My field is alive with the sound of birdsong. It has been every evening for months and I’ve just figured out what bird is creating this wondrous melody. When I first heard it I was on my way out just as it was getting dark. The whole field seemed in the middle of a symphony, with notes popping up everywhere, and I was mesmerized for several minutes. I asked my friend, an expert birder, what species she thought it was. Based on my pathetic attempts to describe the song (and probably things like the habitat I described and the time of year), she suggested a yellow-rumped warbler or the ruby-crowned kinglet.
I assumed it was a one time show, that the birds were migrating, but soon came to realize that I was hearing it every evening as I closed the chicken coop or was heading out for an evening engagement. A good naturalist would have gone early to the show and waited patiently to catch a glimpse of the singers. My excuse is I’m still a practicing naturalist that errors on the side of warmth and comfort perhaps a little too much. The show always starts during my dinner prep/cocktail hour/might even be in my pajamas already time of day and I just never make it out to investigate. I could also truthfully argue that I cannot see well at dusk making any attempt to sit in a cold field futile anyway.
Well, I serendipitously caught a glimpse of a kinglet out my window yesterday and now I am convinced that kinglets are the players in my symphony. Going to Cornell Laboratory’s Ornithology site I can quickly confirm the sound that I hear: http://www.allaboutbirds.org/guide/Golden-crowned_Kinglet/lifehistory
But wait a minute. My friend suggested the ruby-crowned kinglet, and the little guy I saw outside my window – which I immediately recognized as a kinglet from our days in Houston – was wearing a yellow crown. And if my memory is correct, the golden crown had no orange tint to it, indicating that the kinglet was a queenlet, well, indicating I saw a female kinglet.
I listened to calls and songs from both species at the Cornell site and on my Peterson bird app. Since, it is winter and not breeding season, I focused on the calls. Birdsong is considered more complex and mostly done by males during courtship and mating. Calls are made for alarm or to keep a flock in contact with its members. Do they know that many members calling to each other creates a magical music show to the human hear? I wonder what it sounds like to them. I am almost convinced the call of the golden-crowned kinglet is the better match than the ruby-crowned kinglet, but I find the distinction between the birds’ sounds not discreet enough to be convinced.
If you read last week’s blog entry you will recall that I am fascinated with animals’ abilities to survive winter temperatures. How does the kinglet, a mere six grams of flesh and feathers, survive the winter? They are quite common in the extreme winters of the north. I dug out and am thoroughly enjoying a book I bought years ago in Maine: Winter World (2003) by Bernd Heinrich. In it Heinrich gives an engaging account of how he tried to answer this very question. Until his research, kinglets were thought to survive mainly on snow fleas in the winter. Heinrich sampled the stomach content of several kinglets and found no snow fleas, but lots of caterpillars. He was amazed because the birds had been foraging at the tops of trees in the winter. How were they finding caterpillars, thought to overwinter in pupa form or underground?
Heinrich next spent several winters collecting insects from treetops in a very sophisticated manner, hitting them with a club and collecting the fallen insects. He was amazed again; he found caterpillars. The next part of his story amazes me. He proceeded to collect and raise these frozen caterpillars in order to identify them. He did not give up when failure struck: one year a spider ate all the happily growing larva; and another year a lone surviving caterpillar pupated and then drowned in the glass because of condensation that formed on the jar sitting on a sunny windowsill. He did not quit, and in the third year he managed to raise to emergence a moth known as the one-spotted variant, Hypagyrtis unipunctata. I am in as much awe in what Heinrich learned as I am in his diligence. This is the beauty of science and the magic that drives all the men and women working on answering their own questions of wonderment. You can read about Heinrich’s study here: http://birdnote.org/show/kinglets-winter and here: http://www.npr.org/templates/story/story.php?storyId=1177500
As a scientist, albeit one with no where near the diligence – or cold tolerance – of Heinrich, I know that seeing one golden-crowned kinglet is not proof that there is a large group of them conducting a symphony every evening. Unfortunately I will have to don some warm clothes, boots, and binoculars and situate myself out in the field to listen quietly, and hopefully get a glimpse of the players in my show. I sure hope the show’s playing through March.