Townsend’s Warbler (Setophaga townsendi) is not rare in North America but it is not often seen as far east as Calgary. It usually breeds in the Pacific Northwest (Alaska, British Columbia, Washington and Oregon) and winters in Mexico or on the western edge of California. However, the eBird map for Townsend’s Warbler shows a few sightings on the east coast of the United States and Newfoundland.
Through my dining room window, I glimpsed a little grey bird (most little birds look grey from far away) flitting from branch to branch in my neighbour’s tree (I think it is a Bay Willow, a.k.a. Laurel Leaf Willow or Salix pentandra, with hail-damaged leaves). After I grabbed my camera, the little bird was still there. I waited for it to flit onto a non-leaf-camouflaged branch. It obliged me for 20 seconds, explored a few more branches, then disappeared.
Townsend’s Warblers, like most Wood Warblers, eat mostly insects. They glean insects from leaves and needles in the upper third of tall deciduous and coniferous trees. This is likely what the warbler I was spying on was up to. Wood Warblers (New World Warblers) don’t actually warble. They were named after the warbling Old World Warblers which they resemble somewhat in appearance and diet but are not related to genetically.