Abstract

The presence of one of the largest colonies of House Martins in Europe on the small island of Stora Karlso, Sweden, led us to investigate the source of their food by analysis of stable isotopes of carbon and nitrogen. Carbon isotopic values of House Martin nestlings were the same as those of Common Guillemot Uria aalge nestlings fed on marine fish, but differed from local Collared Flycatcher Ficedula albicollis nestlings fed on woodland insects. We infer that these House Martins fed their chicks almost exclusively on insects that had used nutrients derived from seabirds, indicating a dependence on the presence of a large seabird colony. We suggest by extension that some populations of island passerines of high conservation importance may also be dependent on nutrient subsidies from seabird colonies.

Keywords

Common Guillemot; food webs; passerines; stable isotope analysis

Published in

Ibis
2014, Volume: 156, number: 3, pages: 676-681

UKÄ Subject classification

Ecology
Zoology


Publication identifier

DOI: https://doi.org/10.1111/ibi.12150

Permanent link to this page (URI)

https://res.slu.se/id/publ/84200