Wilson's WarblerCardellina pusilla
A small and spritely warbler that moves actively in bushes and trees, often flipping its longish tail about as it hops from branch to branch. Typically stays low in semi-open areas, avoiding the interior of dense forest. Although it nests from coast to coast across Canada, Wilson's Warbler is far more common farther west. In the East it is seen in small numbers, but in the Rockies and westward it is often the most abundant migrant in late spring.