In Arizona in late November, we spent time each day photographing warblers in what I called the Warbler Tree, a Cottonwood on the edge of a pond that was attracting lots of the tiny birds. The reason for their presence in the tree was the abundance of aphids which in the first image are visible as black dots on the leaves at the upper left and in the second image on the leaf by the warbler’s beak. Late one afternoon, a Tennessee Warbler feasted on the aphids showing off its acrobatic abilities by hanging upside down in order to reach the tiny insects.