Wednesday, March 7, 2012

Osprey

Ospreys are magnificent raptors. They dive feet first into the water, 99% of their prey consists of fish. As spectacular as their dives are, they only reach depths of about a meter. Thus they take only fish from the shallows or surface. Other prey items have been reported for Ospreys (birds, snakes, voles, squirrels, muskrats, salamanders, and even a small alligator (Pool et al. 2002)) and I once saw one carrying a small mouse over a forest clearing.

Ospreys breeding in Minnesota winter in Central and South American. Poole et al. (2002) calculate an osprey may "fly more than 200,000 kilometers in migration during its 15-to 20-year lifetime." From the 1950s to 1970s, Osprey populations crashed primarily due to pesticide poisoning. Their numbers have rebounded due to pesticide control and an aggressive program of providing Ospreys with artificial nest sites. In some areas, perhaps due to the cutting of old trees, almost all Ospreys use these sites.

I took these photographs a couple of winters ago in southwest Florida. These birds, as many across North America, are tolerant of humans and sometimes allow close approach.


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