Factors affecting the growth of a black guillemot colony in northern Alaska
Dissertation (Ph.D.) University of Alaska Fairbanks, 1998 Annual variation in breeding populations at seabird colonies has been well documented, but there have been few long-term attempts to examine the environmental and demographic forces responsible. I studied breeding chronology and demography Bl...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/9472 2023-05-15T15:44:51+02:00 Factors affecting the growth of a black guillemot colony in northern Alaska Divoky, George Joseph 1998 http://hdl.handle.net/11122/9472 unknown http://hdl.handle.net/11122/9472 Department of Biology and Wildlife Ecology Zoology Dissertation phd 1998 ftunivalaska 2023-02-23T21:37:16Z Dissertation (Ph.D.) University of Alaska Fairbanks, 1998 Annual variation in breeding populations at seabird colonies has been well documented, but there have been few long-term attempts to examine the environmental and demographic forces responsible. I studied breeding chronology and demography Black Guillemot in northern Alaska from 1975-1997 to identify the factors responsible for colony establishment and growth. The Black Guillemot is a cavity-nesting seabird whose populations are frequently limited by nest-site availability. Snowmelt in spring and snow accumulation in autumn had major effects on annual nesting initiation and success, respectively. Annual arrival at the colony and median date of egg laying was well correlated with the date of snow disappearance, with annual clutch initiation advancing 4.5 days per decade in response to regional climate amelioration. Successful breeding requires a snowfree cavity for ${>}80$ days. Decreased breeding success and post-fledging survival occurred in a year with a snow-free period ${<}80$ days. Historic weather records indicate annual snowfree periods ${>}80$ days were uncommon until the 1960's, when the species was first recorded breeding in northern Alaska. When additional nest sites were provided, growth of the colony was rapid, increasing from 18 pairs in 1975 to 225 pairs in 1989. Breeding numbers then decreased to 150 in 1996 as factors other than nest-site availability controlled population size. Doctoral or Postdoctoral Thesis Black guillemot Alaska University of Alaska: ScholarWorks@UA Fairbanks |
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Open Polar |
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University of Alaska: ScholarWorks@UA |
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ftunivalaska |
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unknown |
topic |
Ecology Zoology |
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Ecology Zoology Divoky, George Joseph Factors affecting the growth of a black guillemot colony in northern Alaska |
topic_facet |
Ecology Zoology |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 1998 Annual variation in breeding populations at seabird colonies has been well documented, but there have been few long-term attempts to examine the environmental and demographic forces responsible. I studied breeding chronology and demography Black Guillemot in northern Alaska from 1975-1997 to identify the factors responsible for colony establishment and growth. The Black Guillemot is a cavity-nesting seabird whose populations are frequently limited by nest-site availability. Snowmelt in spring and snow accumulation in autumn had major effects on annual nesting initiation and success, respectively. Annual arrival at the colony and median date of egg laying was well correlated with the date of snow disappearance, with annual clutch initiation advancing 4.5 days per decade in response to regional climate amelioration. Successful breeding requires a snowfree cavity for ${>}80$ days. Decreased breeding success and post-fledging survival occurred in a year with a snow-free period ${<}80$ days. Historic weather records indicate annual snowfree periods ${>}80$ days were uncommon until the 1960's, when the species was first recorded breeding in northern Alaska. When additional nest sites were provided, growth of the colony was rapid, increasing from 18 pairs in 1975 to 225 pairs in 1989. Breeding numbers then decreased to 150 in 1996 as factors other than nest-site availability controlled population size. |
format |
Doctoral or Postdoctoral Thesis |
author |
Divoky, George Joseph |
author_facet |
Divoky, George Joseph |
author_sort |
Divoky, George Joseph |
title |
Factors affecting the growth of a black guillemot colony in northern Alaska |
title_short |
Factors affecting the growth of a black guillemot colony in northern Alaska |
title_full |
Factors affecting the growth of a black guillemot colony in northern Alaska |
title_fullStr |
Factors affecting the growth of a black guillemot colony in northern Alaska |
title_full_unstemmed |
Factors affecting the growth of a black guillemot colony in northern Alaska |
title_sort |
factors affecting the growth of a black guillemot colony in northern alaska |
publishDate |
1998 |
url |
http://hdl.handle.net/11122/9472 |
geographic |
Fairbanks |
geographic_facet |
Fairbanks |
genre |
Black guillemot Alaska |
genre_facet |
Black guillemot Alaska |
op_relation |
http://hdl.handle.net/11122/9472 Department of Biology and Wildlife |
_version_ |
1766379225841926144 |