As a gull, my home-area is mostly out around Far Rockaway or Roosevelt Island but I do get into Prospect Park often enough, to check out the Brooklyn bird eatery niches, and to see my friends and share my knowledge. I was there recently, on a surprisingly cold morning. It was that first chilly day in the Fall, you know, when your mind first turns to wintery things. The night before I had heard the first announcing sound of that season, our cousins, the migrators, flying south and honking, hinking and cackling.
Over the years I’ve watched the planes at JFK in winter getting de-iced before they fly. The workers spray some kind of chemical on the planes. For planes, ice can build up on the wings as they fly through cold winter rain or clouds and that ice can stop a plane from flying safely because it changes the curved shape on the top of the wing and the plane loses its lift. As I listened to the birds overhead, I started wondering if our migratory cousins have the same icing problem when they fly through winter rain.
Turns out that doesn’t happen with birds, mostly because of all that preening we do with our beaks on our new-season feathers, which puts a layer of ‘preen-oil’ on our feathers. Preen oil is different for different bird species, but is a natural waxy, oily residue in our mouths that sticks to our wings, making them become hydrophobic surfaces. That means, like water poured onto oil, the water beads-up and runs right off it. So raindrops cannot sit on our wings and freeze. Brilliant! I will be thinking about that this winter as I watch the planes getting de-iced, and also when our migrating cousins are flying overhead.