Demographic Patterns of Feather Damage from Chewing Lice in Tree Swallows

We examined patterns of feather damage caused by chewing lice in Tree Swallows. We counted the number of louse-chewed holes in the feathers of swallows nesting in west Michigan from 1993-2010 and compared the number of holes found in the feathers of breeding second-year (SY) females, after-hatching year (AHY) females, after-second year (ASY) females, and males. ASY-females had significantly fewer holes than any other breeders. For swallows that returned to breed more than three times, the number of holes was consistent. SY- and AHY-females and their mates did not significantly differ in the number of holes. ASY-females had significantly fewer holes than did their mates. For returning breeders, there were no significant correlations between the number of holes and morphology. In contrast, hole number was negatively correlated with mass and right wing length in males. Collectively, these data suggest little association between damage to feathers by chewing lice and Tree Swallow fitness