The Effects of Ectoparasites on Tree Swallow Biology

Ectoparasites live on their hosts and have the potential to affect an individual\u27s survival and reproductive success. We examined the effects of ectoparasites on the biology of Tree Swallows nesting at GVSU from 1993-2010. We estimated louse loads by counting the number of holes chewed by lice in the feathers of each wing and the tail. We compared the number of holes found in four groups of breeding swallows: first-year females, after-hatching year females, after-second year females, and males. There was no significant difference in the number of holes of birds examined early in the season and those studied late in the season. First-year and after-hatching year females had significantly more holes than did after-second year females. After-second year females also had significantly fewer holes than did males. Swallows with more breeding experience had fewer louse holes. The number of holes may indicate the quality of individual swallows