Thursday, December 3, 2009
Great Blue Herons - Adapting For Survival
Ask any child why birds fly south for the winter and if it's not answered with the old joke, "It's too far to walk!" followed by a chorus of giggles, the likely second choice - favored by many adults as well - is that it's too cold. Look at your bird feeder as flurries fall and you know in a flap of a feather that answer doesn't hold true. Birds are generally well insulated with under layers of downy feathers and moisture shielding flight feathers. But when the food source is gone the birds must depart too. Hummingbirds seek out nectar, swallows consume mosquitoes and vultures want fresh – unfrozen - carrion. Those bird species and many others departed a month ago. The seed eaters (chickadees, sparrows) and meat hunters (owls, woodpeckers) tend to stay put. And that brings us to the great blue heron. These colony nesting majestic slate-gray wading birds with six-foot wing spans, hunters of fish and frogs, should have departed to warmer waters. Most did. But not all. Great blue are highly adaptable and more than a few stay in northern climates all winter, finding waters that don't freeze and/or switching to a diet of small land mammals such as voles. On a recent excursion to the Drayton Plains Nature Center I came upon a solitary great blue heron as still as a statue at the edge of a slowly flowing channel of the Clinton River. With its reflection shimmering in the chilly waters it waited for movement of a small fish. And if a fresh fish fillet did not come to be, a patient stalk on shore for a meaty meadow vole was most likely in store With fingers numbing I snapped a few pictures and left this prehistoric looking bird to perfect its adapting for survival techniques. For me: home to hot coffee. My way of adapting to a chilly morning with winter at the door.