Morphological variation in biological structures may be driven by genetic and environmental factors, such as inter- and intraspecific competition for resources. In seabirds, although the bill is also involved in vocalization, olfaction, sexual selection and defence, the main drivers of high morphological plasticity in bill size and shape appear to relate primarily to diet and thus to niche differentiation. Here, we combined geometric morphometrics and comparisons of linear measurements as a precise tool for measuring shape variation in anatomical features, to investigate the differences among species and populations (island groups) in bill shape of three planktivorous petrels (Antarctic prion Pachyptila desolata, blue petrel Halobaena caerulea and thin-billed prion Pachyptila belcheri). Fieldwork was carried out in South Georgia (54° 0′ S, 38° 3′ W), Falkland (51° 42′ S, 57° 51′ W), Diego Ramírez (56° 31′ S, 68° 44′ W) and Kerguelen (49° 20′ S, 69° 20′ E) Islands, from 2010 to 2021. Results show that the bills of Antarctic prions were more robust and shorter, appropriate for filtering large amounts of small prey. Blue petrels and thin-billed prions had narrower and longer bills, effective for catching and tearing large single prey. Also, Antarctic prions and blue petrels from Kerguelen had longer and narrower bills than conspecifics from other colonies, which could potentially be explained by geographic variation in diet. In conclusion, prey availability and diversity appear to be important factors influencing variation in bill morphology. This study highlights the utility of geometric morphometrics for investigating bill shape variation in seabirds. Nevertheless, further studies are needed to better understand selective pressures leading to morphological variation of biological structures.

The Chilean coast holds a high seabird diversity and also extensive fisheries that interact with birds producing bycatch. We used data on beached seabirds reported by news media to depict spatial and temporal patterns of fishery-related seabird mortality and correlated these data with the spatial and temporal fishing effort of the three main purse-seine fleets operating in south-central Chile (33 to 40 degrees S). Between 2005 and 2019 we detected 97 mortality events reporting >19,000 beached seabirds attributed to bycatch. Mortality was recorded between 18 and 53 degrees S (similar to 3800 km of coastline), affecting 16 seabird species, with 90% concentrated between 33 and 40 degrees S (800 km), exactly where purse-seine fleets operate. Sooty shearwater (Ardenna grisea) comprised 70% of all dead birds recorded. Magellanic penguins (Spheniscus magellanicus) and guanay cormorants (Phalacrocorax boungainvillii) were also affected. Mortality events of Sooty shearwaters was highest (P < 0.001) between February and May (54%) and October-November (36%), coinciding with the timing of the species migratory movements; shearwater mortality was particularly high at 36-37 degrees S (50%) and 39-40 degrees S (36%). Sooty shearwater mortality presented a very high spatial overlap (93%) and significant temporal correlation (0.64) with combined industrial and artisanal purse-seine fishing effort targeting on Peruvian anchovy (Engraulis ringens) and Araucanian herring (Strangomera bentincki). Our study shows when and where seabirds are more susceptible to mortality due to interactions with fisheries along the Chilean coast. This information could be used by authorities to regulate the fishing activity and focus conservation efforts to the most affected species at the appropriate spatial and temporal scales.

ABSTRACT The Kelp Gull (Larus dominicanus) is a widespread and abundant seabird species inhabiting much of the southern hemisphere, where at least 6 subspecies are recognized. For the nominate subspecies L. d. dominicanus present in South America, limited information is available on its basic life history traits. In this note we present information on longevity and philopatry based on the resighting of 3 Kelp Gull individuals banded as chicks at their natal colony in central Chile. All birds returned to breed at their natal island and established their nests within 50–80 m of their natal subcolony. Maximum observed longevity ranged between 17.5 and 22.1 years. We consider this information on life history and behavior valuable for management purposes as this subspecies is rapidly increasing at some coastal regions of South America and it may become a problematic species to humans and other seabird populations.

El piuchén (Desmodus rotundus, E. Geoffroy Saint Hillaire, 1810) es la única especie de quiróptero hematófago presente en el territorio chileno. Su distribución está descrita desde el norte de México hasta las zonas costeras de la Región de Valparaíso (zona del matorral costero). El presente estudio reporta la observación de al menos 20 individuos en una nueva localidad, la que amplía el límite latitudinal sur en territorio chileno hasta la Comuna de Navidad, Región del Libertador Bernardo O´Higgins. Específicamente en el islote Pupuya, ubicado frente a la Vega de Pupuya.

Aggression between chicks and fledglings, at times ending in siblicide and cannibalism, has been mostly studied among nest mates. It is frequent among colonial-nesting birds and is usually related to competition for limiting resources (e.g., food and space) and competitive disparities between siblings, among other factors. We report three observations of fully-grown Peruvian Pelican (Pelecanus Magus) fledglings attacking unrelated conspecific nestlings at a breeding colony in central Chile. One case ended in cannibalism. Five elements were common in all three cases: (1) nestlings that were attacked were left unattended by their parents in the nest, (2) nestlings that were attacked were newly hatched (up to 5 days of age), (3) aggressors were fully-grown fledglings (60-75 days of age), (4) aggressive fledglings always attacked nestlings in groups, and (5) all cases were observed late in the breeding season. We suggest aggression toward and cannibalism of nestlings by fledglings are opportunistic behaviors, based on the opportunity of finding unattended nests and are triggered by food deprivation, although hormonal mechanisms may also be involved. Our observations constitute the first report of aggression and cannibalism by Peruvian Pelican fledglings. Received 20 January 2012. Accepted 18 April 2012.