Meteorologists used to puzzle when, on certain fall nights, radar indicated vast storms rising out of nowhere — storms that didn’t exist. If you got under one, climbed up on a roof, and looked, you wouldn’t see or hear anything except the clear autumn stars, and sometimes, the faint chirps of sparrows and warblers and thrushes from hundreds of feet up in the night sky.
It turns out when the weather is just right, millions of songbirds rise into the night sky at once, taking advantage of a single perfect fall night to power hundreds of miles south — and they show up on the radar like an approaching storm.
Now, ornithologists use radar to track migrating birds on their flight south.
The Portland Bird Alliance tracks these events on social media, releasing “Lights out” advisories when storms of birds approach. On Sept. 16 of this year, for instance, more than 4 million birds were expected to fly over the Northwest — many of which could die, or become confused, in too-bright city lights.
Even at night, songbirds rely on subtle lights to navigate — the light of the stars, the moon, the red light of dusk that, shining in their eyes, triggers chromatoid pigments, enabling them to see the earth’s magnetic field directly.
Human lights are not subtle.
They dominate the natural lights birds need. And a bird’s instincts, oriented to the little lights of nature, drags it toward towns and lighted windows like a moth to a flame.
Even the 9/11 memorial lights in New York City have been turned off at times, to avoid trapping the hundreds of tiny, confused songsters in their beams and exhausting them.
Robbed of their energy, or broken against a bright window, the birds are less likely to survive the long migration to Mexico, South America, or wherever they spend the winter.
Turning off outdoor lights and covering windows helps them. And it doesn’t cost us much, except perhaps our comfort, for just a few nights per year.
I like to turn out the lights, then climb on the roof and listen — sometimes, if I’m lucky, I hear a chip, a whisper, a few contact calls, a tiny sound of migrants streaking overhead, safe in the darkness.
Commented