Movement and territoriality of wintering Hermit Thrushes in southeastern Louisiana

We describe the spatial organization and social behavior of Hermit Thrushes (Catharus guttatus) wintering in pine plantations and an adjacent hardwood forest in Tangipahoa Parish, Louisiana over three winters. We used point c ounts (n = 403) to collect data on agonistic behaviors and relative abundan ce within the study area. We used mist-netting to study site fidelity on fo ur 9-ha plots within and among years. We used radio-telemetry to measure He rmit Thrushes' movements and territoriality (n = 50). We found that Hermit Thrushes saturated suitable patches within the study area. Most Hermit Thru shes actively defended small [mean = 0.55 +/- 0.03 (SE) ha], minimally over lapping (15.90 +/- 3.63%) territories throughout the winter. Hermit Thrushe s established and maintained territories using the same agonistic behaviors described for breeding birds. A few non-territorial birds (14%) moved amon g occupied territories, but most were faithful to a larger neighborhood, ap parently awaiting a territory vacancy. Territorial behavior and frequency o f non-territorial birds did not differ among age and sex classes, suggestin g the absence of a sex- or age-based dominance hierarchy. The behavior of H ermit Thrushes conformed to the emerging view that competition for spatiall y mediated resources on the wintering grounds, such as food or cover, contr ibute to limiting populations of many species of migrant passerines.