Migration Patterns and Wintering Localities of American Ospreys
Henny CJ and Van Velzen WT. 1972. Migration Patterns and Wintering Localities of American Ospreys. The Journal of Wildlife Management. 36(4):1133-1141
North American ospreys migrate to their winter grounds in the West Indies and South America. Ospreys do not return to the United States as 1-year-olds, but an estimated 28-55% return to their natal vacinity as 2-year-olds. The 2-year-olds are estimated to represent 5 to 10% of the population on the northern breeding grounds. Nest studies suggest that about 6% of the population on the breeding grounds consists of nonbreeders, presumably the 2-year-olds. These birds are associated with nests but do not lay eggs or exhibit brooding behavior. The point made to individuals conducting nest studies on ospreys is that nests should not be classified as active if eggs are not laid, even though a pair is present. If nests with no eggs are excluded from studies, the authors believe the observed recruitment rates can be validly compared with the recruitment standard of Henny and Wight (1969).
- Type
- Journal Article
- Authors
- Henny, Charles; Van Velzen, Willet
- Units
- VOYA
- Keywords
- Animal Studies, Breeding Population, Migration Patterns, Nests & Nesting, Osprey (Pandion haliaetus)