Meeting Abstract

P2.97  Jan. 5  Reproductive status and hematozoan parasite load in the opportunistically breeding and nomadic red crossbill, Loxia curvirostra CORNELIUS, J.M.*; ZYLBERBERG, M.; BREUNER, C.W.; HAHN, T.P.; Univeristy of California, Davis; University of California, Davis; University of Montana; Univeristy of California, Davis cornelius@ucdavis.edu

We evaluated the relationship between hematozoan parasite load and potential predictors such as month, breeding condition, sex, molt, body condition and corticosterone levels in the nomadic and opportunistically breeding red crossbill, Loxia curvirostra. Many birds experience a relapse in parasite infection during breeding. Opportunistic species breed on schedules that differ from most birds and therefore offer a unique opporunity to investigate the relationship between reproductive condition, season, and parasite load. In red crossbills, we found a significant positive relationship between intensity of Haemoproteus infection and breeding condition in both females and males. Month contributed significantly to variation in parasite load, with the highest levels occurring from June through September, coincident with the potential summer breeding season. Red crossbills have a protracted breeding season when compared to most birds, and the period of increased parasite intensity is protracted as well. Sex, molt stage, hematocrit, body condition, and maximum or baseline corticosterone levels did not significantly contribute to variation in parasite load. It will be interesting to explore the relationship between breeding condition and parasite load during the short days of winter, when red crossbills opportunistically breed.