Tree Swallow are dying because of our cold, wet weather. There have been email reports of birds found dead. This species feeds exclusively on flying insects. Searching Google for an explanation of why some insects fly above water, say in a pond, where you often see swallows feeding, I came up with nothing definitive. My guess is that the water at that moment is warmer than the air, creating a layer of warmer air that attracts insects. Don't quote me on that. In any case, a cold rainy day will ground insects. Swallows can starve. Purple Martins have the same problem, although I've not yet seen reports of returning martins.

Our hummingbird feeder awaits its first visitor. As you can see in the photo, it's a good thing those birds haven't arrived yet.