Friday, October 14, 2011

Its Avian Friday: Gavia immer


(Picture used http://www.alaska-in-pictures.com/gavia-immer-4841-pictures.htm)

Now that I live in the great North, and near the ocean, the Common Loon (Gavia immer) is a great deal more common to me. Of course on can see them on any body of water across the US, I see them more now that I did when my excursions into the field were in the Mid-West. It is one of the more evocative and elegant birds to be found in the US. Its haunting call in the evening can make any person's day (birder or not). It seems to encapsulate everything that humans find appealing about the wilderness.

The evolution of loons (Family Gaviidae) has resulted in a group of birds that are more at home in the water than they are either in the air, or on land. Their flight always appears somewhat labored, and on land they can have a great deal of trouble walking. The aspects of their anatomy that make them ooze through the water at great speed, that make them hydrodynamic I suppose, do not make them equally aerodynamic. Increased optimal design for life in the water means trade-offs in other areas. Their feet set back at the end of their heavy tube like bodies, mean great propulsion through water, but make walking on land difficult to say the very least. The costs of these trade-offs must be minimal, which is another way of saying the benefits of life spent almost entirely on the water outweigh the costs of not being able to move well on land, or as effectively through the air.

Right now the The Common Loon is not in its breeding plummage, but they are still elegant. And one can see them with ease at numerous sites around Casco Bay. A good pair of binoculars and they can be seen regularly around Mackworth Island.