Over the years I have observed a pair of Osprey, who has nested, raised their young, enjoyed their fishing skills, and marveled their acrobatics over the water on the Chippewa Flowage.
The Osprey, also known colloquially as fish fishhawk, seahawk, or fish eagle is a medium to large fish eating bird of prey. This raptor is found on all continents except Antarctica-in South America is occurs as a non-breeding migrant. The Osprey is widely distributed because it tolerates a wide variety of habitats, nesting in any location which is near a body of water and provides an adequate food supply.
The Osprey is a medium sized raptor, reaching 24 inches in length, weights in at 3 to 4 pounds, and a wingspan at about 6 feet. The upperparts are a deep, glossy brown, while the breast is white and sometimes tweaked with brown, and the underpants are pure white with a dark mask across the eyes, reaching to the sides of the neck. The irises of the eyes are golden to brown. The bill is black, with a blue tinge, and the feet are white with black talons. The Osprey has a short tail and long, narrow wings with four long fingerlike feathers, and a shorter fifth, give it a very distinctive appearance. The sexes appear fairly similar, but the adult male can be distinguished from the female by its slimmer body and narrower wings. In flight, the Osprey has arched wings and dropping legs and talons—-giving it a gull-like appearance. The call is a series of sharp whistles, described as cheep, cheep or yewk, yewk. A frenzied call can be heard around the nest site as a chereek!
Osprey’s diet consists almost exclusively of fish—-it has evolved particular physical characteristics and exhibits some unique behaviors to assist in hunting and catching prey.
Its toes are of equal length and its talons are rounded rather than grooved. The Osprey is the only raptor whose outer toe is reversible, allowing it to grasp its prey with two toes in front.
The Osprey is highly successful to its tolerance of a wide range of habitats. It will nest in any location near a body of water which provides safety and an abundance of fish. Marsh, mangrove, swamp, cypress swamp, lake, bog, reservoir or river, even a man-made platform on high electric wire poles become nesting sites for the Osprey.
Fish makes up about 90 percent of the Osprey’s diet. Typically takes fish weighing 6 to 10 ounces and about 10 to 12 inches in length. Prey is first sighted when the Osprey is about 30 to 40 yards about the water, after which the bird hovers momentarily then plunges feet first into the water. It is able to dive to a depth of 3 plus feet. The angle of entry into the water varies with the prey the Osprey is pursuing—whether it requires a deep dive or a surface snatch. After the catch, the Osprey requires considerable effort to get airborne again. As it rises back into flight the fish is turned head-forward to reduce drag.
The Osprey is particularly well adapted to a fish diet; reversible outer toes, sharp speckles on the underside of the toes, closable nostrils, and backward s facing scales on the talons which act as barbs to help hold it catch. Interestingly, the "barbed" talons are such effective tools for grasping fish that on occasion an Osprey may be unable to release a fish that is heavier than expected. This can cause the bird to be pulled into the water, where it may either swim to safety or drown.
The nest site of the Osprey is a large heap of sticks, driftwood, and weeds in trees, rocky outcrops, telephone poles, artificial platforms or off shore islets. Some nesting sites have been known to be active for over 70 years. Ospreys reach sexual maturity and begin breeding around age 3 or 4 years and usually mate for life. In the spring the pair begins a five month partnership to raise their young. The female lays 2 to 4 eggs, are whitish in color, and requires about a 5 month incubation period before hatching. The typical life span for the Osprey is about 20 to 25 years.
Osprey populations declined in many areas in the 1950’s due to the toxic effects of insecticides such as DDT on reproduction—-resulting in a thin-shelled eggs and easily broken in the nest or infertile eggs. DDT was banned in many countries in the early 1970’s which has resulted in significant recoveries of the Osprey and other birds of prey species.
I look forward to each new spring season and the return of these wonderful creatures on the Chippewa Flowage—- the Osprey is another gift to enjoy on this treasured body of water in northwest Wisconsin.
My thanks are extended to Wikopedia and the Free Press Encyclopedia as one of my sources for this narrative.
I would like to thank Jim Edlhuber for allowing me to share these images with you which he photographed in June 2007 while vacationing at Treeland Resorts