Friday, May 6, 2011

Ospreys and Man

We saw another osprey nest yesterday at Fort DeSoto Park, this time on a relatively deserted beach. The ospreys were nesting on an open manmade platform within a few yards of the Gulf of Mexico. The mother was on the nest with chicks that appeared half grown. She shrieked at me when I got close to take photos, but then ignored me. It was comforting to see these majestic birds raising their young in such an exposed location, seemingly without much fear of humans. 

Ospreys nest with chicks
Ospreys became endangered in the 1950s and 60s after the mosquito-killer DDT worked its way into the food chain. Ospreys, which almost exclusively eat fish, absorbed toxic amounts of the chemical, which resulted in thinning of eggshells. In some countries, such as Scotland, ospreys also were harassed by egg collectors, resulting in diminished populations.

Ospreys nest on a manmade platform adjacent to the Gulf of Mexico
But today the osprey is no longer endangered. Ospreys got a second chance when DDT was banned after Rachel Carson's publication of "Silent Spring," which documented the devastating effect the insecticide was having on birds. We see (and hear) them regularly both on the Gulf Coast of Florida and on the coast of Maine. Several times this vacation we've seen one fly past our building, claws outstretched and carrying a fish, presumably to feed youngsters. I have also seen one perched on a channel marker, leisurely eating a fish.

Ospreys need appropriate nesting sites to reproduce. They favor tall structures near water for their large nests of sticks. Manmade platforms specially built to attract ospreys have helped them make a comeback. But the birds also make creative use of other platforms, as you can see in the photo below, taken in Maine last fall.

Ospreys' nest on an old fishing boat, Chebeague Island, Maine
I am heartened to witness ospreys and humans coexisting peacefully. It's a success story I hope will be reproduced often.

For more information on ospreys:
Osprey World
Birds of North America - Osprey

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