I was at a friend's house last night watching her feeders. She has a small cherry tree with blossoms that is the holding area for for birds waiting to get to feeders.
The tree was filled with a couple of male rose-breasted grosbeaks, a male oriole, and a chickadee. All of a sudden a small yellowish bird flew right at one of the male grosbeaks. Binoculars revealed a textbook male cape may warbler. The two birds fluttered against each other and went their separate ways. Within minutes a cape may male (presumably the same one) returned and hopped to each flower to feed. When the cape may caught sight of the chickadee feeding about two feet away, it immediately flew over and attacked the chickadee. Both birds fluttered to the ground and for a moment the cape may had the chickadee pinned on the ground and then the chickadee flew away. The cape may continued to feed and was only distracted when a second male cape may entered the cherry tree, and both birds chased each other around in flight--at one point flying eight times around the cherry tree. I had never witnessed such aggressive warbler behavior towards other bird species when not on a nest. My guess is that with the cold weather and lack of insects, the food was at a premium and the warbler didn't want to share the source (although chasing and fighting other species would seem inefficient and waste energy). The cape mays moved on, as I spent the night and didn't see or hear them in the yard this morning. I would be curious if anyone has witnessed any warbler altercations with other species during migration. -- Sharon Stiteler Uptown, Minneapolis
