Ten miles north of Atlantic City, New Jersey, is the Edwin B. Forsythe National Wildlife Refuge where I spent a morning photographing herons, terns, geese, ibis and this snowy egret. He got me to thinking why I see so many birds standing on one leg.
A Google search revealed this explanation:
Birds’ legs have an adaptation called “rete mirabile” that minimizes heat loss. The arteries that transport warm blood into the legs lie in contact with the veins that return colder blood to the bird’s heart. The arteries warm the veins. By standing on one leg, a bird reduces by half the amount of heat lost through unfeathered limbs.
I’ve since found out another reason for why a wading bird, like this egret, will stand on one leg since I posted on Monday:
Birds also purposely create their own shadows in the water. Apparently egrets can blend better with their surroundings and look like a shrub to a fish by standing on one leg. The word “pedigree,” which is one’s family tree, comes from the French “pied de grue” – crane’s foot. This is sometimes represented artistically as a tree with exposed surface roots or even a bird’s foot in old ancestral diagrams. Take a close look at the egret’s legs and feet if you ever get the chance. The tough skin really does make them look like tree trunks, and undoubtedly fools fishes seeking a bit of shade for cover too.
Don’t you feel smarter now?