July 20, 2007
By Sue Benson,
Director of Education, CNHM
Flight of the Fish Hawk
On a lazy summer day at your favorite lake or river, chances are good you’ll spot a bald eagle soaring high overhead or looking down from its perch on the upper branches of a big white pine. Thanks to cleaner waterways, habitat preservation, and federal and state protection, the once-rare eagle is now a common sight in the north woods.
While scanning the skies, though, you may be lucky enough to catch sight of another big raptor, one less common than the eagle but also found along rivers, lakes or wetlands. With a six-foot wingspan and a white head, the osprey might be mistaken for a bald eagle, though a closer look will reveal the bird’s distinguishing characteristics.
Perhaps most notable are the osprey’s wings, which look somewhat crooked because in flight they’re angled backward at the wrist. In contrast to the dark-bodied bald eagle, the underside of an osprey’s head, neck, chest, legs and wings are white; its tail is a mix of white and brown stripes.
Also known as the “fish hawk,” the osprey eats almost exclusively fish. The bird hovers over open water until it eyes its prey, then plunges downward feet first to grab the unsuspecting fish. Ospreys can’t swim, and occasionally drown when they latch on to a fish too large to lift from the water.
While bald eagles may spend the winter up north, ospreys migrate to warmer southern states in the fall and return to Wisconsin in mid-April to mate and nest. The nests are located near water and built on top of trees, power poles or human-made osprey nesting platforms. The nests themselves are usually more than three feet wide and are made of big sticks lined with grasses and weeds. During the month it takes for eggs to incubate, the female osprey rarely leaves the nest, while the male brings her fish to eat.
Though ospreys live on all continents except Antarctica, they have never been numerous in Wisconsin. In the 1950s, their modest population declined due to the harmful impacts of pesticides like DDT. Once these substances were banned in the early 1970s, osprey populations began to recover. In 1989 the osprey was reclassified from “endangered” to “threatened” in Wisconsin, but seeing these powerful, graceful birds remains a rare, exciting treat.
Brought to you by the Cable Natural History Museum. For 40 years, the Museum has served as a guide and mentor to generations of visitors and residents interested in learning to better appreciate and care for the extraordinary natural resources of the region. They invite you to visit their facility in Cable on 43570 Kavanaugh Street or at the website at http://www.cablemuseum.org/ to learn more about their exhibits and programs.