Male Anna's Hummingbird Changes into Adult Plumage

 Autumn changing into winter is not my favorite time of year. You can scarcely complain about the weather here in southern Arizona now in November, day after sunny day, the temperature a mild 80, but things are closing down, you can feel it. This past summer, for instance, we often went out after dark on our back porch as the evening cooled off, enjoying the nectar-drinking bats swarming around us and draining the sugar water out of the half-dozen feeders we put out daily for the hummingbirds. But by now our bats have returned to Mexico for the winter, and the porch is empty. And anyway the air is getting too nippy for us to go out at night.

All through the year we had been watching another gradual change, the hummingbirds (we have five species) giving over the rather plain plumage they started life with to don (the males, anyway) the startlingly beautiful breeding plumage they will put on to win the females with. That change is at its peak now. Let me show you step by step what one species can do. Here is the male Anna's Hummingbird in sub-adult plumage.

 

This is a totally plain hummingbird with almost nothing to distinguish it. But notice the black spot on the side of the throat; there is also one on the other side. That is what it starts with.

Now note the spot again. When you look at the spots from an angle, they appear black, but when they are exactly opposite to the observer, they shine up bright red. That "black" spot is actually red, and you can see that some other spots are beginning to appear on the throat, and you can see that they're going to be red too. Some black spots are also appearing on the back of the head, and they also will prove to be red.

 The red on the throat is gradually expanding.

Suddenly the entire head and throat (except for a white area around the eye) is bright red (though from this angle the crown and throat appear black). Note how what started as a small spot on the side of the throat has thickened into a flange which is beginning to stand out from the throat.

 

Here is how it would appear from a slightly altered angle.

And here finally is the fully adult male Anna's Hummingbird.