Ospreys in Ohio
Ohio’s osprey reintroduction program is a huge success. Originally started in 1996, the program had a goal of 20 nesting pairs of ospreys by 2010. That goal was achieved in 2003 – 7 years ahead of schedule. Since the summer of 1996, 282 young ospreys (also known as fish eagles or fish hawks) have been placed in hack boxes at six locations around Ohio in an attempt to reintroduce the bird to the Buckeye State. Due to the success of the reintroduction program, ospreys are no longer released, but Division personnel still monitor the number of nests and chicks.
The young ospreys were donated to the Ohio project by New York, Virginia, and Maryland, states that already have established osprey populations. One unique aspect of Ohio’s program was the cooperation between the Division, Langley Air Force Base in Virginia, and USDA Wildlife Services stationed at Langley. There are over 20 osprey nests at Langley, thus the potential for collisions between jets and ospreys (especially newly fledged osprey) is high. To lower the possibility of collisions, Wildlife Services personnel remove chicks from the nests before they fledge and donate them to states such as Ohio which are reintroducing them.
Other project costs are funded by donations, tax checkoff and the purchase of wildlife conservation plates. The sites chosen for the releases were Deer Creek Wildlife Area in central Ohio, Lake La Su An Wildlife Area in northwest Ohio, Portage Lakes in northeast Ohio, Salt Fork Wildlife Area in southeast Ohio, Spring Valley Wildlife Area in southwest Ohio, and The Wilds also in southeast Ohio. Each hack box location was selected based on three criteria: 1) appropriate osprey habitat and an adequate food supply of fish, 2) proximity to a wildlife area work unit so that the young birds could be easily monitored by biologists, and 3) not within an active bald eagle territory, a bird that could be a competitor with ospreys.
Ospreys were once a common sight throughout North America, but habitat destruction, persecution and the wide-spread use of chemical pesticides such as DDT during the middle of the twentieth century led to a drastic population decline. In Ohio, the last successful osprey nest was recorded at Grand Lake St. Mary's in western Ohio in 1913. Unsuccessful nesting attempts were made by pairs of birds as late as the 1940s at Burr Oak Lake in southeast Ohio and Buckeye Lake in the central part of the state.
And ospreys are spectacular birds to watch, particularly when they are feeding. Hovering high above a lake, river, or pond, these large white and dark-brown birds search for fish cruising near the surface. Spotting one, they quickly fold their wings and dive, hitting the water talons first. Ospreys are the only species of bird that combines this plunge-diving feeding behavior with a raptorial foot--a foot with a flexible toe that can be moved to grip a slippery fish with two toes pointing forward and two back. The bottoms of an osprey's feet are also specially adapted for gripping and carrying fish, as they are covered with short, sharp spines. Once airborne again, the bird manipulates the struggling fish so as to carry it head first, making it more streamlined in flight. The osprey also removes any water from its feathers as it flies by shaking itself, much like a dog.
The young ospreys (four to six weeks old) were placed in the hacking towers in late June/early July and were fed a diet of fresh and frozen fish, mainly suckers, carp, and catfish. The food was lifted into the towers via a long pole with a basket on the end. And although ospreys will not imprint on people, human contact was minimized as much as possible. The birds remained in the barred hack boxes for two to three weeks before the doors were opened and they were free to come and go, but fish continued to be provided until the young ospreys learned to successfully hunt on their own.
The first-year survival rate for the hacked ospreys is expected to be about 40 to 50 percent. Those that do survive will migrate south, some as far as Central and South America. They are expected to return to Ohio in three to four years as breeding adults. Once mated, the pair will build a stick nest lined with grasses either over or near water. Also, the Division of Wildlife will be helping the birds as much as possible by constructing nesting platforms in suitable, secure osprey habitat.
Ospreys use the same nest year after year, which sometimes grows to be as much as five feet wide and several feet deep. Ideal nest locations consist of an open, high platform near a good supply of fish. An open approach to the nest is essential, especially for a bird with a four-and-one-half foot wingspan.
Usually three or four eggs are laid by ospreys and both parents help with the chore of incubation. The eggs are white with brown splotches and about the size of a large domestic hen's egg. They begin hatching in about 38 days, usually in the order they were laid. This means that the last young to hatch are smaller and several days behind their siblings in development. This is a significant disadvantage for the younger birds, thus usually only two chicks per nest survive to fledging.
The numbers of nesting pairs has continually risen since the program began in 1996 with a record 27 nests in 2004. Natural nests are now found in 18 counties and have produced over 150 chicks that successfully fledged since 1996. The future looks bright for this state-endangered bird as catching glimpses of this magnificent fisher become much more common.
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