Fish & Wildlife
Friday, May 29, 2009
Observing osprey on their nests in dead trees or on lofty manmade nesting platforms is a favorite activity of many and the viewing on land and online is in full swing.
If you query the Internet for "osprey cams," you will see that the osprey is an Internet star, as well as a popular bird in the field.
One reason may be the osprey's inherent drama. It is a large bird, weighing about four pounds with a wingspan of four to six feet, and striking dark brown and white coloring. It lives exclusively on fish by hunting in long, slow flights over water and with breath-taking dives from heights of 30 to 120 feet. The osprey plunges feet first into the water after prey, even submerging itself in the pursuit, and is still able to take to the air carrying its prey.
When an osprey's hunt is successful, its opposable toe is handy. The toe can face forward or backward and it allows the osprey to grasp its catch with two toes on either side, with the fish facing forward in a streamlined position for transport to the nest.
By the third week of April the female osprey usually lays three to four eggs, one to two days apart. The eggs are similar to large chicken eggs with light brown splashed with red, brown and gray blotches. In 35 to 40 days, the eggs hatch in the order in which they were laid. Chicks learn to fly, or fledge, about 55 days after hatching, but remain at their home base until they migrate in September.
The osprey's family habits are also colorful and interesting. They generally pair for life and reuse old nests, adding new material each season. Their nests, in high, dead trees or on manmade elevated platforms, can weigh hundreds of pounds and are easily observed. Osprey refurbish their nests annually with grass, lichens, and sticks.
Observers also report seeing small plastic toys, deer antlers, even trash in nests that pose a hazard to the birds. One of the most hazards is baling twine.
In 2007, two students from Missoula's Hellgate High School—Max Egenhoff and Matt Parker—studied ospreys' attraction to baling twine and found that when twine entangled the birds it was fatal to 10 percent of osprey chicks in some areas. FWP recognized the research with an Outstanding Science award at the 2008 Montana State Science Fair.
Erick Greene, of the Division of Biological Sciences and the Wildlife Biology Program at the University of Montana, and a coalition of high school and undergraduate students and colleagues, continue to study the status and needs of osprey.
This summer, Greene and his team will communicate what they've learned about osprey and how Montana communities can help. Farmers and ranchers, volunteers and others are already removing baling twine from the landscape, he said, and learning more about these popular birds.
To learn more, see the pamphlet on the Montana Audubon Web site at mtaudubon.org on the Birds and Science page under About Birds. For more about osprey, go to Montana's online field guide at the FWP home page fwp.mt.gov under Guides and Planners.