Male Yellow Warbler

Katie and I drove out to the end of the refuge to set our first mongoose traps of the expedition Saturday afternoon 14 March. We parked our vehicle under my favorite acacia tree and were immediately greeted by this seemingly friendly male yellow warbler. Upon further consideration however, we realized that welcoming committees are generally restricted to the human species and this guy had something entirely different in mind. Can you guess what was on his mind as he attacked the glass of our vehicle and the rear-view mirror?