Bay-breasted Warbler

This fall is a banner season for Bay-breasted Warblers. I saw and/or banded 24 of them from 21 August to 30 September 2018 (when I took the bottom photo). In the 2017 fall I only counted seven and in the 2016, only one. A lot of spruce budworms must have hatched in their northern breeding grounds.

Fall Bay-breasted Warblers are hard to tell from Blackpolls. If you have them in the hand, Blackpolls have yellowish toes; Bay-breasts have black toes. Sometimes in the field (and especially in the hand) look for the Bay-breasted Warbler’s faint bay tinge to their flanks. You can just about see this color in the lower photograph. Although Blackpolls are common in the spring, since 2008 I have only seen three in the Fall here in Northfield. Curiously, in the spring, my Blackpoll records outnumber my Bay-breasted Warbler sightings. Studies suggest that Blackpolls migrate southeast to Nova Scotia before making an overwater flight to northern South America. Their return trip in the spring brings them though Central America and the central United States (Deluca et al. 2013). This hypothesis would explain why I find so few fall Blackpolls.