BAY-BREASTED WARBLER(Setophaga castanea)

The Bay-breasted warbler is hard to localize and identify because it has the habit of perching in the thick of conifers. It is also similar to the Chestnut-sided warbler, but the latter has a white breast and a yellow crown, and the bay or chestnut color appears only as two narrow lines along the breast.

The birds is around 13 cm (5 in.) long. The breeding male has a black face and chestnut or bay head and breast, and this color extends down the sides of the breast as well. It has two white bars in the grey wings. There’s a cream patch on the neck side. The under parts are creamish. The bill and legs are black. Females have some chestnut-bay color on their sides. The face is grey and the back grey-olive green, and they have two white bars on their grey wings. The bill and legs in the female are grey.

There are known hybrids between the Bay-breasted warbler and the Blackpoll warbler, a closely related species. It can also hybridize with other warbler species such as the Yellow-rumped and the Blackburnian warblers.

Warblers are thus called thanks to their generally melodious songs. The genus Latin name ‘setophaga’ means ‘moth eating’, and ‘castanea’ refers to the chestnut color of the plumage.

The bay-breasted warbler breeds on PEI, and its overall breeding range encompasses the Canadian boreal forest, especially spruce and fir. It is fairly common on the island in the spring and summer. The wintering range of this species includes part of the Caribbean, southern Central America and the northern tip of South America.

The Bay-breasted warbler feeds on insects and spiders in the summer, and fruit in the winter.

Conservation: although the Bay-breasted warbler is not on any list of threatened species at the present time, its numbers have declined sharply over the last few decades – by some 70%. This number also fluctuates in relation to spruce budworm infestations, as that pest is part of the bird’s diet. This negative trend in the population appears to be related to spruce budworm spraying and lost of wintering habitat.

Bay-breasted warbler, breeding male - Rondeau Provincial Park, Ontario - photo by Mdf
Bay-breasted warbler, breeding male – Rondeau Provincial Park, Ontario – photo by Mdf
Bay-breasted warbler, female - photo by Dan Pancamo
Bay-breasted warbler, female – photo by Dan Pancamo