Titre du document / Document title
Temporal patterns in the diet and food partitioning in imperial cormorants (Phalacrocorax atriceps) and rock shags (P. magellanicus) breeding at Bahía Bustamante, Argentina
Auteur(s) / Author(s)
PUNTA Gabriel (1) ;
YORIO Pablo (2) ;
HERRERA Gonzalo (1) ;
Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)
(1) Dirección General de Intereses Marítimos y Pesca Continental, 9 de Julio y J. A. Roca, 9103, Rawson, Chubut, ARGENTINE
(2) Centro Nacional Patagónico (CONICET) and Wildlife Conservation Society, Boulevard Brown s/n, 9120, Puerto Madryn, Chubut, ARGENTINE
Résumé / Abstract
We studied the diet of Imperial Cormorants (Phalacrocorax atriceps) and Rock Shags (P. magellanicus) at Bahía Bustamante, Argentina, between 1992 and 1994. We analyzed pellet casts (1887 from Imperial Cormorants and 799 from Rock Shags) and regurgitations of stomach contents (260 from Imperial Cormorants and 24 from Rock Shags). Imperial Cormorants and Rock Shags fed on at least 22 and 21 different types of prey, respectively. The main prey species during all study years were fish: Engraulis anchoita for Imperial Cormorants and Patagonothen sp. for Rock Shags. For both species, the consumption of the main food categories as estimated by pellet analysis was similar among years. A significant relationship was found between Imperial Cormorant and Rock Shag diets during the three years, while the diet overlap index was relatively high. During all years, Imperial Cormorants consumed a significantly larger proportion of pelagic or demersal fish than did Rock Shags, while Rock Shags consumed benthic fish in a greater proportion than did Imperial Cormorants. Mean maximum diving depth, determined using capillary tube depth gauges, of Imperial Cormorants (24.4 m ± 18.8 SD) was significantly greater but more variable than that of Rock Shags (9.3 m ± 4.1 SD).
Revue / Journal Title
The Wilson bulletin
ISSN
0043-5643
CODEN WILBAI
Source / Source
2003, vol. 115, n
o3, pp. 307-315 [9 page(s) (article)] (1 p.1/4)
Langue / Language
Anglais
Editeur / Publisher
Wilson Ornithological Society, Lawrence, KS, ETATS-UNIS
(1894)
(Revue)
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Localisation / Location
INIST-CNRS, Cote INIST : 5181, 35400011714491.0130
Nº notice refdoc (ud4) : 15675130
