River of Birds
roughly a billion birds migrate northward across the Gulf of Mexico,
en route to breeding habitats from their wintering quarters in the
tropics. Imagine being a bird, flying over hundreds of miles of water,
without food or any place to rest. And imagine being there to watch
as thousands and thousands of migrating birds fly over your head! People
working on oil platforms on the Gulf of Mexico don't have to imagine
it. They've had the experience!
John Arvin Describes A River of Birds
From an offshore platform about 80 feet above the Gulf of Mexico, naturalist
John Arvin watched the passage of thousands upon thousands of songbirds one
spring night. These excerpts are from his writings at dawn, after a whole
night of watching the river of birds flooding toward shore:
"Wednesday, April 29. Up nearly all night marveling. The river of birds
continued unabated, ranging from 30-50 birds passing my position per second in
the illuminated air space I could see. (That extends maybe 100 meters out from
the platform from within a few feet of the water up to about 200 meters.)
"By 05:00 the rate had fallen off to about 10-15 birds per second. On my
05:00 round I found the well bay full of birds (at least 50 individuals). I could
see many tails of sleeping birds sticking out from the beams of the ceilings.
Several Blackpoll Warblers were hopping around on the decks foraging under the
lights well before it began to get daylight.
"It is now just daylight and the flow seems to have stopped or to have gained
enough altitude that I can no longer see them with the unaided eye. However,
there are birds flying around the platform in random directions that had evidently
put down during the night and now are being stirred up by human activity.
"This has been the ornithological spectacle of my entire life. Intellectually
I knew this sort of thing had to happen, at least occasionally, but to actually
stand in one place for hour after hour and watch a steady flow pass just a few
feet from you is like watching a major river. I'm a little rocky from no sleep
but I have never been remotely struck by any other ornithological event like
I have been by this. I suspect that very few people on this planet have seen
what I have seen in the last 12 hours. It is a spellbinding feeling I will carry
to my grave."
If thousands or millions of other birds migrate over the Gulf on a single dark
night, how do they keep from bumping into each other? Unlike cars, birds don't
have headlights, but they can do something similar to what car drivers do to
help other drivers notice them. In the way that car drivers use horns, birds
make little calls as they move. Fortunately, birds have such good hearing that
they don't need to be as loud as car horns! But the tiny sounds made by migrants
can be heard hundreds of feet away on the ground.
This! Journaling Question
When migration starts in your area, choose a nice night when birds might be
migrating. Stand out in your backyard after dark. Listen! Do you hear any migrating
birds? Can you count them per second, as John Arvin did? Describe what you
heard and how you felt.