PREY SELECTION BY URBAN-BREEDING MERLINS

Citation
Ns. Sodhi et Lw. Oliphant, PREY SELECTION BY URBAN-BREEDING MERLINS, The Auk, 110(4), 1993, pp. 727-735
Citations number
62
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Ornithology
Journal title
ISSN journal
0004-8038
Volume
110
Issue
4
Year of publication
1993
Pages
727 - 735
Database
ISI
SICI code
0004-8038(1993)110:4<727:PSBUM>2.0.ZU;2-1
Abstract
We identified 1,332 items belonging to 36 vertebrate species from prey remains collected near 65 Merlin (Falco columbarius) nests in Saskato on, Saskatchewan from May to July 1987-1990. Principal prey of breedin g Merlins was the House Sparrow (Passer domesticus). They along with t he Horned Lark (Eremophilia alpestris) were usually taken more frequen tly than expected from their relative abundance. Other potential prey species were usually taken in proportion to their relative abundance, or less often than expected. Proportions of adult House Sparrows in th e diet decreased while juveniles increased significantly as the Merlin breeding season progressed. During incubation and nestling phases, ma le and female House Sparrows were taken as expected. In the fledgling phase, Merlins took adult House Sparrows less often and juveniles more often than expected. The relative availability of different species p ositively correlated with that in the diet during the incubation and n estling phases. Merlins selected prey based on relative availability, independent of prey mass, but not independent of relative abundance. O ur data supported the prediction that increase in absolute abundance o f selected prey species increased the degree of prey selectivity.