| Abstract: | North American ospreys (Pandion haliaetus carolinensis), banded primarily in the Middle Atlantic States and in New England, apparently migrate to their winter grounds in the West Indies and South America on a broad front. Ospreys do not return to the United States as 1-year-olds, but an estimated 28 to 55 percent returrt to their natal vicinity (state where hatched or an adjacent state) as 2-year-olds. The 2-year-olds (presumably nonbreeders) are estimated to represent 5 to 10 percent of the population on the northern breeding grounds. Nest studies suggest that about 6 percent 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 to be 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, we believe the observed recruitment rates can be validly compared with the recruitment standard (production rate required to maintain a stable population) of Henny and Wight (1969). |
| Genre: | Article |
| ProdID: | 5220959 |
| Citation Author: | Henny, C.J.; Van Velzen, W.T. |
| Citation Contributing Office: | Patuxent Wildlife Research Center |
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| Citation End Page: | 1141 |
| Citation Issue: | 4 |
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| Citation Language: | English |
| Citation Larger Work Title: | Journal of Wildlife Management |
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| Citation Number Of Pages: | 9 |
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| Citation Phsyical Description: | 1133-1141 |
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| Citation Search Results Text: | Migration patterns and wintering localities of American ospreys; 1972; Article; Journal; Journal of Wildlife Management; Henny, C.J.; Van Velzen, W.T. |
| Citation Start Page: | 1133 |
| Citation Volume: | 36 |
| Citation Year: | 1972 |
| Type: | citation/reference |
| Text: | Migration patterns and wintering localities of American ospreys; 1972; Article; Journal; Journal of Wildlife Management; Henny, C.J.; Van Velzen, W.T. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DOCUMENT): | http://www.jstor.org/stable/3799242 |
| Date Other: | Wed, 16 Jun 2010 12:17 -0500 |
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