A Remarkable Bird

     Take a guess:  what bird mates for life, returns to the same nest every year, migrates up to 3500 miles in autumn and again in spring in a state of semi-sleep, and can spend forty hours in the air at 25-30 mph without stopping?

   

Nest on Westport River, Massachusetts

Nest in shallow water on left

     The answer?  An osprey.

     In both Florida and Massachusetts, we live near osprey breeding grounds. We see their nests, the size of queen beds, made from anything the scavengers can lift. They balance on platforms at the top of high poles or on man-made structures like bridges. Some of the platforms have been erected by the Audubon Society.

Osprey nest on Westport River. Note piece of scrap iron hanging from bottom right.

     The Intracoastal Waterway in Florida and branches of the Westport River, Massachusetts (leading into Buzzard’s Bay below Cape Cod), provide supplies of fish, the birds’ only diet.

Buzzard's Bay, Massachusetts

     Their curved talons and an under-surface on their toes consisting of short spines allow them to hold squirming fish while flying. Once when my mother was visiting us in Massachusetts, a foot-long, wet fish landed next to her on the deck. "Why were you throwing a fish at me?" she later asked her son-in-law (Charley).   
      “Evelyn,” Charley said, laughing, “I was working on the other side of the house and wouldn’t have had the strength to throw a heavy fish that far. Besides, I would never throw anything at you! An osprey probably let go.”

     Twenty years ago, the osprey became endangered in the U.S. The pesticide DDT caused the birds’ eggshells to become thin. As a result, the young exhibited symptoms of pesticide-poisoning or never hatched. After DDT was banned in the 1970’s in the U.S., the osprey population rebounded. The population worldwide today is estimated at 460,000. 

Adult osprey in flight

      Typically, two to four eggs are laid in April, always in the same breeding ground and in the same nest. Incubation lasts approximately 38 days. Fledglings may leave the nest at 44-59 days, but will still rely on parental care for six weeks. Sexual maturity isn’t reached till age three. A typical lifespan is seven to ten years, with their only known predators the great horned owl, golden eagles, and bald eagles.

Juvenile osprey in flight

     In shallow inland or coastal fishing waters, winter brings ice in northern regions. Fish head away from the surface, making it almost impossible for osprey to spot them from the air, despite their dense and oily plumage for diving feet-first. The larger-bodied mother leaves the nest first in late August through November, to migrate from North America to the shallow waters of Central and South America. Those residing in California and Florida don’t migrate.The Westport Watershed Alliance, Massachusetts, has placed transmitters on a sample population, allowing GPS signals to trace the migration thousands of miles.

     Ospreys can rest half their brains en route, shutting one eye and letting half their brain sleep. They fly in hot air rising (thermals) for hours without flapping their wings. When they start to lose altitude, they drop, glide, and search for another thermal. Their high-pitched chirps mingle with the wind.

     The father leaves the nest second to join his mate, and finally the juveniles. In late March or early April they make the return trip to breed.

A lone juvenile staring down at me in October from his nest on the Westport River, before leaving to migrate