Thursday, February 25, 2010
I'm hoping "our" pair will nest in one of our trees this year. A few years ago they began building a nest at the end of one of the branches near the top of a live oak tree that overhangs our driveway. We watched for several days as the pair attached several long pieces of grass that hung down a couple of feet from the slender forked branch. They wove other grasses and plant material horizontally around those vertical pieces, starting from the top.
As the Altamira Orioles continued construction, Bronzed Cowbirds acted like building inspectors. (The cowbirds here are a real nuisance to other nesting birds, parasitizing the nests of orioles as well as cardinals, thrashers, and other birds. They are especially troublesome to Hooded Orioles.) After a few days the orioles abandoned that nest and started building another nest in the same tree. This nest, too, was abandoned. Neither nest was ever completed. Each was woven about six inches long with the longer vertical strands of grass never joined at the bottom of the nest. (Completed nests I've seen are all at least a foot long and sometimes two.) I wondered if the abandoned nests were decoys to distract the parasitic cowbirds from the "real" nest built later in a neighbor's ash tree. Or maybe this was a young pair of birds who had to make a couple of false starts before they got it right. Or perhaps that location just didn't seem right.
All summer long the large pendulous nest the Altamira pair finally completed was clearly visible overhanging a neighbor's drive. And hanging down about twenty feet from beneath the nest was a piece of garden twine that the birds had stolen from the neighbor's greenhouse! Apparently they couldn't break it off into smaller pieces, so the long trailing end of it was left to dangle to the ground. A few weeks later two new orioles were fledged from that most unusual nest.
Altamira Orioles are daily (or hourly or sometimes minutely!) visitors to our nectar feeders and also eat nectar from the aloe vera that blooms in the late winter and spring. During the winter the Altamiras also frequent the seed feeders, the only orioles I have ever seen eating seeds.
The song of the Altamiras is very loud and musical, kind of like someone whistling. One echoes the other as they sing and call to each other from yard to yard. Sometimes you can hear one, if you are close enough to it, practice a little "whisper" song, a very very quiet song but long and complex. The first time I heard one doing this, it was perched on the outside of an upstairs window, presumably whispering to its reflection.