Bay-breasted Warbler, Setophaga castanea
My first ever Bay-breasted Warbler at Peach Hill, Poughkeepsie, NY
With their navy blue masks, rusty red throats and caps, and peachy creme flanks, Bay-breasted Warblers are uniquely colored amongst the rest of the eastern wood-warblers. I love watching them among the flowers, as their color palette contrasts wonderfully with the lighter pastel colors of spring.
To me, Bay-breasted Warblers feel like one of the harder warbler species to find. I missed them completely the first year I was birding, and I always feel like it is a big deal when I do see one. They tend to arrive in the later waves of warblers, and are an uncommon bird.
Perhaps one of the reasons it feels harder to find Bay-breasted Warblers during migration is that their populations tend to be dependent on the abundance of spruce budworms. These warblers love the pupae and larvae of these insects. When there is an abundance of spruce budworms, the population of Bay-breasted Warblers increases alongside them. They are smart about their budworm foraging, and will feed in middle levels of trees as well as higher levels to avoid competing with other spruce budworm feeders such as Cape May Warblers. They can be aggressive though, and will attack Blackburnian Warblers if they are both feeding in the tops of trees.
Even though populations of Bay-breasted Warbler are currently more or less stable, it is difficult to keep an accurate tab on them because of their remote breeding locations. Moreover, habitat loss from deforestation and pesticide use on their wintering grounds in the tropics as well as boreal habitat loss due to climate change and deforestation suggests that this bird is in trouble, even if numbers do not show it yet.
Bay-breasted Warbler at Magee Marsh during the Biggest Week in American Birding 2019.