MEPS 452:269-285 (2012)  -  DOI: https://doi.org/10.3354/meps09670

Feeding ecology and movements of the Barolo shearwater Puffinus baroli baroli in the Azores, NE Atlantic

Verónica C. Neves1,*, Joël Bried1, Jacob González-Solís2, Jose L. Roscales2,3, Malcolm R. Clarke4

1Departamento de Oceanografia e Pescas, Centro do IMAR da Universidade dos Açores, Rua Frederico Machado n°4,
9901-862 Horta, Faial, Azores, Portugal
2Institut de Recerca de la Biodiversitat (IRBio) and Departament de Biologia Animal, Universitat de Barcelona, Avenida Diagonal 645, 08028 Barcelona, Spain
3Departamento de Análisis Instrumental y Química Ambiental, Instituto de Química Orgánica general (IQOG-CSIC), Calle Juan de la Cierva 3, 28006 Madrid, Spain
4Rua do Porto 18, 9930-430 Lajes do Pico, Azores, Portugal

ABSTRACT: Trophic ecology and movements are critical issues for understanding the role of marine predators in food webs and for facing the challenges of their conservation. Seabird foraging ecology has been increasingly studied, but small elusive species, such as those forming the ‘little shearwater’ complex, remain poorly known. We present the first study on the movements and feeding ecology of the Barolo shearwater Puffinus baroli baroli in a colony from the Azores archipelago (NE Atlantic), combining global location-sensing units, stable isotope analyses of feathers (δ13C and δ15N), stomach flushings and data from maximum depth gauges. During the chick-rearing period, parents visited their nests most nights, foraged mainly south of the colony and fed at lower trophic levels than during the non-breeding period. Squid was the most diverse prey (6 families and at least 10 different taxa), but species composition varied considerably between years. Two squid families, Onychoteuthidae and Argonautidae, and the fish family Phycidae accounted for 82.3% of ingested prey by number. On average, maximum dive depths per foraging trip reached 14.8 m (range: 7.9 to 23.1 m). After the breeding period, birds dispersed offshore in all directions and up to 2500 km from the breeding colony, and fed at higher trophic levels. Overall, our results indicate that the Barolo shearwater is a non-migratory shearwater feeding at the lowest trophic level among Macaronesian seabirds, showing both diurnal and nocturnal activity and feeding deeper in the water column, principally on small schooling squid and fish. These traits contrast with those of 3 other Azorean Procellariiformes (Cory’s shearwater Calonectris diomedea, the Madeiran storm-petrel Oceanodroma castro and Monteiro’s storm-petrel O. monteiroi), indicating ecological segregation within the Azorean seabird community.


KEY WORDS: Barolo shearwater · Puffinus baroli baroli · Diet · Foraging behaviour · Stable isotopes · Activity patterns · At-sea distribution · North-eastern Atlantic


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Cite this article as: Neves VC, Bried J, González-Solís J, Roscales JL, Clarke MR (2012) Feeding ecology and movements of the Barolo shearwater Puffinus baroli baroli in the Azores, NE Atlantic. Mar Ecol Prog Ser 452:269-285. https://doi.org/10.3354/meps09670

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