1. The number of great skuas Catharacta skua Brünnich breeding at St Kilda, Outer Hebrides, has increased rapidly in recent years, making it currently the second largest colony outside Shetland and the fastest growing in the UK. In comparison with Shetland, where the diet consists mostly of sandeel Ammodytes marinus Raitt and discarded gadoid fish, and very rarely of birds, great skuas at St Kilda feed far more extensively upon seabirds. This paper incorporates metabolic, dietary and demographic data to estimate the total mass of different prey consumed at St Kilda and to assess the potential impact of this predation on other seabird populations. 2. On the basis of a bioenergetics model incorporating fundamental life‐history parameters, the great skua population at St Kilda was estimated to require 141 × 106 kJ of energy per season, most of which (88·0%) was necessary for the maintenance and activity of breeding adults. Energy demand was considerably lower for non‐breeders (2·5% of the total), and for chicks and fledglings (9·2%). 3. In addition to seabirds, great skua diet at St Kilda also included a considerable proportion of fish and goose barnacles Lepas sp. However, because of differences in mean meal mass and caloric density, meals of larger seabird prey were more important in terms of their energetic contribution in the diet than in terms of their relative abundance. 4. Combining the bioenergetics and prey consumption models, it was estimated that a total mass of 12·2 tonnes of fish, 1·6 tonnes of goose barnacles and 8·8 tonnes of seabirds was consumed by the great skua population at St Kilda to fulfil its total energy requirement in 1996. Overall seabird consumption was estimated to be 40,800 seabirds of seven different species. Although a proportion of birds killed are likely to be visiting non‐breeders, the magnitude of this figure nonetheless suggests that great skuas may have a considerable impact on the internationally important populations of some seabirds at St Kilda.
Journal of Applied Ecology – Wiley
Published: Apr 1, 1999
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera