Oecologia

, Volume 36, Issue 2, pp 127–139 | Cite as

The influence of environmental conditions on aspects of the time budgests of breeding ospreys

  • Christopher H. Stinson
Article

Summary

Ospreys (Pandion haliaetus) were observed for 350 h in 1975 in southeastern Virginia. Other studies have demonstrated that weather can have an effect on aspects of osprey foraging behavior (e.g., frequency of diving), but for the environmental conditions observed in this study, weather and other variables did not appear to limit the ability of ospreys to feed their young.

Male ospreys, which procure essentially all of the food for the family unit before the chicks fledge, spend an average of 43% of the daylight hours perched near the nest when they have unfledged young. About 1/3 of the daylight hours are utilized for hunting. Weather conditions have no effect on the time the male his perched near the nest, or on the rate of fish delivery by the male. Wind speed variability regressed positively with the time it took males to return with a fish (mean time=0.64 h/fish), but accounted for only 16% of the variation in the length of hunting trips. Size of fish delivered and rate of fish delivery were unrelated to either brood size or age of young. As the chicks age, the male spends increasing amounts of time away from the nest; this is not related to changes in weather, and appears to be due to decreasing attentiveness at the nest site by the male. Females with unfledged young spent over 95% of the daylight hours at the nest.

Adults with fledged but dependent young spend an average of 1/3 of the day perched near the nest. Both adults deliver fish at this time, but together they bring no more than the male alone brought before fledging. For both adults neither the percentage of time perched near the nest nor the rate of fish delivery are related to weather conditions.

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References

  1. Barr, A.J., Goodnight, J.H.: A user's guide to the statistical analysis system. Raleigh, N.C.: North Carolina State University 1972Google Scholar
  2. Beebe, F.L.: Field studies of the Falconiformes of British Columbia. Victoria, B.C., Occasional Papers of the British Columbia Provincial Museum No. 17 (1974)Google Scholar
  3. Donn, W.L.: The earth: Our physical environment. New York: Wiley 1972Google Scholar
  4. Draper, N.R., Smith, H.: Applied regression analysis. New York: Wiley 1967Google Scholar
  5. Dunn, E.K.: Changes in fishing ability of terns associated with windspeed and sea surface conditions. Nature 244, 520–521 (1973)Google Scholar
  6. Dunn, E.K.: The role of environmental factors in the growth of tern chicks. J. Anim. Ecol. 44, 743–754 (1975)Google Scholar
  7. Finlay, J.C.: Some effects of weather on Purple Martin activity. Auk 93, 231–244 (1976)Google Scholar
  8. Green, R.: Breeding behaviour of Ospreys Pandion haliaetus in Scotland. Ibis 118, 475–490 (1976)Google Scholar
  9. Grubb, T.C., Jr.: Weather-dependent foraging in Ospreys. Auk 94, 146–149 (1977)Google Scholar
  10. LeCren, E.D.: The length-weight relationship and seasonal cycle in gonad weight and condition in the perch (Perca fluviatius). J. Anim. Ecol. 20, 201–219 (1951)Google Scholar
  11. Markle, D.F.: The seasonality of availability and movements of fishes in the channel of the York River, Virginia. Chesapeake Sci. 17, 50–55 (1976)Google Scholar
  12. Nie, N.H., Hull, C.H., Jenkins, J.G., Steinbrenner, K., Bent, D.H.: SPSS Statistical package for the social sciences. 2nd ed. New York: McGraw-Hill 1975Google Scholar
  13. Snyder, N.F.R., Snyder, H. A.: Experimental study of feeding rates of nesting Cooper's hawks. Condor 75, 461–463 (1973)Google Scholar
  14. Stinson, C.H.: The evolutionary and ecological significance of the clutch size of the osprey (Pandion haliaetus. Williamsburg, Va., M.A. thesis, College of William and Mary (1976)Google Scholar
  15. Stinson, C.H.: Familial longevity in Ospreys. Bird-Banding 48, 72–73 (1977a)Google Scholar
  16. Stinson, C.H.: Growth and behaviour of young ospreys Pandion haliaetus. Oikos 28, 299–303 (1977b)Google Scholar
  17. Ueoka, M.L.: Feeding behavior of ospreys at Humboldt Lake, California. Arcata, Ca., M.S. thesis, Humboldt State College (1974)Google Scholar
  18. Ueoka, M.L., Koplin, J.R.: Foraging behavior of Ospreys in northwestern California. Raptor Res. 7, 32–38 (1973)Google Scholar
  19. U.S. Department of Commerce: Tide Tables, High and Low Water Predictions, 1975, East Coast of North and South America including Greenland. Washington, D.C.: U.S. Government Printing Office 1975Google Scholar
  20. Waterston, G.: Notes on the breeding biology of the Speyside Ospreys—1959 and 1960. Bird Notes 29, 130–135 and 174–184 (1961)Google Scholar

Copyright information

© Springer-Verlag 1978

Authors and Affiliations

  • Christopher H. Stinson
    • 1
  1. 1.Department of BiologyCollege of William and MaryWilliamsburgUSA
  2. 2.Department of Zoology NJ-15University of WashingtonSeattleUSA

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