Here’s an example of one of the countless thousands of questions that are still out there waiting to be answered about North American birds. I went to Texas in February (for the opening of the fantastic new Clif Moss Nature Education Center of the Corpus Christi Public Library) and I had a chance to see some Wild Turkeys nearby. As expected they had whiter tips on all the body feathers than northeastern birds, but they also seemed thinner and smaller-headed than the Turkeys that frequent my backyard in Massachusetts, and when I got home I immediately saw what the difference was.
The Massachusetts Wild Turkeys have feathering extending all the way up the neck, while the Texas Turkeys have a long stretch of the upper neck bare (here’s a quick sketch I did that first morning at home). This is logical, presumably an adaptation to the cold weather in Massachusetts, but in a quick review of some sources (the BNA account) I found no mention of neck feathering as a geographic difference. I thought maybe it was just a winter feature; maybe the Texas birds had already lost their “winter coat”, and the Massachusetts birds would lose their neck feathers for the summer. They may still do that, but as of today (2 April 2008) they look the same.
As usual, this just brings up more questions: Is this going to be true year-round? What are the patterns of variation? Do all southern birds – Florida, Texas, Arizona – lack neck feathers? Does it change gradually from north to south or is the change more abrupt? and lots more….