For the Birds Radio Program: Fall Migration Report
Recast from September 14, 1988.
The skies of autumn are pulsing with the wingbeats of migrating birds, coursing through their arterial flyways like the blood of life. There is such mystery to migration–and such miracle. Imagine a fragile hummingbird rushing along, stopping for a snack whenever it spots a patch of jewelweed or a promising feeder, but then pressing on again, its heart throbbing 650 times every minute, its wings beating over 70 times every second. It travels over a thousand miles down to South Texas, which is amazing enough without even considering that once it arrives there it has to fly 600 miles non stop over the Gulf of Mexico to Central America without refueling. Its heart beats at least 936,000 times during that journey over treacherous water, while its wings beat at least 6,048,000 times without a rest. And all this at the peak of the hurricane season. That kind of feat makes our puny human marathons, and even ultra marathons, look like pretty tame accomplishments in comparison.
Although some people believe that hummingbirds will stay north if feeders are left out after Labor Day, they’re wrong. By now, most of the adult male hummingbirds are gone from the Northland, in spite of the abundance of flowers and feeders. In two or three weeks, the adult females will all be gone too. And the young will leave as soon as they have enough fat to fuel their flight; if you close up shop before they’re ready to go, especially after a frost kills the nectar-producing flowers, you may well be dooming your neighborhood’s young hummingbirds, and any migrants from Canada who need to refuel. It’s perfectly okay to keep out hummingbird feeders as long into fall as you have any takers–after all, laziness is a human characteristic, not an avian one. You could mail 10 hummingbirds to Mexico with a single stamp, but not only don’t they want our help, they make it across borders much more efficiently and quickly on their own power.
In fall, migrating birds often head south on weather systems. In most areas a cold front will bring in migrants in good numbers. If you have a chance to visit Hawk Ridge in Duluth this fall, your best bet is a day when the wind is from the northwest. Hardly any hawks fly on an easterly wind, but if you find yourself in town on one of those cold, wet east wind days, check out the warblers and shorebirds in the harbor, at Park Point, and along the shore. The worst days for migration are the calm, pleasant days when the wind is from the south–those junky nice days are the ones birders sleep in.
September is the peak month for most migrating birds in the Northland. Kestrels and Sharp-shinned Hawks start flying in August, but Broad-winged Hawks begin the first week of September swirling in flocks called kettles. Hawk Ridge is famous for its broad-wing migration, but actually alert people can find kettles just about anywhere when the weather’s right. Back when I taught junior high in Madison, Wisconsin, a good kettle flying outside my classroom was cause enough to cancel one math test. In the overall scheme of the universe, migration is far more interesting and enriching than junior high math, and that’s the truth.