Thursday, February 3, 2011

Freezing Hummingbirds

With the low forecast for 20°F in Tucson, I brought the hummingbird feeders in last night and then set my alarm for 6:45 a.m. (sunrise at 7:17) to set them out again. With very flat topography and virtually no gradient towards the Rillito River, this part of north-central Tucson is a cold sink, almost always about 5-7 degrees colder than the official low each day, and my 3-parts-water-to-one-part-sugar concentration starts to freeze somewhere between 26 and 28°F.

The official low temperature this morning was in fact 18°F, and with the gusty winds we had stirring things up all night and into the morning hours, we had exactly the same temperature at 3919 N Vine Ave.

Some Anna's Hummingbirds were already starting to chip and hover over the feeder sites when I began hanging the feeders, and the Violet-crowned Hummingbird appeared right at 7:00 a.m. Within an hour, the sugar water began to freeze, so I had to go out and add a little bit of hot water and shake them up until the sun got on them.

This Anna's Hummingbird has an unusual pattern of iridescence on the throat. I'm not certain if it's a male still molting in its helmet or if it's an older female. Most young males that have this much red in the gorget won't have it so symmetrical and will also have patches of elsewhere in the face and on top of the head, and most of them have virtually all of their adult plumage, so I suspect it's a female.

These are male Anna's Hummingbirds. I'm guessing around 20-40 different individuals utilize the yard's feeders, but that may be an underestimation.

The Broad-billed Hummingbirds were the last to wake up and begin defending their feeders. There are at least two territorial males and 4-6 additional floaters (or more). This guy was still trying to get warm in the sun and let me approach within a few inches while keeping his eye on the feeder.

Finally, here's a series of digiscoped shots of the Violet-crowned Hummingbird from this morning. He first showed up October 16 this year, has occasionally left the yard from two days to three weeks at a time but has been back now for two weeks and defends two feeders full time. He allowed much closer approach this morning, choosing a new perch in the open that allowed him to view both feeders at once. I think he know how important the food supply was in weather like this.

The forecast low for Tucson is 18°F tomorrow morning...and no wind. So we could very well get down to the low teens. The coldest temperature we've had here in the nearly 13 years I've lived here was 17°F on January 15, 2007.

1 comment:

  1. Great shots! Up here in Oregon we also have Anna's hummingbirds through the winter. I don't have a feeder out, but one spends most of its time in mine and my neighbor's trees. I've seen it drinking from old flowers I left in the garden over the winter.