I can’t help it. At this time of year, I’m obsessed with bird migration. I talk about it with everyone—even complete strangers. Often I hear responses like this: “Well, I’d like to see migrating birds sometime. But I don’t live on a flyway.”
Here’s the good news: We all live on a flyway. It’s true that some birds, such as geese and cranes, follow fairly narrow corridors of travel, and shorebirds will gather only at certain spots. But right now, in early May, hundreds of millions of small songbirds are migrating north, and they pass over every square mile of land and water in the temperate regions of North America. In fact, during their travels, a few of them will stop in just about every tree on this continent. So no matter where you are, you have a chance to see some migrating songbirds.
The nature of their travel
The stars of the show right now are small birds that travel large distances: songbirds that spend the winter in the tropics, coming north to spend the summer in the United States and Canada. These birds—dozens of species of warblers, thrushes, vireos, orioles, flycatchers, tanagers, grosbeaks, and more—migrate mostly at night. They take off just after dark, fly through the night, and land near dawn, if they’re over land at that point (if they’re over water, of course, they keep going). They may cover 200 miles or more during a night flight, and when they come down, they need to rest and feed and build up their strength for the next flight.
These birds have amazing navigational powers. A blackburnian warbler, for example, might fly from Maine to Ecuador in the fall, coming back in spring to the very same tree in Maine where it sang the year before. But during their night flights they are subject to wind and weather, so in the morning they might come down practically anywhere. If they still have energy left, they may fly several miles after sunrise, looking for a choice patch of woods or marsh or meadow. But eventually, each bird will settle for whatever spot it can find, and that spot will have to serve as its stopover habitat.
Where to look for migrants
The short answer is that you can look for them almost anywhere. Most of the migratory songbirds live in trees and shrubs, so they’ll settle for even one tree or one shrub, at least temporarily, if they have no other choice. (I once saw an ovenbird and two American redstarts in the shrubbery of a small planter at a bank building in downtown Philadelphia.) Small city parks often host a fine assortment of migratory songbirds; the surrounding square miles of concrete serve to concentrate the birds, as the tired migrants gravitate toward the small patches of green. Isolated trees in city backyards or hotel courtyards may act as stopover habitat for small birds that are just passing through.
Very large patches of habitat, such as large parks or forest areas, can be better for the birds but more challenging for the birders, as the migrants become harder to find in those surroundings. Songbirds in stopover habitat often gather in mixed flocks, so if you’re not seeing any birds, keep moving until you find a migrant—then look around to see if it has company.
When to look for migrants
Because these birds travel at night, early morning is the time when they’re most likely to be seen in marginal habitats. By later in the day, they may have moved on to look for another spot with taller trees or thicker thickets. If you have a backyard or a nearby park with only a few trees, try to check them first thing in the morning to see if any new visitors have arrived overnight.
Some nights produce much heavier bird traffic than others. Watch the weather to look for good flight nights. The ideal night in spring will be when areas just to the south of you have clear skies, warm temperatures, and steady winds out of the south. If storms move in during the latter part of the night, the rain will cause birds to come down wherever they happen to be at that point. A damp morning after overnight showers can produce a bonanza of new migrants in your local trees.
Be alert to the possibilities
Most people don’t see migrant birds because they don’t look for them. You can increase your chances simply by being aware of the possibilities. Get a bird checklist from your local Audubon chapter, borrow a basic field guide from the library, and try to get a general idea of the groups of migratory birds.
And above all, just take a second look at any bird that you notice. That brown bird under the hedge might not be one of the local city sparrows—it might be a Swainson’s thrush, just arrived from Panama. That yellowish bird in the tree might not be a local goldfinch—it might be a Cape May warbler that has just flown in from Jamaica. At this time of year, migratory songbirds are everywhere, pausing for a moment in practically every tree. Just by paying attention, you may get to make the acquaintance of some amazing world travelers.