Sunday, March 8, 2009

Indicator Species

Most of you know what an indicator species is. If you don't, its an organism that can be used to gauge the health of an ecosystem. Amphibians are often used as their health can give scientists an idea of how the other species in an area are faring.

I have my own. Ospreys are an indicator of the beginning and the ending of my falconry season. If you have never seen one, They are described as;

The Osprey is a fish eating hawk (also known as a buteo) about 24 inches tall with approximately a 6 foot wingspan. It's about the size of a small Bald Eagle, the Osprey's fishing competitor. People tend to confuse the two, but the gull-like crook in the wing, the dark brown line through the eye and on the side of the face of the osprey are good hints for identification.

They leave our area in mid October and you will not see them until the very beginning of March. When the Osprey leave, I know that it is time to start getting my own hawk
s in shape for hunting.

Where the osprey go, I was never sure. It turns out that they, like most migrating raptors, head for South America. But what is really cool is that University
of North Carolina has begun tracking all of the movements of the osprey. They then can track them with GPS all over the globe. Check out the maps here.

Well. My osprey are back.
They frequently fly over our backyard, fish clutched in their talons. There are nesting pairs all over, which is a blessing, as it wasn't that long ago that they were threatened with extinction.

Once the Osprey were threatened with extinction because of the wide-spread use of pesticides like DDT. With its long term and accumulative effects this pesticide was particularly devastating on the egg shells of this and other birds high up in the food chain. But with the ban of DDT at least in North America the population is recovering, especially where aided with nesting structure provisions and good fishing habitat.
They are fairly common here now and today, two of them sat in a nest over a nearby canal.

One took off and flew low lazy circles over the water, calling to her mate.

In response, he launched from the nest and landed directly over my head in a loblolly pine.

He called back to her until she faded out of sight, only to return later. Then they circled each other over head until they disappeared over the treetops.

Spring is here.

No comments: