Keywords
multispecies feeding flocks
penguins
Puerto Deseado
seabirds
terns
Abstract
The objective of this work was to study the multispecies feeding flocks of marine birds in the Firth of Deseado, Santa Cruz. During one year, we observed specific composition, species abundance and duration of the assemblages. A total of 91 associations were recorded during the fall, spring and summer, being absent in winter, when fishes that form schools are far away from the coast and not come into the firth. The most frequent size was 100 individuals and they were formed, on average, by three species. Their average duration (± SD) was 28.8 ± 15.8 min. We identified 12 species of birds and the Commerson´s dolphin (Cephalorhynchus commersonii) in the flocks. The most abundant and frequent species were terns (Sterna hirundinacea and Thalasseus sandvicensis), Kelp Gull (Larus dominicanus) and Magellanic Penguin (Spheniscus magellanicus). The Rock Shag (Phalacrocorax magellanicus) was the least frequent one among the species that breed in the firth and which formed part of the associations. Magellanic Penguins and terns were positively associated. In the breeding season, Kelp Gulls and terns were found together. In the Firth of Deseado, studied associations were Type I, in which the penguins would be carrying out an important role in their formation. Since they are divers, they could take their prey to the surface that remains then more available for terns and gulls. These birds feed on the surface and in a conspicuous way, so they would be acting like catalysts species.
References
AU D Y PITMAN R (1986) Seabird interactions withdolphins and tuna in the eastern tropical Pacific.Condor 88:304–317
BOSWALL J Y MACIVER D (1975) The Magellanic Pen-guin Spheniscus magellanicus. Pp. 271–306 en:STONEHOUSE B (ed) The biology of penguins. MacMillenPress, Londres
CAMPHUYSEN CJ Y WEBB A (1999) Multi-species feedingassociations in North Sea seabirds: jointly exploit-ing a patchy environment. Ardea 87:177–198
CHILTON G Y SEALY SG (1987) Species roles in mixed-species feeding flocks of seabirds. Journal of FieldOrnithology 58:456–463
COUSSEAU MB Y PERROTTA RG (1998) Peces marinos deArgentina: biología, distribución, pesca. INIDEP, Mardel Plata
FRERE E Y GANDINI PA (2001) Aspects of the breedingbiology of the red-legged cormorant Phalacrocoraxgaimardi on the Atlantic coast of South America.Marine Ornithology 29:67–70
FRERE E, QUINTANA F Y GANDINI PA (2002) Divingbehaviour of the red-legged cormorant in south-eastern patagonia, Argentina. Condor 104:440–444
GANDINI PA Y FRERE E (1995) Distribución, abundanciay ciclo reproductivo del cormorán gris Phalacrocoraxgaimardi en la costa patagónica, Argentina. Hornero14:57–60
GANDINI PA Y FRERE E (1998) Seabirds and shorebirdsdiversity and associated conservation problems inPuerto Deseado, Patagonia, Argentina. OrnitologiaNeotropical 9:13–22
HARRISON NM, WHITEHOUSE MJ, HEINEMANN D,PRINCE PA, HUNT GL JRY VEIT RR (1991) Observa-tions of multispecies seabirds flocks around SouthGeorgia. Auk 108:801–810
HOFFMAN W, HEINEMANN D Y WIENS JA (1981) The ecol-ogy of seabirds feeding flocks in Alaska. Auk98:437–456
JEHL JR JR (1974) The distribution and ecology ofmarine birds over the continental shelf of Argen-tina in winter. Transactions of the San Diego Society ofNatural History 17:217–234
MAHON TE (1992) The role of Marbled Murrelets inmixed-species feeding flocks in British Columbia.Wilson Bulletin 104:738–743
MALACALZA VE, BERTELLOTTI NM Y PORETTI TI (1997)Variación estacional de la dieta de Phalacrocoraxmagellanicus (Aves: Phalacrocoracidae) en PuntaLoma (Chubut, Argentina). Neotropica 43:35–37
MILLS KL (1998) Multispecies seabird feeding flocksin the Galápagos Islands. Condor 100:277–285
OSTRAND WD (1999) Marbled murrelets as initiatorsof feeding flocks in Prince William Sound, Alaska.Waterbirds 22:314–318
SAFINA C Y BURGER J (1988) Ecological dynamicsamong prey fish, bluefish and foraging commonterns in an Atlantic coastal system. Pp. 95–173 en:BURGER J (ed) Seabirds and other marine vertebrates.Columbia University Press, New York
SANCHEZ RP, REMESLO A, MADIROLAS A Y CIECHOMSKIJDZ (1995) Distribution and abundance of post-lar-vae and juveniles of the Patagonian sprat, Sprattusfuegensis and related hydrographical conditions.Fisheries Research 23:47–81
SEALY SG (1973) Interespecific feeding assemblagesof marine birds off British Columbia. Auk 90:796–802
SIEGEL S Y CASTELLAN NJ JR (1988) Nonparametric sta-tistics for the behavioral sciences. Segunda edición.McGraw Hill International, Singapore.
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.