SHORT COMMUNICATION Coccidial infection does not influence preening behavior in American goldfinches

Abstract Preening behavior in birds is important for the main-tenance of thermoregulatory and ornamental functions of plum-age. It has been repeatedly demonstrated that birds trade off time between plumage maintenance and other activities. However, the condition-dependent constraints of preening re-main virtually unstudied. Here, we present the first experimen-tal test of the hypothesis that intestinal parasite infection impairs preening activity. We studied male American goldfinches (Spinus tristis), a species with carotenoid-based plumage col-oration. Following pre-alternate (spring) molt, we manipulated the health of males by infecting some birds with Isospora spp. coccidia and keeping others free of the infection. Although the goldfinches increased preening throughout the captive period, we found no significant effect of coccidial treatment on preening behavior. The effect of coccidia on plumage mainte-nancemay bemore pronounced under natural conditions where birds have limited access to food and engage in more activities that might limit time available for preening