December 23, 2004
Things that make you go humm...
The earliest known record for Anna's Hummingbird in Oregon is Dec 1944, North Bend, Coos Co. The next bird didn't materialize until Dec 1958 when a single bird wintered in Ashland, Jackson Co. A rapid expansion throughout w. Oregon occurred between 1964 and 1970. Many of the earliest reports were from feeders in Portland, Multnomah Co. and were, probably, biased toward observer concentrations.
The one real constant for Anna's Hummingbird records in winter was bird feeders or, at least winter gardens. But that has been breaking down in the past few years. More and more birds are being seen well away from feeder or even flowers.
Today, for example, I found two Anna's Hummingbirds well away from anything remotely residential. The first was a hatch-year male, singing happily from the top of a young Red Alder. The second, a hatch-year female, seemed very out of place in the middle of a stand of mature Sitka Spruce and Red Alder. It was associating with a fairly typical feeding flock of winter passerines that included Black-capped and Chestnut-back Chickadees, Golden-crowned and Ruby-crowned Kinglets, Hutton's Vireo and Townsend's Warbler. The hummingbird's association with a winter feeding flock is interesting since all these species gang together to feed primarily on insects.
The prevailing assumption has been that wintering Anna's are heavily supplimenting their diets with insects, so associating with an insect foraging group makes sense. It's the roving part that's a bit surprising since these feeding parties do a lot of traveling throughout the day. I expect hummingbirds to set up territories.
You live, you learn.
Posted by mbalame at December 23, 2004 1:31 AM