Maybe it's just because I have one in my yard, but it seems to me there has been a population explosion of hummingbirds here this winter, and not just the expected Rufous. A friend of mine reported that she had a Rufous and a Ruby-throated in her garden in Clear Lake. I've had other anecdotal reports from readers and "through the grapevine" about such birds. And yesterday, Gary Clark's Nature column in the Houston Chronicle was devoted to a report, with pictures, of a Calliope Hummingbird that is spending the winter at a suburban backyard in The Woodlands, just a few miles from where I live!
The Calliope is the smallest North American hummingbird at just 3.25 inches long. (The Ruby-throat and Rufous are each a half-inch longer which is a lot when you are talking about a bird this small.) It is a bird of the far Northwest in summer, but its migratory wanderings can bring it into our area. The one in The Woodlands, though, may be the first record for Montgomery County and they don't normally spend the winter here but in southern Mexico.
So far, we have had a very mild winter, with only two episodes of temperatures that got into the twenties. This is a stark contrast to our last two winters. The mild weather may account for some of the hummingbird lingerers, which brings up the question, how did they know it was going to be mild?
We have abundant evidence from around the world that birds are changing their ranges due to the warming global climate. Perhaps this is just another instance of that.