procellaria parkinsoni, and Puffinus creatopus) and two near-threatened species (Psueudobulweria rostrata and Thalasseus elegans), highlighting the importance of Costa Rican waters for the conservation of seabirds. Rev. Biol. Trop. 64 (Suppl. 1): S235-S248. Epub 2016 February 01.

El ostrero americano Haematopus palliatus pitanay se distribuye en la costa oeste de América del Sur, desde el sur de Colombia hasta el centro de Chile. Las referencias sobre la biología reproductiva y áreas de
anidamiento de esta subespecie son escasas. Entre marzo de 2012 y julio de 2015 se realizaron evaluaciones en seis playas arenosas en el Perú, obteniendo registros sobre la reproducción de la especie en Uripe (La Libertad, 08°14’S-78°58’O), Punta Negra (Lima, 12°22’S-76°47’O), Puerto Viejo (Lima, 12°34’S-76°42’O), Asia (Lima, 12°45’S-76°37’O) y Cerro Azul (Lima, 13°01’S-76°28’O). En Lima, la puesta se realizó entre abril y julio, encontrándose un promedio de 2,5 huevos por nido (rango = 1-4). La mayor parte de los nidos (62,50%), y polluelos y volantones (83,33%) fueron observados dentro de las playas privadas cerradas; lo que parece ser una respuesta de la subespecie al disturbio causado por las actividades recreativas en las playas públicas.
Adicionalmente, se obtuvieron otros registros basados en observaciones casuales por los autores, entrevistas y revisión bibliográfica, identificando un total de 14 áreas reproductivas en el Perú (07°S-17°S), en donde la puesta se registró durante todos los meses del año, con una tendencia progresiva de la fecha de inicio de la reproducción con un aumento en la latitud.

""Marine top predators play a pivotal role in stabilizing marine food webs. Their presence is also a good bio-indicator of the state of our oceans making them invaluable tools for detecting changes in the marine environment. However, it is important to grasp a fundamental understanding of how predators integrate with their environment if we are to fully understand the link between top predators and lower trophic levels. Seabirds are top predators facing substantial threats from fisheries and climate change, thus understanding their ecology is of growing importance. Their life histories such as long life spans and late maturation have evolved as a means to cope with the heterogeneous ocean landscape and scarce prey availability. These birds have also evolved a suite of strategies to increase the probability of locating these scarce and patchy prey distributions. For instance, many seabirds, especially long ranged birds such as albatrosses and larger penguins, are hypothesized to utilize temperature gradients to locate meso-scale (100-1000 km) ocean physical features such as eddies, fronts and upwelling zones where nutrients are advected to the euphotic zone from deeper cool bottom waters. This nutrient injection drives productivity in the ocean making these features ideal feeding grounds for top predators. Seabirds are also capable of using olfactory cues and currents to locate these features. However on a fine to coarse scale (1-100 km) it is less understood how these predators locate patchy prey distributions where cues such as temperature may be ephemeral.

African Penguins have short foraging ranges (10-50 km), and forage in dynamic coastal environments making them an ideal model for understanding how short-ranged top predators locate their prey. By modeling the sea-surface thermal habitat preferences, and the dive behavior in relation to thermoclines of African Penguins I assess how these short-ranged birds use ocean physical processes to increase the probability of locating their small pelagic prey. African Penguins breeding on Bird Island, Algoa Bay, were capable of utilizing temperature as a potential cue to foraging in three-dimensions. Penguins commuted east and south of their colony likely predicting the occurrence of cool nutrient rich waters from a periodic upwelling cell. Penguins departed in the early morning travelling towards these areas, maximizing the time they foraged during the day in cooler waters with a higher probability of containing prey patches. Penguins used a correlated random search strategy during foraging suggesting that these birds were continuously searching for prey, and it is therefore likely that penguins are limited by the patchy distribution of prey rather than a heterogeneous marine environment. When diving, penguins’ utilized thermoclines as either a potential cue to prey or by association, as their prey may be scattered around thermoclines. Penguins dived deeper foraging below the thermocline when the thermocline depth increased and also responded in their dive behaviour under different thermocline structures. For instance, when thermoclines were a diffuse barrier to nutrients and less likely to concentrate prey, birds dived deeper towards the benthos. Warm water intrusions into the bay from the Agulhas Current resulted in birds diving deeper in search of cooler bottom waters.

This research also demonstrates the dual utility of bio-loggers as a method for generating accurate, high-resolution oceanographic data. These data can be used in future studies, generating a cross disciplinary platform for research. This thesis augments our knowledge base of the African Penguin. African Penguins show flexibility in their foraging behaviour by adjusting their dive behaviour to subsurface thermal structures. Penguins also demonstrated foraging optimization by using temperature cues and behavioral switching to maximize the probability of locating prey patches on a fine temporal and spatial scale.  ""

The ecology and life history of marine megafauna can answer the ecological importance of a region. This study assesses and monitors the abundance and home range of sea turtles, seabirds, marine mammals and the association with coastal microhabitats in potentially impacted areas at the Rio Doce river mouth, Comboios, and Piraquê-açu river mouth after the collapse of the Fundão dam. Remotely Operated Vehicles (ROV) and UAVs (Unmanned Aerial Vehicles, or drones) were used for megafauna species identi fication, behavior, population data, habitat characterization, and monitoring of environmental protection areas. The species Sotalia guianensis and
Pontoporia blainvillei were the most recorded cetaceans, and the main observed behavior was feeding. Guiana dolphin (S. guianensis) occurs in greater density in the Rio Doce river mouth region, resulting in more than 10 sightings/km2, while franciscana (P. blainvillei) were the most concentrated Comboios area. The seabirds (all species) had up to 15 sightings/km2 at the Rio Doce river mouth, the highest density among sampled areas. The green turtle (Chelonia mydas) was the most frequently recorded, followed by the leatherback turtle (Dermochelys coriacea). The green turtle occurred at a higher concentration at the Piraquê-Açu river mouth (above 6 sightings/km2). The sites closest to Rio Doce river mouth and Comboios predominantly showed mud bottoms, while those at Piraquê-Açu mouth were mostly reef structures. The estuarine areas showed greater importance for megafauna than marine areas.

Climate-induced glacier retreat is considered in the context of its reducing the sea-ice contact zone used by marine birds and mammals as important foraging grounds and may cause declines in their numbers. To test this hypothesis, a survey was conducted in diversified habitats of a rapidly deglaciating Arctic fjord in Svalbard. Of the fifteen seabird and four mammal species found, coastal surface-feeders prevailed over benthic-feeders and pelagic pursuit-divers. Deep tidewater glacier bays were used by the most numerous but least heterogeneous foraging community, in contrast to the shallow lagoons of coastline-terminating glaciers and deglaciated shorelines. After the 15 years of glaciers retreat documented in Hornsund, the sea-ice contact zone used by birds and mammals has not declined. On the contrary, the increasing freshwater supply from underwater glacial rivers raising zooplank-ton up to the surface, thus making it available to seabirds, enhances the attractiveness of tidewater glacier bays. Along with the stage of retreat, the importance of glacier bays as feeding grounds changes. Foraging conditions deteriorate when the glacier terminus reaches the coastline and the glacier bay becomes shallower. However, glacier retreat enlarges the area of littoral habitats accessible to benthophages. Glacier-related habitats situated close to colony are used as alternative/emergency feeding grounds by seabirds that normally forage outside the Climatic Change

Land-breeding marine animals such as penguins, flying seabirds and pinnipeds are important components of marine ecosystems, and their abundance has been used extensively as an indication of ecosystem status and change. Until recently, many efforts to measure and monitor abundance of these species’ groups have focussed on smaller populations and spatial scales, and efforts to account for perception bias and availability bias have been variable and often ad hoc. We describe a suite of new methods, technologies and estimation procedures for costeffective, large-scale abundance estimation within a general estimation framework and illustrate their application on large Ade´lie penguin populations in two regions of East Antarctica. The methods include photographic sample counts, automated cameras for collecting availability data, and bootstrap estimation to adjust counts for the sampling fraction, perception bias, and availability bias, and are
applicable for a range of land-breeding marine species. The
methods will improve our ability to obtain population data
over large spatial and population scales within tight logistic, environmental and time constraints. This first application of the methods has given new insights into the biases and uncertainties in abundance estimation for penguins and other land-breeding marine species. We provide guidelines for applying the methods in future surveys.

A knowledge of the foraging strategies of marine predators is essential to understand the intrinsic factors controlling their distribution, abundance and their ecological function within the marine ecosystem. Here, we investigated for the first time the foraging movements and activity patterns of Audouin’s gull Larus audouinii by using satellite-tracking data from eight breeding adults in the main colony of the species worldwide (Ebro Delta, NW Mediterranean). Tagged gulls foraged in the marine area close to the breeding colony (62% of foraging locations) and in the terrestrial area of the Ebro Delta (mainly rice fields; 38% of foraging locations). The foraging activity patterns changed significantly throughout the day; lower from dusk through the first half of the night (19-1 h; 32% of active locations) and higher during the rest of the day (1–19 h; 75.5 ± 4.3% of active locations). These results confirm the foraging plasticity of this seabird and, based on previous information about the dietary habits of this species, we hypothesize how its time-dependent activity patterns and habitat use could be associated with variations in the availability of marine food resources (e.g. diel vertical migrations of pelagic fish) and the exploitation of terrestrial resources (e.g. American crayfish Procambarus clarkii).

Breeding success of seabirds critically depends on their foraging success offshore. However, studies combining at-sea tracking and visual provisioning observations are scarce, especially for smaller species of seabirds. This study is the first in which breeding Sandwich Terns were tracked with GPS-loggers to collect detailed data on foraging habitat use in four breeding seasons. The maximum home range of individual Sandwich Terns comprised approximately 1900 km 2 and the average foraging range was 27 km. Trip durations were on average 135 min with average trip lengths of 67 km. Actual foraging behaviour comprised 35% of the time budget of a foraging trip. Substantial year-to-year variation was found in habitat use and trip variables, yet with the exception of 2012, home range size remained similar between years. Food availability, chick age and environmental conditions are proposed as the main driving factors between inter-and intra-annual variations in trip variables. Our multi-method approach also provided geo-referenced information on prey presence and we conclude that future combining of colony observations and GPS-loggers deployments can potentially provide a near complete insight into the feeding ecology of breeding Sandwich Terns, including the behaviour of birds at sea.

ABStRACt: Distribution, abundance and seasonality of Laughing Gulls, Leucophaeus atricilla (Charadriiformes: Laridae) in Brazil. Here, we present a review of existing information along with newly collected data on the distribution, abundance and seasonality of Laughing Gulls, Leucophaeus atricilla, in Brazil. This work combines a literature survey, examination of museum specimens and recent fieldwork. Based on survey data carried out along the coast of northern Brazil (in the State of Pará), as well as data taken from the literature, we estimate that every year, approximately 30,000 Laughing Gulls spend the non‑breeding season (August‑March) along northern coast of Brazil, in the States of Amapá, Pará and Maranhão. In addition, we present 12 new records of this species from areas where it does not frequently occur; these new locations are widely distributed and include the interior of the State of Amazonas, and from the States of Ceará, Rio de Janeiro and São Paulo. Observations of Laughing Gulls from the same localities in southeast Brazil over several years may suggest that the species is expanding its non‑breeding distribution. RESuMo: Neste trabalho são apresentadas novas informações, obtidas pelos autores e/ou colaboradores, sobre ocorrência, abundância e sazonalidae de Leucophaeus atricilla no Brasil, bem como uma revisão dos dados sobre essa espécie, disponíveis na literatura e em coleções de museus. Baseado em resultados de contagens e dados da literatura, estima‑se que, anualmente, perto de 30.000 indivíduos de L. atricilla passem o período não‑reprodutivo (agosto‑março) na costa brasileira, principalmente nos estados do Amapá, Pará e Maranhão. Em adição, são apresentados 12 novos locais de ocorrência para essa espécie nas regiões norte (Amazonas), nordeste (Ceará) e sudeste (Rio de Janeiro e São Paulo) do país. Registros no sudeste, num mesmo local e em diferentes anos, representam as primeiras informações sobre L. atricilla na região, sugerindo, ainda, que a espécie está ampliando sua distribuição geográfica na área não‑reprodutiva.