Dawn Chorus Birdblog: The Dawn Chorus
Sat Apr 26, 2008 at 06:03:20 AM PDT
Even by birders' standards, I'm a really early riser. When this goes up around 6am (SF time), I've usually been awake for an hour or two. The hours before sunrise are a wonderful time of day; the world is silent, calm and cool. At 4 am, you pretty much have the place to yourself. But in mid-late spring, you start noticing that you have company around 4:30. By sunrise, you're surrounded by others, all with plenty to say.
And not a human in the bunch. This is the hour of the Dawn Chorus.
Note: All of the links below should pop up in a separate window, so you can listen and read at the same time.
Pretty much everyone likes birdsong (with the possible exception of 3 a.m. mockingbirds), but few experience the Dawn Chorus these days. If you're fortunate enough to be awake before dawn without having to scramble off to work, it's wonderful to listen the birds wake up and say hello.
One of the earliest voices in any chorus is the American Robin, who typically start singing a half hour or more before sunrise. As one of the most widespread species in North American, they will be the anchor of the dawn chorus almost anywhere in the country.
Depending on your location, other voices will soon join in. In both my urban neighborhood and at our family cabin in the Santa Cruz mountains, one of the next voices to chime in is the Dark-eyed Junco. In the city, they are joined by mockingbirds, White-crowned Sparrows, California Towhees and occasional migrants passing through. Down in the Santa Cruz mountains, Black-headed Grosbeaks and Western Tanagers add their robin-reminiscent songs to the mix, along with Pacific-slope Flycatchers, Brown Creepers, Hutton's Vireos and the ever melodious Steller's Jay.
While looking for these clips, I found a nice set of dawn chorus recordings from around the country here, among them the Adirondacks (with American Robin and White-throated Sparrow), Dakota (doesn't say whether it's North or South, but it does feature Western Meadowlarks... always worth listening too), and the Everglades.
So why sing at dawn, anyway? Well, one reason is to let the others know that you made it through the night and you're back to face another day of protecting your territory. Dawn singing reaches its peak while birds are trying to set up territories and attract mates, though the birds do continue to sing throughout the day as they run off new challengers and intruders.
One other reason for the very early song is that it's a way of showing fitness to any nearby females who might be seeking a mate. "Look, I made it though the night with energy to spare! I can't even start looking for food for another hour, but I have the stamina to sing for that whole time without refueling". It means that he's healthy and pretty successful at finding food (implying that he has a good territory) - good reasons for a female to pair up.
One other thing that some birds can convey with their song is their age and experience. Some birds (like flycatchers) have songs that are pretty much hardwired and show little variation. Many others, though, continue to build upon their learned songs throughout life. Younger birds have a more straighforward song, hewing pretty close to a "template" that they learned as a juvenile. As time goes on, they elaborate on the theme adding little trills and flourishes and making the song completely their own. This type of complexity lets a female know that he's been around for a few years and probably has a good idea of how to raise a family successfully.
One other interesting thing that's been shown is that some species of birds (chickadees, for example) actually have song centers in their brains that grow during the breeding season and shrink back during other times of the year. Talk about efficient use of resources.
On another note, as is true with real estate, in birding it's all about location, location, location - 1,000+ British twitchers turn up for a White-crowned Sparrow.
(American Robin photo source and permission.)
