General
description: An osprey is a large bird with a length of 22-25
inches, a wingspan of 4.5-6 feet, and a weight of approximately
four pounds. The osprey has a dark brown back and a white belly,
as well as a white head, which features
a dark stripe running from its yellow eyes to the back of its head.
Female ospreys are slightly larger than males and may sport a dark
speckled necklace. Ospreys are seen in the Chesapeake Bay area from
spring through fall, but are rare in the winter. North American
ospreys winter in Florida, the Caribbean, on the Gulf Coast, and
in South America.
Eating behavior:
The osprey dines almost exclusively on live fish, often catching
its meals by hovering over the water at an altitude of 50 to 200
feet, then diving feet-first into the water to catch its prey. The
osprey's feet are uniquely adapted to "air fishing." Each
osprey foot has a reversible front toe, as well as barbs, called
spicules, which help it hold onto a slippery fish in flight. Normally,
an osprey will aerodynamically position a fish head-first in its
talons before it returns to the nest.
Nesting
behavior: Like bald eagles, ospreys often reuse old nests, adding
new material to them each season. Ospreys prefer nests near water,
especially in large trees, but will also nest on artificial platforms.
The female osprey usually lays three eggs, which will hatch in about
4 to 5 weeks. After about 10 weeks, the young will have all their
flight feathers. The female will stay on the nest the majority of
the time, with the male giving her an occasional break when she
leaves to hunt for food.
Threats:
Like many birds of prey, the osprey suffered during the 60s and
70s due to the rampant use of DDT and other dangerous pesticides.
Research done at Maryland's Patuxent Wildlife Research Center laid
the foundation for Rachel Carson's classic "Silent Spring,"
which alerted citizens, scientists, and politicians to the fact
that DDT was working its way up the food chain and thinning the
eggs of birds of prey. Fortunately, DDT was banned in the U.S. in
1972, and thanks to the hard work of many dedicated people, including
Dennis Puleston, birds of prey are beginning to rebound.
Other interesting
osprey facts from Alan Poole's "Ospreys: A Natural and Unnatural
History" (Cambridge University Press, 1989):
- ospreys generally
pair for life, but if mating is unsuccessful, will sometimes "divorce"
- a female
osprey will choose her mating partner based on the quality and
location of the male's nest
- osprey nests
have been known to contain hula hoops, rag dolls, and toy boats
- osprey parents
will hold back food in order to encourage fledglings to leave
the nest
- osprey fledglings
will sometimes move to nearby nests where they are fed by other
parents
(Source: Blackwater
Refuge Web site) |