Natural Resources, School of

 

Date of this Version

2002

Citation

The Auk 119(1):109-124, 2002

Comments

This article is a U.S. government work, and is not subject to copyright in the United States.

Abstract

We monitored adult and juvenile breeding-season movements and habitat use of radio-tagged Wood Thrushes (Hylocichla mustelina) at the Piedmont National Wildlife Refuge, central Georgia, USA. We investigated the effects that management for Red-cockaded Woodpeckers (Picoides borealis), thinning and burning >30 year old loblolly pine (Pinus taeda) habitat, had on Wood Thrushes, a ground-foraging and midstory-nesting species. Adult Wood Thrush pairs regularly moved long distances between nesting attempts (range 1 to 17,388 m). The only experimental effect we found on adult movements was a decrease in weekly emigration rates (AP) from thinned and burned compartments after silvicultural management. Adult males preferred riparian hardwoods with sparse to moderate cover and those preferences increased following management. Juveniles remained near their nest site (x = 177 m, SE = 113) for an average 24 days (SE = 6.3), and then dispersed a mean 2,189 m (SE = 342). Before dispersal, juveniles preferred upland hardwood-pine mixed habitat (P < 0.05) with moderate overstory cover (P < 0.05). We found no management effects on dispersal distances or predispersal habitat use. However, juveniles from thinned and burned compartments dispersed to hardwood habitats with dense cover, whereas birds from control compartments dispersed to pine-dominated habitats with sparse cover. All juveniles dispersed to areas with habitat similar to what they used before dispersal. Small-scale thinning and burning for Red-cockaded Woodpeckers may have had little effect on Wood Thrush habitat use and movements because typical movements were often larger than the scale (stand or compartment) targeted for management.

Monitoreamos con radio-telemetria los movimientos y el uso de habitat durante la 6poca reproductiva de adultos y juveniles de Hylocichla mustelina en el Refugio Nacional de Vida Silvestre Piedmont, en Georgia central, EEUU. Investigamos los efectos que tiene el manejo del bosque (entresaca y quema de hibitat de Pinus taeda con mas de 30 anios de edad) orientado a la conservaci6n de Picoides borealis sobre H. mustelina, una especie que se alimenta en el suelo y que nidifica a media altura del bosque. Las parejas adultas de H. mustelina por lo general se movieron largas distancias entre los intentos de nidificaci6n (rango 1 a 17,388 m). El uanico efecto experimental que encontramos en los movimientos de adultos fue una disminuci6n en las tasas semanales de emigraci6n (T) desde los sectores entresacados y quemados luego del manejo silvicultural. Los machos adultos prefirieron los bosques riberefios con poca a moderada cobertura, y estas preferencias incrementaron luego del manejo. Los juveniles permanecieron cercanos al sitio de nidificaci6n (x = 177 m, ES = 113) por un promedio de 24 dias (ES = 6.3) y luego se dispersaron una media de 2,189 m (ES = 342). Antes de la dispersi6n los juveniles prefirieron habitat no-ribereiio mixto de bosque y pino (P < 0.05) con moderada cobertura del dosel (P < 0.05). No encontramos