Behavioral ecology and population status of wood thrush and ovenbird in Great Smoky Mountains National Park

Reversing recent declines of Neotropical migratory landbird populations in eastern North America will require more comprehensive and rigorous techniques for assessing the status of breeding populations. My dissertation research focuses on: (1) how additional breeding attempts (renesting and multiple brooding) and pairing success influence population growth rates, and (2) experimentally testing how parental care affects nesting success under conditions of varying food availability.; In 1999–2001, I monitored 288 nests of the Wood Thrush ( Hylocichla mustelina) and Ovenbird (Seiurus aurocapillus ) in Great Smoky Mountains National Park, ascertained the pairing status of 326 Ovenbird males, and sampled parental behavior of both focal species at 50 food-supplemented (treatment) and 62 control nests.; From my empirical data and indirect estimates, I calculated a finite rate of Ovenbird population increase of 0.94. However, Ovenbird populations in the park do not appear to be declining rapidly, and pairing success may be higher and additional breeding attempts more common than previously thought, which may compensate for low rates of annual fecundity.; My findings linking parental care to reproductive success and food availability were similar for both Wood Thrush and Ovenbird. Food-supplemented nests had higher daily survival rates, higher productivity and parental attendance, shorter nestling periods, and heavier nestling prior to fledging, despite the fact that feeding rates were similar at treatment and control nests. I concluded that parental behavior, mediated by food availability, has adaptive significance in Wood Thrushes and Ovenbirds because it improves their reproductive success when food is abundant.; Food supplementation is rarely applied to insectivorous passerines because of the practical difficulties of provisioning wild birds. I provided mealworms on feeding stations made of plastic transparencies covered with a thin layer of green moss. The method was effective for both Wood Thrush and Ovenbird. Overall, 84% of tested breeding pairs used supplemental food, and very few mealworms were taken by non-target consumers.