The Annual Return Of Delmarva’s Ospreyby Jim Rapp
Seeing your first Osprey of the year in early March is a sure sign that spring is right around the corner.
This is probably the week that you'll also notice the return of a Delmarva icon to the shores of the Chesapeake, Delaware and Atlantic coastal bays. Seeing your first Osprey of the year in early March is a sure sign that spring is right around the corner. Ospreys migrate back to our Peninsula after spending the winter perched on palm trees under the warm, tropical sun of the Caribbean and Central and South America.
You'll find them soaring effortlessly above the water with their long narrow wings in the shape of an out-stretched letter "M," just waiting to glimpse a shimmering silver perch or menhaden in the water below. If they're hungry, you'll get to witness one of Delmarva's most spectacular wild-bird hunting maneuvers. Immediately after the Osprey zeroes in on its unsuspecting prey, it plunges into the water, talons first, and comes up with a shiny, wriggling fish, which it will carry back to its nest or to a nearby branch. During flight, the Osprey will use it's talons to rearrange the fish so that it is facing head first, thus reducing drag and saving energy while the Osprey is flying.
Unlike other birds of prey that may eat a varied diet of mammals and birds or resort to eating already dead critters when live prey is hard to find, Ospreys feed on live fish only. They are perfectly adapted to life as an avian angler -- their talons are long and sharp, and the bottoms of their feet have rough, pointed scales for holding onto slippery fish. While most raptors have three toes that point forward and one toe pointing back, Osprey have an opposable toe. They can move this special toe forward and backward to get a better hold on their lunch.
Once they're spotted, very few fish ever escape the Osprey's powerful focus and death grip. Studies have shown that Ospreys can catch a fish at least once out of every 4 dives, with some birds having as high as a 70% success rate. Most Osprey don't have to hunt more than 10 or 12 minutes before snagging a fish. I don't know any human anglers with catch rates that good.
Osprey will often perch close to human level, which provides easy viewing of their beautiful, distinctive colors. Ospreys are mostly chocolate-brown on their uppersides and white below. Dark brown stripes run from the base of the beak to the back of the head, and are pierced by bright yellow eyes. They are smaller than a Bald Eagle but bigger than a Red-tailed Hawk, with a body length around 23 inches and a wing span of more than 5 feet. As with most birds of prey, females tend to be a little bit bigger than males.
They come back to Delmarva's shores each year to mate, nest and raise their young. Ospreys start breeding around the age of three, and mated pairs usually return to the same nest site year after year. Their large nests made of sticks and marsh grass are a common sight near Delmarva marinas and waterside parks. Ospreys will build their nests on just about anything near the water: channel markers, buoys, telephone poles, cell phone and electric towers, and even the masts of infrequently-used sailboats have provided structure for osprey nests. Very soon, you'll see Osprey in flight trailing long sticks and reeds from the forest and marsh to fortify their nests.
By mid-April, three or four brown-speckled eggs a little bit bigger than a chicken's are laid. Both the male and female help incubate the eggs for about 5 weeks. When they hatch, babies are no more than 2-ounce helpless little puffballs.
Life can be tough in the Osprey nest. The first chick may hatch up to five days before the last one, and the older sibling can monopolize the fish brought by the parents. If fish are plentiful, everyone eats and gets along. If fish are scarce, the young ones can have a hard time competing with older brothers and sisters. After just eight weeks, the surviving youngsters are ready for life as an aerial acrobat.
If you get too close to a nest during chick season, you'll likely be yelled at by an angry parent with their distinctive call: (Osprey audio)
This is a warning you for you to steer clear of their babies. It's always a good idea to be respectful and move along after your scolding.
After a summer spent fishing and flying on Delmarva, Ospreys take to the skies to begin their southern migration. Ospreys from further north will cruise through on their way south, and hundreds can be counted on good days at Delmarva's regional migration passages.
The osprey can be found on every continent except for Antarctica. We're fortunate here on Delmarva that today, Osprey are a common sight along the Delaware Bay, our coastal bays, and the Chesapeake. This wasn't always the case. After World War II, a popular pesticide known as DDT was sprayed on farmer's fields to kill unwanted insects. Little was known at the time about the horrible ecological side effects of DDT, which included the thinning of eggshells in wild birds.
Ospreys, Bald Eagles, Brown Pelicans and other fish-eating birds seemed to get hit the hardest, and by the 1970s, many of these species were nearly extinct. Osprey populations declined almost 90% from the early 1950s to 1972, when DDT was banned by the U.S. Environmental Protection Agency. We're thankful and appreciative to those scientists and early environmental advocates who pressured the government to ban the use of DDT in 1972, which lead to the comeback of the Osprey and other birds along Delmarva's shores.
To help the Osprey along its recovery route following the DDT ban, many of Delmarva's waterside landowners constructed osprey nesting platforms on their property. This was a huge help to bolstering diminished populations of this species. Even today, these platforms seem to be preferred by Ospreys looking for the perfect place to build their nests and raise young.
If you want to see Ospreys and other spring migrants in the wild, join the expert guides leading field trips during the Delmarva Winter Birding Weekend, which will be held April 21 through 24. For more information, please visit www.DelmarvaBirding.com.
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