Saturday, September 1, 2012

Late Bloomers

Adult Osprey (c) John Ashley
Fall is in the air - and heading southward. Reports of migrating songbirds are filtering in. Sparrows, warblers, even a few immature hawks. Many female and juvenile hummingbirds headed south a week or two ago, and most adult males left more than a month ago.

Meanwhile we still have a number of late-blooming, juvenile Osprey hanging out in their parents' nests, eating leftovers. Their feathers are slightly browner and duller than adult plumage.

The young Osprey learned to fly more than a month ago. Since then many of them have been making frequent, short, exploratory flights over their neighborhoods and back to the nest again. The exercise builds their flight muscles and allows instincts to kick in, as they also start making their first attempts at fishing. 

Learning to fish can't happen soon enough for the juveniles, because the parents will often leave before them. The adult female usually leaves first, in late summer almost a month before her mate and young ones leave. Adult Osprey from the Pacific Northwest spend an average of 14 days migrating south, flying 60-236 miles per day while making a beeline for wintering areas in Mexico and Central America. Osprey from the eastern U.S. tend to winter further south, in the northern parts of South America.

Most of our juveniles will eventually head south on their own, not necessarily following the same route as their parents. They'll winter north of the adults, and the young Osprey will not return north until their second or third spring - staying south for their first year or two. Most of them won't breed until age 3 or 4, and sometimes older.

When old enough to breed, male Osprey show more fidelity to the area where they were born. In one small study, all young males and 80% of young females returned to within 30 miles of their natal areas. After they finally reach breeding status, they'll settle in and begin raising their own late bloomers.