The Tennessee Warbler is a small bird that breeds in Canada’s boreal forests. Breeding males show a gray head and pale eyebrow, while females and nonbreeding birds look more yellow-green overall.
A breeding male has a yellow-green back, gray head, pale eyebrow, and light underside. Females and nonbreeding birds look more yellow-green overall; white undertail feathers are a useful field mark.
Some Tennessee Warblers pause during autumn migration to replace their feathers. At one southern Quebec stopover, researchers tracked 18 moulting birds and four that had finished moulting. Moulting birds stayed about 46 days on average, compared with about eight days for post-moult birds, spending much of the stopover on feather replacement.
The tracked birds used overlapping home ranges averaging roughly 15 hectares, and habitat use was associated with forest cover and edge. Moulting birds arrived around 2 August on average, while post-moult birds appeared around 12 September. Forest patches in peri-urban landscapes can host warblers for much of the moulting period.
An extinction-risk assessment has not been added yet.
At the southern Quebec stopover, moulting warblers stayed about 46 days and used home ranges of roughly 15 ha associated with forest cover and edge. Protecting forested stopovers includes places where migrants remain to complete their moult.