Wood Thrush nesting in Pennsylvania.
Photo: Thomas Bollinger, USFWS
During its breeding season (May-July), the Wood Thrush is found in mature, deciduous and mixed forests of the eastern United States and southeastern Canada. Wood Thrush are sensitive to changes in habitat area, habitat quality, and soil chemistry. They are most productive in large forest tracts with diverse structure, including a mix of large and small trees. Nests are placed in understory shrubs and trees and Wood Thrush forage for invertebrates in moist leaf litter. After the breeding period, adult Wood Thrushes and their young move into sapling-dominated areas, where they molt and build fat reserves for migration.
Recent studies have found that forest loss and degradation on the breeding grounds result in poor breeding productivity and is a primary driver of declining population trends. Specifically, each 1% loss of forest habitat on the breeding grounds results in a 0.62% annual population decline. During the past five decades, habitat for breeding Wood Thrush has been lost or degraded through two primary mechanisms: 1) deforestation, owing to human development and agriculture and 2) changes in forest configuration, structure, and composition caused by widespread even-aged forest management practices and species interactions like deer overbrowsing. These processes produce numerous negative effects that result in population threats, such as greater nest predation and Brown-headed Cowbird parasitism. Findings emphasize the importance of maintaining adequate amounts of high-quality breeding habitat on the landscape.
The Alliance and its partners seek to protect and enhance Wood Thrush breeding habitat through projects focused on:
Limiting forest loss and fragmentation, especially in the Appalachian Mountains region where more than 70% of the global population breeds
Improving existing habitat by implementing sound silvicultural practices (link to new NE/Mid-Atlantic guidelines) to increase forest structural and age-class diversity
Working with private landowners, especially land trusts, where 85% of Wood Thrush breed, and
Conducting and supporting research focused on the threats and breeding season requirements of global Wood Thrush populations (link to Rushing et al papers).