Clutch size and initiation date of ospreys: natural patterns and the effect of a natural delay
We studied the breeding performance of ospreys (Pandion haliaetus) in southeastern British Columbia from 1987 to 1990. Clutch size, brood size, and the number of young fledged per nest all declined significantly as clutch initiation date was delayed. The quality of later born young as measured by gr...
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1993
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crcansciencepubl:10.1139/z93-300 2023-12-17T10:28:20+01:00 Clutch size and initiation date of ospreys: natural patterns and the effect of a natural delay Steeger, Christoph Ydenberg, Ronald C. 1993 http://dx.doi.org/10.1139/z93-300 http://www.nrcresearchpress.com/doi/pdf/10.1139/z93-300 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Zoology volume 71, issue 11, page 2141-2146 ISSN 0008-4301 1480-3283 Animal Science and Zoology Ecology, Evolution, Behavior and Systematics journal-article 1993 crcansciencepubl https://doi.org/10.1139/z93-300 2023-11-19T13:39:40Z We studied the breeding performance of ospreys (Pandion haliaetus) in southeastern British Columbia from 1987 to 1990. Clutch size, brood size, and the number of young fledged per nest all declined significantly as clutch initiation date was delayed. The quality of later born young as measured by growth rate and the number of fault bars in rectrices did not seem to be reduced. Behavioural observations of the flight-hunting performance of six focal males demonstrated that food availability did not decline in the course of the nestling period. Clutch initiation of some osprey pairs was naturally delayed when their nests were occupied by Canada geese (Branta canadensis). Nest occupation delayed clutch initiation by 9.4 days on average, and reduced clutch size by 0.2 eggs. Osprey pairs possessing an alternate nest were not delayed by the presence of geese in their primary nest, and did not reduce clutch size, suggesting that the clutch size reduction was a direct response to the delay, rather than to the presence, of geese. The results do not support the reduced food availability or reduced breeding commitment hypotheses for seasonal clutch size decline. The data conform to the predictions of the hypothesis that the optimal clutch size is set by a trade-off between the declining reproductive value of later hatched nestlings and the delay required to be able to enlarge the clutch. Article in Journal/Newspaper Branta canadensis Pandion haliaetus Canadian Science Publishing (via Crossref) Canada British Columbia ENVELOPE(-125.003,-125.003,54.000,54.000) Canadian Journal of Zoology 71 11 2141 2146 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics Steeger, Christoph Ydenberg, Ronald C. Clutch size and initiation date of ospreys: natural patterns and the effect of a natural delay |
topic_facet |
Animal Science and Zoology Ecology, Evolution, Behavior and Systematics |
description |
We studied the breeding performance of ospreys (Pandion haliaetus) in southeastern British Columbia from 1987 to 1990. Clutch size, brood size, and the number of young fledged per nest all declined significantly as clutch initiation date was delayed. The quality of later born young as measured by growth rate and the number of fault bars in rectrices did not seem to be reduced. Behavioural observations of the flight-hunting performance of six focal males demonstrated that food availability did not decline in the course of the nestling period. Clutch initiation of some osprey pairs was naturally delayed when their nests were occupied by Canada geese (Branta canadensis). Nest occupation delayed clutch initiation by 9.4 days on average, and reduced clutch size by 0.2 eggs. Osprey pairs possessing an alternate nest were not delayed by the presence of geese in their primary nest, and did not reduce clutch size, suggesting that the clutch size reduction was a direct response to the delay, rather than to the presence, of geese. The results do not support the reduced food availability or reduced breeding commitment hypotheses for seasonal clutch size decline. The data conform to the predictions of the hypothesis that the optimal clutch size is set by a trade-off between the declining reproductive value of later hatched nestlings and the delay required to be able to enlarge the clutch. |
format |
Article in Journal/Newspaper |
author |
Steeger, Christoph Ydenberg, Ronald C. |
author_facet |
Steeger, Christoph Ydenberg, Ronald C. |
author_sort |
Steeger, Christoph |
title |
Clutch size and initiation date of ospreys: natural patterns and the effect of a natural delay |
title_short |
Clutch size and initiation date of ospreys: natural patterns and the effect of a natural delay |
title_full |
Clutch size and initiation date of ospreys: natural patterns and the effect of a natural delay |
title_fullStr |
Clutch size and initiation date of ospreys: natural patterns and the effect of a natural delay |
title_full_unstemmed |
Clutch size and initiation date of ospreys: natural patterns and the effect of a natural delay |
title_sort |
clutch size and initiation date of ospreys: natural patterns and the effect of a natural delay |
publisher |
Canadian Science Publishing |
publishDate |
1993 |
url |
http://dx.doi.org/10.1139/z93-300 http://www.nrcresearchpress.com/doi/pdf/10.1139/z93-300 |
long_lat |
ENVELOPE(-125.003,-125.003,54.000,54.000) |
geographic |
Canada British Columbia |
geographic_facet |
Canada British Columbia |
genre |
Branta canadensis Pandion haliaetus |
genre_facet |
Branta canadensis Pandion haliaetus |
op_source |
Canadian Journal of Zoology volume 71, issue 11, page 2141-2146 ISSN 0008-4301 1480-3283 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/z93-300 |
container_title |
Canadian Journal of Zoology |
container_volume |
71 |
container_issue |
11 |
container_start_page |
2141 |
op_container_end_page |
2146 |
_version_ |
1785580436032847872 |