Meeting Abstract
P2.15 Sunday, Jan. 5 15:30 Behavioral and Physiological Response of Red-winged Blackbirds to Perceived Risks during the Breeding Season REED, W.; MAHONEY, J.*; LINZ, G.; North Dakota State University, Fargo; North Dakota State University, Fargo; USDA, APHIS, WS, and National Wildlife Research Center, Bismarck, North Dakota jessica.l.mahoney@my.ndsu.edu
The fitness costs of reproduction include trade-offs between current and future reproduction that must be addressed each breeding season by parental generations. Within a current mating season, risks include decreased survival or decreased self maintenance, and decreased survival of offspring through predation or brood parasitism. The red-winged blackbird (RWBL) is a polygynous bird that has become a classic model of mate choice and reproductive biology for free living species. The long term objectives of this study are to evaluate how female RWBLs assess and respond to combined risks associated with the breeding season by examining female mating choices. The focus of this study was to examine how RWBLs respond to the perceived risk of predation and parasitism across the breeding season. I presented breeding colonies with effigies and calls of either a great horned owl, sharp-shinned hawk, female brown-headed cowbird, purple martin (effigy control), or a control (no effigy) at the start of the nesting period and 18 days later. I measured RWBL interactions with the effigies such as alarm calling and attacking effigy, and collected the second egg in each nest to evaluate yolk corticosterone levels. I predicted that colony response to perceived predator risk would be greater than response to parasites or control treatments, behavioral responses would decrease across the season, and yolk corticosterone levels would be elevated in eggs from females exposed to predators. Results suggest that RWBLs do have a greater response to the perceived risk of predation than to the parasite or control treatments regardless of the timing of predator exposure.
