Postbreeding Movements and Habitat Use of Adult Wood Thrushes in Northern Virginia

• Published in: The Auk 1999-04, Vol.116 (2), p.458-466
• Main Authors: J. H. Vega Rivera, McShea, W. J., Rappole, J. H., Haas, C. A.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal reproduction; Animal, plant and microbial ecology; Animals; Autoecology; Aves; Biological and medical sciences; Bird nesting; Birds; Deciduous forests; Deciduous trees; Forest habitats; Fundamental and applied biological sciences. Psychology; Habitat conservation; Habitat utilization; Habitats; Hylocichla mustelina; Male animals; Molting; Nesting sites; Ornithology; Regions; Riverine habitats; Vertebrata
• ISSN: 0004-8038; 1938-4254; 2732-4613
• DOI: 10.2307/4089379

We report movements and habitat use during the postbreeding period of radio-tagged adult Wood Thrushes (Hylocichla mustelina) at the United States Marine Corps Base, Quantico, Virginia, from May to October 1993 to 1995. Thirty of 61 radio-tagged adults stayed on the study area up to two months after they finished reproductive activities. During this time they underwent molt. Of these 30 birds, 11 (6 females and 5 males) molted in the same sites where they nested, 4 males moved to stands of deciduous saplings adjacent to their nesting territories, and 15 (4 females and 11 males) moved to molting sites 545 to 7,291 m from their nesting territories. We found no clear patterns that sex or reproductive success were related to the probability of moving away from nesting sites to molt, nor that the location of molting adults was correlated with the presence of fruiting plants. However, structural attributes of the vegetation that may enhance predation avoidance, such as the number of woody stems, the density of the understory, and the number of deciduous saplings, were significantly higher in molting sites than in nesting sites. We hypothesize that during molt, Wood Thrushes may need access to "safe havens" where protection from predators is enhanced. Our study strongly suggests that a conservation strategy that focuses on identifying and protecting nesting habitat is inadequate if the events and needs during the postbreeding period are not considered as well.