Wednesday, January 02, 2008

Sensitive to the Chilly

This is a really old image but I feel for this timid bird in weather like this. Do birds' feet get cold in icy water? Should we be dressing our winter waterfowl in webbed booties? Luckily both this duck (?) and I wear scarves. And I don't have to swim to work.


Anonymous said...

Umm, I don't know if you're actually interested in this or not, but it's really quite a fascinating topic!!! The feet of most waterfowl actually have a unique system of circulation so that their feet don't get cold! Or rather, their feet get cold, but they don't care:

"The legs and feet of waterfowl also play an important role in maintaining body temperature. Ever wonder how a mallard can stand comfortably on ice? A unique heat-exchange system in the birds’ legs known as counter-current circulation makes this possible. The large, flat feet of waterfowl are natural radiators, so to minimize heat loss, the arteries and veins in the birds’ legs work in tandem to retain heat. Arteries supplying blood to the feet pass alongside the veins removing blood. The warm arterial blood flowing to the feet is cooled by venous blood flowing back to the body where it is warmed again. Consequently, very little of a duck’s body heat is lost through its extremities. Thus, while the core body temperature of a duck standing on ice is near 100 degrees Fahrenheit, the temperature of the bird’s feet may be just above freezing.

To further conserve heat in cold weather, waterfowl reduce the volume of blood flowing to their feet by constricting blood vessels in their legs. Experiments have shown that waterfowl gradually reduce blood flow to their feet as the air temperature drops to 32 degrees Fahrenheit (the freezing point). When temperatures fall below freezing, however, waterfowl again increase blood flow to their feet to prevent tissue damage. The birds also protect their feet by drawing them into their flank feathers and close to their body. To further minimize exposure in bitter cold weather, waterfowl often stand on one leg at time, tucking the other leg into their body feathers to protect it from the elements." -- from the "Understanding Waterfowl" page of Ducks Unlimited

It goes on! You can read more on the above page and there's a ton of stuff about it on the web. Quite interesting!

Anonymous said...

Crap, the link did not work right. Maybe if I make a hyperlink it will work. Try this.