Meeting Abstract

P1.110  Friday, Jan. 4  Using multiple measures of individual condition to examine the impact of commercial bird food on wild birds. HUBBLE, CN*; WILCOXEN, TE; HORN, DJ; Millikin University; Millikin University; Millikin University chubble@millikin.edu

Many metrics have been used to assess the health of free-living vertebrates, with conflicting findings and differential support for these metrics. We examined the impact of bird feeding activities on individual condition in Central Illinois feeder-using species of birds. Specifically, we examined hematocrit, total plasma protein, fat deposition, and a body condition index that incorporates multiple structural measurements and mass to examine effects of commercial bird food on the condition of birds relative to birds at similar, nearby sites without feeders. In this 18-month study, we captured approximately 1200 birds of 11 species that are known to regularly use feeders. We found that feeders had a positive or neutral effect when it came to each of the measures and there was no evidence of a negative effect relative to control sites, at least in these measures of condition. There were also differences between the sexes and among species and our findings lend some support to certain measures of condition over others. Understanding differences in individual condition among songbirds and using multiple measures of condition allow us to understand the complex effects of an abundant and predictable food source in the natural habitat of birds.