Meeting Abstract

47.11  Jan. 6  The effects of timber harvesting on growth and stress hormone levels in nestling Prothonotary warblers (Protonotaria citrea) BECK, ML*; SCHWABL, H; WEBSTER, MS; Washington State University; Washington State University; Washington State University beck@mail.wsu.edu

Anthropogenic habitat fragmentation and modification are becoming increasingly pervasive problems for many natural populations. Habitat fragmentation or reduction may have drastic effects on a population by greatly reducing the number of individuals or their reproductive success. However, less drastic habitat modification may have more subtle effects that are only detected by examining a population in detail. More subtle effects of habitat modification could include differences in the stress response or changes in the development of young. We examined the effects of habitat modification on nestling growth and condition in the Prothonotary warbler (Protonotaria citrea). In our case, habitat modification was defined as areas in which timber had been harvested in the last 10 years in a manner that thinned the forest by 40-60%. We predicted that nestlings raised in areas where timber was harvested would be in worse condition, less mature at fledging, and grow at a slower rate than those raised in unharvested areas. We further predicted that nestlings in harvested areas would have higher levels of corticosterone than those raised in unharvested areas. We found no significant differences in growth rates, condition, or maturity of nestlings in the harvested and unharvested areas. Furthermore, stress hormone concentrations did not differ significantly between nestlings raised in the harvested and unharvested habitats. Our results show that prothonotary warblers are not negatively affected by thinning the forest surrounding their breeding sites. However, forest thinning that encompasses the aquatic areas in which they nest may negatively affect the birds as they strongly prefer to breed in shaded areas.