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Osprey By Barb Glass ... With photos by Larry Kirtley (reprinted from Prairie Smoke) Index In summer, Osprey are a common sight along the waters in our area. Appropriately, an Osprey is featured on the logo of the City of Kawartha Lakes, Carden’s regional municipality. In the mid-twentieth century, Osprey were seriously endangered by the effects of pesticides. But since the ban of DDT and many related pesticides in the 1970s, Osprey have made a comeback in many parts of North America.
The
Osprey is a large raptor. It averages 58 cm (23 in) in Canal Lake Causeway Osprey Osprey is a single species of raptor, occurring in most areas of the world but most widespread in North America and Australia. The North American race is Pandion haliaeetus carolinensis. “Osprey” comes from the Latin “ossifragus” meaning “bone breaker”. “Pandion” was the name of two mythical rulers of Athens; “haliaeetus” combines the Greek words “hals” and “aetos” meaning “sea” and “eagle”. What an appropriate nomenclature for this fishing expert. It hovers frequently when hunting over water, and dives feet-first into the water to capture fish in its talons. The Osprey’s feet are uniquely adapted with reversible outer toes (like owls) and sharp spiked scales (spicules) on the bottom of the toes. These specialized adaptations enable the Osprey to grasp slippery fish and carry them, head forward, to a perch or nest. Their nests are substantial structures, made of sticks and lined with finer materials to cushion the eggs and prevent them from being wedged into the twigs. Osprey will reuse a nest, adding more sticks each year so the nest becomes huge. Typically nests are in the tops of dead trees or on man-made structures such as platforms, utility poles and channel markers. Ground nests have been reported on islands. Osprey nest sites are usually very open to the sky. A clutch of two or three cream eggs with brown blotches are incubated by both parents, but primarily the female, for about five weeks. She remains with the young most of the time to shelter them from wind, rain and sun. The male brings fish to the nest, and the female feeds them to the young. The young make their first flight about seven or eight weeks after hatching. So, there is a summer-long project involved in one brood. Sometimes one Osprey male mates with two females within the same breeding season.
Osprey
building nest on man-made platform
In
North America, all Ospreys are migratory, except for a resident population in
South Florida. Raptors, including Osprey, migrate by day presumably because
daytime wind conditions are more favourable. In fall migration, the mean
altitude of Osprey flight is greater than 800 m. Migrants travel singly, not in
flocks, often following coastlines, lakeshores, rivers or mountain ranges.
Winters are spent in the Caribbean, Central America or northern South America.
All one-year-olds remain south on the wintering grounds during their second
summer. Two-year-olds return north, sometimes to their natal areas, but do not
breed. A good number of three-year-olds begin to breed. The Osprey Monitoring Project of the Carden Field Naturalists aims to identify and locate nests in the Carden area (using GPS), monitor nesting activity, and assess potential habitat for erecting nesting platforms. Nora Bayles has headed this initiative since it began. At each CFN meeting, a summary of this project is available for viewing. Please consider helping Nora with this project next summer when the Osprey return to our area.
REFERENCES: Clark, William S. A Field Guide to Hawks of North America. Houghton Mifflin. 1987 Kaufman, Kenn Lives of North American Birds. Houghton Mifflin. 1996 National Audubon Society The Sibley Guide to Bird Life & Behavior. Knopf. 2001
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