Click on speaker to hear the Osprey!Osprey (Pandion haliaetus)
Click on speaker to hear the Osprey!
FLIGHT AND HUNTING: Ospreys are fish hawks that have brown and white markings on their bellies. They can soar on wind currents, but most of their flight is active (with wings flapping.) Ospreys hunt by flying over the water looking for fish. They hover before diving towards the water, then plunge in feet-first. Mullet are a good prey fish in Florida because they school together, swim in shallow water, and are rich in fat. Ospreys usually hunt alone, during early morning and late afternoon. Ospreys that are not parents need to catch about 1 - 3 fish a day. A breeding male, who must fish for 2-3 babies and a mate, has to catch 6-8 fish a day. Ospreys have special adaptations (things about the way their body is built) that make them better fish-hunters. For one thing, the bottoms of their feet have many short spines which help them to hang onto a slimy fish. Many birds have three toes and a thumb, but the osprey can turn his third toe around, so he can have an extra-strong grip with two fingers and two thumbs. Ospreys have extremely sharp talons and a strong hooked beak for tearing fish into bite-sized pieces. They also have very oily feathers which help keep them dry when they splash into the water.
NESTING and RAISING BABIES: Ospreys like to make their nests in dead trees because there are no leaves to get in the way of their wings. It is also harder for predators (dangerous animals) to climb a dead tree without the osprey seeing it. Many ospreys build nests on power poles when there aren’t enough dead trees around. Ospreys are able to mate (have babies) at 3 years old. When a male is ready to court (date) a female, he performs the "Sky Dance" by flying around with a newly-caught fish or nesting material. Ospreys mate for life, and mated pairs come back to the same nest year after year. If the pair has no nest, they both collect materials, like sticks and grass. Sometimes they also pick up plastic bags and fishing wire (which can kill the babies). Year after year, the ospreys make these nests bigger and stronger so they won’t get knocked down by high winds. An osprey nest can weigh up to 1000 pounds, but it is not very deep inside and probably could not hold a person. Florida ospreys stay in Florida year round and lay their eggs between December and February. (North of Florida, ospreys migrate south each year.) The eggs are about the same size as a chicken egg. They are cream-colored with spots. Both parents sit on the eggs. The mother does most of the sitting, and the father feeds her. Ospreys usually lay 3 eggs. When there isn’t much food, the larger babies will peck at the smallest baby so they can get first chance at the food. There is a good chance this runt will die of starvation. 10-15 days before fledging (flying), the young ospreys practice flapping their wings. They jump up and down on the nest until a wind gust carries them over the edge on their first flight. Osprey parents will fly past the nest with a fish and drop it into the water to help the babies catch their first fish. The babies can usually catch their own fish 2 or 3 days after fledging, but the parents will still bring food for a few weeks.
HISTORY AND FUTURE: It’s not easy for ospreys to find a strong dead tree for their nest. Many ospreys also have a hard time finding enough fish to feed their babies. Man has caused some problems for the ospreys too. Fertilizers and other pollution can run off into the water and kill the fish; (this means the ospreys won’t have enough fish to eat.) Timber harvesting (cutting down trees) makes it harder for them to find a place for their nests. Cutting down trees in the rain forest destroys the ospreys’ wintering grounds (where they stay in the winter if they migrated south). Some ospreys get shot even though it is against the law to hunt them. People also put some dangerous chemicals into the environment, like DDT. Fish soak up DDT from the water. Since ospreys only eat fish, they get a lot of this DDT. This hurts them in 2 ways. First, it makes their egg shells thin, so the eggs crack when the mother sits on them. Second, since these DDT eggshells don’t let much air through, the baby may not be able to breathe inside the shell. In the 1970’s, after people stopped using DDT, many more osprey babies survived. These fish hawks are a "threatened species" (protected by law) in Florida. Now, people are trying NOT to pollute the water, NOT to shoot ospreys, and NOT to leave fishing line out for them to get caught in. A good way to help ospreys is to build nesting platforms for them (tall poles that the ospreys can build their nests on). The Jacksonville Electric Authority (JEA) has put up several platforms to provide safe nesting spots in Jacksonville.
REFERENCES:
Poole, Allen. Ospreys: A Natural and Unnatural History. Cambridge: Cambridge University Press., 1989.
Terres, John K. The Audubon Society Encyclopedia of N. American Birds. New York: Alfred A. Knopf, Inc., 1987.
Provided by the E. Dale Joyner Nature Preserve at Pelotes Island