Tuesday, June 12, 2012

Retired Birds


I have always been fascinated by migration. I have a map of bird migration hanging on the wall of my office. I read everything I can about it, and I marvel at the mysteries that science has unraveled about how birds and fish navigate over literally thousands of miles of ocean.

Here in the South Carolina Low Country, we know a lot about migration. Over the past few months, we have witnessed the streams of warblers passing through as they migrate toward nesting grounds full of food and safety further north. The red knots recently stopped on our beaches to feast on horseshoe crab eggs before continuing their 16,000 mile journey from Tierra del Fuego to the Arctic tundra.

Black-bellied Whistling Ducks
We are seeing some unusual migrants this year, too, as birds may be expanding their ranges in response to climate change. Several families of black-bellied whistling ducks seem to have settled in the Savannah Wildlife Refuge. And roseate spoonbills, while never total strangers to the area, seem to be more widespread than usual this year.

All this migratory activity, even when it is outside normal ranges, tends to satisfy the crucial need for organisms to reproduce and perpetuate themselves. But when I study the fantastic migrations of some bird species in particular, I can't help but wonder if there is some additional evolutionary force at work, a force that favors exploration as well as migration. Albatrosses, for example, cover thousands of miles of open ocean just to find food to feed their nest-bound chicks. Arctic terns fly north along the entire coast of South America and North America in spring to nest near Greenland in summer, then return south in fall via Europe and Africa.

For the past few winters a pair of highly endangered whooping cranes has been sojourning in the vast marshes of the ACE Basin estuary in South Carolina. What's unusual about these birds is that they apparently belong to a flock of hatchery-raised whoopers that scientists are training to migrate between Wisconsin and Florida. The only natural whooping crane flock, numbering less than 300 birds, travels between the Texas coast and northern Canada and has been doing so for hundreds of years.

Lowcountry Whooping Crane
The hatchery-raised flock, though, is showing some signs of independence. They have been training to migrate by following ultralight aircraft between their summer and winter grounds. Last year the whole lot of them refused to continue on to Florida after being grounded on the Alabama coast for several days by a storm.

Several years before that, two birds broke off from the main flock and diverted to South Carolina to spend the winter. They apparently go back to Wisconsin in summer with the rest of the flock, but they have decided they prefer winter in the Lowcountry rather than the Sunshine State.

I love that South Carolina pair, and not just because they choose to spend the winter in South Carolina. I love their independence, the fact that they chose a different direction. They are pioneers, and if they successfully nest and their babies follow them to the Lowcountry, they will be the reason this "artificial" flock succeeds, by expanding territory and improving the species' chances for survival.

Call them independent, call them pioneers, these birds are important, just as the whistling ducks that showed up in numbers this year, and the expanding numbers of spoonbills. I'm assuming, of course, that these are breeding birds that will raise young and eventually declare the Lowcountry home.

But could some of them be retired birds, the ones who aren't breeding any more, whose chicks have all fledged, but who still have plenty of life and perfectly good wing feathers? After all those seasons of flying over seas and coasts and mountains, stopping over in marshes and ponds and rivers, in short, after seeing some of the most beautiful parts of this big blue planet, do they just pick out a pothole or swamp and hunker down and wait to die? I think not!

Snow Geese
Hey, that's what wings are for, and I think they're using them. They've done their bit to keep the species going. Now it's their turn to travel for fun and explore new places. It's what they've been working for all their lives, all those months on the nest, regurgitating half-digested worms and fish for their squawking babies, building and rebuilding nests that just get fouled with baby bird poop, teaching the babies to hunt or forage, maybe even mourning the ones that don't make it.

All right, this is totally unscientific. I'm projecting. It's what I would do if I were a bird, because it's what I'm doing as a "retired" human. As long as the wings still work and the wind blows, I'm gonna fly, to new places and old, just because they are there. And I'll tip my hat to the birds that join me.