For the Birds Radio Program: Spring Migratory Flocks
How do birds negotiate flying through strange lands during migration? Chickadees are a big help!
For the next three months, birds will be passing through the northland from farther south, headed farther north. Tens of thousands of them will hang around for a few days, strangers in a strange land, before moving on. They won’t have a clue where hawks hunt day after day, where people let their cats out, where the juiciest bugs or the best water sources are.
The act of traveling during migration is hazardous enough, but all the stops in between, critical for fueling up as well as resting, are probably even more dangerous. Fortunately, some of our local birds act as a welcoming committee for the transients. Black-capped Chickadees, the original Norwegian bachelor farmers, may not actually rub shoulders with other birds, but they do enjoy hanging out with friends and strangers both, just so long as everyone respects their personal body space. Chickadees have a varied diet, taking seeds and insects, and they are curious and intelligent. So chickadees are likely to know where good food supplies are, and they are also likely to notice predators and other dangers and give the heads up to warblers, vireos, and other birds who hang out with them. Chickadees are found just about everywhere, and they call often, making them easy for strangers to find. So as little birds pass through, they very often join chickadee flocks. Interestingly, as many warblers start singing, they become stressed out when they’re too close to others of their own species, but they feel comfortable near other species. So in May, a single chickadee flock may associate with a dozen warblers representing eight or even ten different species. Of course, this early in the season warblers haven’t arrived in north country, but the first kinglets and brown creepers will almost all be found with chickadees.
Migrants passing through need plenty of food to fuel the rest of their journeys. By May when the huge bulk of neotropical migrants come, trees will be leafing out and there will be plenty of bugs. But right now the seeds and fruits produced last year are pretty depleted, and it’s still too early for new supplies. What are birds eating during these last days of winter, and the earliest days of spring? Yellow-bellied Sapsuckers look especially for aspen trees, which are easy to tap for sap. The first migrants, especially kinglets, Yellow-rumped and Cape May Warblers, phoebes, and Ruby-throated Hummingbirds, look for sapsuckers and their drill holes. Sapsuckers often move between two or three different trees, so when they’re at one, littler birds visit the others to take running sap and the insects drawn to it. Cape May Warblers are especially aggressive at taking over sapsucker drill holes. During one cold snap in early May, I once watched a Cape May defend an appropriated feeding spot against every competitor, including the much larger sapsucker who made the holes in the first place.
On the coldest days, early migrants, especially those who eat a lot of insects, will have some trouble finding food. Insect-eating birds don’t normally come to feeders, but a few notice that the chickadees they’re with do, and sometimes they investigate. I’ve had several species of warblers land on my feeders over the years. One spring a Yellow-rumped Warbler spent a few weeks feeding on little chips of suet that fell onto my sunflower seed feeder from the suet feeder above it. Now that I’m putting out mealworms for my chickadees, I suspect that a few more warblers will discover and take advantage. But since coming to a feeder, away from the sheltering branches of trees, is not a natural warbler behavior, I’m not sure they’ll discover the mealworm dish. Only time will tell.
As wonderful as chickadees are in the dead of winter, when we’re hungry for their warmth and good cheer, they’re even more wonderful in spring, as they befriend so many lovely birds from faraway lands, giving them a better chance at survival. In the long run, most songbirds form lovely unions, insuring domestic tranquility, providing for the common defense, promoting the general welfare, and securing the blessings of liberty to themselves and their posterity in a manner that is very much in keeping with the spirit of the Constitution of the United States and the ideals of the United Nations. People could learn from their example.