Meeting Abstract

P2-147    Comparative physiology of two breeding cardinalid species in northeast Arkansas Krajcir, KJ*; Donahue, ER; Terry, JL; Neuman-Lee, LA; Boves, TJ; Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401; Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401; Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401; Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401; Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401 kjkrajcir@gmail.com

Adult birds partition finite energy resources among daily activities (e.g., foraging, immunity, preening) and major life history events (i.e. reproduction, molt, and, for some, migration). In addition to expected events, energy may be mobilized in response to unpredictable stressors (e.g., infections, adverse weather, human disturbance). However, individuals may not sufficiently respond to such perturbations if energetic resources are lacking. To explore the relationships among life history strategies (e.g., migratory status), sex, symbionts, and host physiology, we measured: (1) how physiological metrics varied between two closely related birds with unique life histories and (2) how ectosymbiotic feather mites influences their host’s condition. To do this, we sampled blood from breeding males and females of two species in Family Cardinalidae with different migratory strategies - Cardinalis cardinalis (Northern Cardinal; a resident species) and Spiza americana (Dickcissel; a Neotropical-Nearctic migrant). Both species are common breeding birds in the Arkansas Delta region, which has been heavily modified for agricultural use. We conducted differential white blood cell counts and bacterial killing assays to assess aspects of immunity and stress physiology. We also censused feather mites on the flight feathers. We found interspecific differences in immune abilities but no such difference between the sexes. We also found evidence that some birds appear to be chronically stressed in this environment. Feather mite abundances varied within and between these species, but mite load was unrelated to host physiology. This study provides some insight into how these birds respond to the unique challenges they face.