Excerpts from Jim Conrad's
from the September 18, 2005 Newsletter issued from the Sierra Nevada foothills
somewhat east of Placerville, California, USA
GNAT-EATING ANNA'S HUMMINGBIRD
After the wind settled a bit, hoards of gnats began lifting from grass along the pond's banks, sunlight catching in their filmy wings. These were not the gnats I told you about last weekend, the ones that get into our eyes and ears, so I didn't pay much attention to them... until a hummingbird came and began snatching those gnats in mid-air.
Hummingbirds don't just eat flower nectar and sugar- water in people's feeders. If you think about it, it's easy to see why this true. Nectar contains relatively little protein and sugar-water offers none, and a hummingbird needs protein like any other animal. Gnats make a good source of protein to a hummingbird with such a tiny throat.
So, for a solid three minutes that hummingbird darted about inside the diffuse cloud of rising gnats, nabbing a gnat about every five to ten seconds. It was either a female or an immature male Anna's Hummingbird, CALYPTE ANNA, our most common species among the four species possibly found here. You can see it at http://www.briansmallphoto.com/gallery/anhu.html.
I've not spotted any of the other three species at this location, though they may have zipped by without my catching their distinguishing field marks. Anna's is the one that comes to the feeder and behaves pretty much like the hyperactive, fast-zipping, feeder-mobbing Eastern Rubythroat. In fact, it's just possible that this Anna's Hummingbird is even a bit more rambunctious and show-offy than the Rubythroat.
The Anna's looks very much like the Rubythroat, except that it's noticeably larger, and the red of the throat extends clear over the forehead. A Rubythroat's forehead is dark green. Also, a Rubythroat makes rapid, squeaky chipping sounds but has no real song, while it's not uncommon to find a male Anna's atop a branch actually singing. You can hear the Anna's soft, bubbly, squeaky very complex song at http://naturesongs.com/anhu5.wav.
Maybe the Anna's is more territorial than the Rubythroat, too. There's a certain dead tree snag between here and the mailbox on which many times this summer I've found a male Anna's singing his song in the exact same spot day after day. I've never seen a Rubythroat do that.