Do migrants influence the foraging behaviour of the insectivorous Cyprus Wheatear, Oenanthe cypriaca, at a stopover site? (Aves: Passeriformes)

Abstract

During their staging at stopover sites, migrants may compete with resident species over food resources (“resource competition hypothesis”), or migrants feed on surplus that is not utilised by the residents. Here, I studied foraging behaviour of the Cyprus Wheatear, Oenanthe cypriaca, a ubiquitous and common species with a broad niche range, on Cyprus, which is an important stopover site during intercontinental spring migration. During adverse weather conditions, perch height and aerial sallying were lower and perch/pounce activity was higher. Average perch height and sallying increased over the season, while perch-pounce foraging decreased. There was no influence of clock time. Bivariate correlations suggested an influence of migrants on perch height but not on other variables. Using a series of regression analyses with sex, time of day, date, weather conditions and number of migrants as independent variables revealed no influence of the number of migrants on the foraging behaviour of the Cyprus Wheatear. This suggests that the abundance of migrants does not lead to a change in the behaviour of the Cyprus Wheatear.

Keywords:

• Resource competition
• bird migration
• foraging behaviour
• stopover sites
• Oenanthe cypriaca

Acknowledgments

I am grateful to Dr. Volker Dierschke for helpful comments on the manuscript.