Trophic interactions between brown and south polar skuas at Deception Island, Antarctica

It is broadly accepted that the brown skua (<i>Stercorarius antarcticus lonnbergi</i>) competitively excludes the south polar skua (<i>S. maccormicki</i>) from penguin colonies when breeding sympatrically, forcing the latter to feed on marine resources. The purpose of this wo...

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Detalles Bibliográficos
Autores principales: Graña Grilli, Maricel, Montalti, Diego
Formato: Articulo
Lenguaje:Inglés
Publicado: 2012
Materias:
Ciencias Naturales
Diet composition
Niche breadth
Niche overlap
South Shetland Islands
Stercorarius
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/146278
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-146278
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Naturales
Diet composition
Niche breadth
Niche overlap
South Shetland Islands
Stercorarius
spellingShingle Ciencias Naturales
Diet composition
Niche breadth
Niche overlap
South Shetland Islands
Stercorarius
Graña Grilli, Maricel
Montalti, Diego
Trophic interactions between brown and south polar skuas at Deception Island, Antarctica
topic_facet Ciencias Naturales
Diet composition
Niche breadth
Niche overlap
South Shetland Islands
Stercorarius
description It is broadly accepted that the brown skua (<i>Stercorarius antarcticus lonnbergi</i>) competitively excludes the south polar skua (<i>S. maccormicki</i>) from penguin colonies when breeding sympatrically, forcing the latter to feed on marine resources. The purpose of this work was to examine the diets and trophic niche breadths of each species where they co-occur and to determine the degree of overlap. To this end, we analyzed 169 pellets of brown skuas, collected in two different areas (20 individuals), and 152 of south polar skuas, collected in three different areas (18 individuals), on Deception Island, South Shetland Islands, Antarctica, during the austral summer 2000. Pellet analysis often underestimates the amount of easily digestible prey, but allows for comparisons of the relative contributions of different items in the diet. South polar skuas at our study locations consumed seven different food items and had a trophic niche breadth of 0.133 compared to brown skuas that fed on 10 different items and had a trophic niche breadth of 0.078. The niche overlap between the species was 82.1%. Penguins were the principal food source of both species, however, brown skuas fed mostly on chicks, while south polar skuas fed on adults (carcasses). The use of different age classes of penguins as a food source offers an alternative to competitive exclusion, allowing the coexistence of these species on Deception Island.
format Articulo
Articulo
author Graña Grilli, Maricel
Montalti, Diego
author_facet Graña Grilli, Maricel
Montalti, Diego
author_sort Graña Grilli, Maricel
title Trophic interactions between brown and south polar skuas at Deception Island, Antarctica
title_short Trophic interactions between brown and south polar skuas at Deception Island, Antarctica
title_full Trophic interactions between brown and south polar skuas at Deception Island, Antarctica
title_fullStr Trophic interactions between brown and south polar skuas at Deception Island, Antarctica
title_full_unstemmed Trophic interactions between brown and south polar skuas at Deception Island, Antarctica
title_sort trophic interactions between brown and south polar skuas at deception island, antarctica
publishDate 2012
url http://sedici.unlp.edu.ar/handle/10915/146278
work_keys_str_mv AT granagrillimaricel trophicinteractionsbetweenbrownandsouthpolarskuasatdeceptionislandantarctica
AT montaltidiego trophicinteractionsbetweenbrownandsouthpolarskuasatdeceptionislandantarctica
bdutipo_str Repositorios
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