Meeting Abstract

P1.16  Thursday, Jan. 3  Avian malarial infection rates in expanding populations of the Puget Sound white-crowned sparrow (Zonotrichia leucophrys pugetensis) FOLTZ, S*; DAVIS, JE; WINGFIELD, JC; University of California, Davis; University of California, Davis; University of Washington; University of California, Davis; University of Washington SarahLFoltz@gmail.com

Species and sub-species tend to associate with specific habitats according to their physiological tolerances. Historically, the Puget Sound white-crowned sparrow (Z. leucophrys pugetensis) has shown a preference for breeding in low altitude coastal habitats in the U.S. Pacific Northwest. However, they have recently expanded their breeding range to high altitude areas associated with human disturbance, such as ski slopes, in addition to their lower altitude ancestral habitats. One hypothesis to explain this expanded breeding distribution is that high altitude sites afford some relief from disease and parasites, possibly by reducing population pressure or by providing a refuge from traditional disease vectors. During spring and summer of 2007, we collected blood samples from wild birds captured from six distinct breeding populations ranging over both low and high altitudes in western Washington State, as part of a larger study examining possible links between stress and reproduction. Blood samples were examined for evidence of infection by Plasmodium and Haemoproteus, two genera of malarial parasites commonly found in sparrows. As a measure of infection, we counted the number of red blood cells (RBCs) infected with each genus per 100 white blood cells (WBCs), as well as the frequencies of five types of WBCs (heterophils, eosinophils, basophils, monocytes and lymphocytes). Here we discuss the correlations between parasite load, altitude and WBCs.