Open AccessThe diet of black guillemots Cepphus grylle in Shetland
Author(s) -
Ewins P. J.
Publication year - 1990
Publication title -
ecography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.973
H-Index - 128
eISSN - 1600-0587
pISSN - 0906-7590
DOI - 10.1111/j.1600-0587.1990.tb00593.x
Subject(s) - shetland , biology , fauna , invertebrate , benthic zone , fish <actinopterygii> , fishery , morning , zooplankton , ecology , zoology , geography , forestry , botany
The diet of black guillemots Cepphus grylle (L.) was studied in Shetland between 1982 and 1985, both during and outside the breeding season. Full‐grown birds consumed a wide variety of fish and invertebrate species in summer, broadly reflecting the diversity of the inshore benthic fauna. In winter a greater diversity of invertebrates was taken, which assumed increased importance in the diet as the availability of benthic fish probably declined. Chicks were fed a diet of fish, with 70–80% being sandeels Ammodytes marinus and butterfish Pholis gunnellus on the island of Mousa. Sandeels were delivered more frequently in the early morning, coincident with a peak in their feeding activity. Older chicks were fed significantly longer fish. The composition of chick diet varied significantly with date, not chick age. A seasonal decline in the proportion of sandeels in the chick diet may have reflected changes in Zooplankton abundance, but the possibility that intensive industrial fishing of sandeels had adversely affected local stocks can not be ruled out.