For the Birds Radio Program: Human and Avian Migrations
How would a human car trip to Chicago or bike ride around Lake Superior compare to bird migration?
Now that many birds are getting ready for and beginning their seasonal migration, I found myself making my own migration south to Chicago this week. Human migration is both simpler and more complex than bird migration. Birds get far better mileage than we do, even using the most fuel-efficient cars. I like to drive at or a bit below the speed limit, so my little Ford Aspire gets over 40 miles per gallon, but birds go thousands of miles per gallon of fuel, and don’t waste fossil fuels or other non-renewable energy resources at all.
My little car has covered almost 160,000 miles in the 9 years I’ve had it. But Barn Swallows, just in the course of their day-to-day lives zipping about catching insects cover that distance in less than a year. The oldest banded Barn Swallow known to science lived to be 8 years and 1 month—during that time this bird that weighs less than an ounce probably flew one and three quarters MILLION miles—10 times what my car has done.
If birds expend far less energy to cover far more miles than us humans, we have some advantages over them. We can stay dry and comfortable no matter what is happening around us. Most weather situations don’t even slow us down. And when we’re in trouble on a trip, we have a far better support system. I needed a parking spot when I was visiting my aunt in Chicago, and after driving through all the neighborhood streets several times and giving up, I pulled into the no-parking circle drive outside her high rise building just as a car pulled out of a space across the street. Instantly, a motorcycle pulled in, so I called to him asking if there was room for my car, too. He said yes, and he’d hold it for me as I backed out of the circle to pull into it. I’m not used to parallel parking in a busy city, so he even guided me into the space. Of course, birds don’t need parking spaces, so we hardly have the advantage as far as that goes. But we humans also help one another when we are in trouble. When I was leaving Chicago a few days later, my car broke down. Within just two or three minutes after the car quit in the middle of a busy intersection, two women pushed me to a safe parking spot. I used my cell phone to call my trusted mechanics at home in Duluth, and then called AAA. Within 10 minutes a tow truck was taking my car to a repair shop, and within a few hours I was back on the road, good as new.
When birds are in trouble, their flock mates may also take notice. When a Sharp-shinned Hawk attacks a Blue Jay, other jays instantly start squawking and even dive-bombing the predator. But if a jay gets injured, there’s no way other jays can help it take wing again. There are records of jays providing food for injured flock mates, and I’ve read of one case of jays helping an old, partially blind jay to water, but they can’t give it a tow. And despite my mode of transportation breaking down, I had alternatives. When a bird’s wing is injured, it has no options.
Birds can just pick up and fly, their directions and compass embedded into their brains before they’re even hatched. In 1962, scientists captured and banded 574 White-crowned Sparrows near San Jose, California, and shipped them to the Patuxent Wildlife Research Center in Maryland just to see if they could find their way back. No one knows for sure how many found their way back, but the following autumn 8 of them were recaptured in San Jose. Of course, if we lack orientation and navigation hardware in our brains, we can use maps and GPS systems, or, if we’re not hampered by gender issues, we can even ask someone else for directions.
Our human migrations aren’t as seasonal, or for the same purposes, as bird migration. I headed south on Saturday, and by Wednesday was on my way north again. Now I’m watching my daughter prepare for her own migration—Saturday she’s going to start a bike trip around Lake Superior with a couple of friends. Birds don’t make long trips just to visit family, and certainly don’t fly in circles just to say they’ve done it. They do things their way, and we do them ours. And all I can say is Vive le difference!