Over the last few weeks, the number of Sandhills around White River has dwindled from the hundreds that once gathered in harvested cornfields, to only a few. Instead of an orchestra creating the soundtrack for the glory of sunrises, now we only hear the occasional duet.
If you are one of those too-few people who stop mid-stride to listen to the call of birds, you may periodically look up. And there in the clear blue, way up high, a sound too sonorous for those tiny specks in the sky. Migrating Sandhills, directed south by an unknown guidance system and driven by instincts we don’t understand.
The unusually warm fall here in central Wisconsin seems to confound the reports of early avian arrivals in wildlife areas farther south. For three weeks, the weather here has been like an extended Indian summer; T-shirts and mosquitoes in late October? as rare as Whooping cranes…
It’s also been wet here with lots of standing corn still too moist to harvest. It seems like mid-September but that’s from a human perspective. We spend nights in a heated trailer, dry and comfortable, not standing hock-deep in cold water. In the early mornings, we watch them from warm trucks while sipping coffee, not poking through the frost for bits of food freckled on the ground.
Despite the advancement of science, the exact techniques birds use to navigate during migration are still largely speculation. We know that some can interpret celestial patterns and others sense magnetic fields, but exactly how cranes find their way from northern Canada to the gulf coast of the United States is still a mystery. Even when shown the way by parents or aircraft, the return trip a few months later would be difficult.
Our studies have demonstrated that landmarks might help them home in on nesting grounds once they get close, but not over the course of 1200 miles from Florida to Wisconsin. If you have ever navigated a small aircraft without the aid of a map or a compass and wandered outside your home range, you will understand how getting lost is almost unavoidable.
We don’t know how they find their way and it appears we also don’t know what convinces them that it’s time. The longer we work with Whooping cranes — seems the less we know. We have been migrating with birds almost every year since we began leading them south in 1993. Despite the clocks, the calendars and the warm trailers, it feels to me like it’s time to go.
Maybe that’s all there is to it – just a feeling.