Population delineation and wintering ground influence on vital rates of white-winged scoters
North American populations of white-winged scoters (Melanitta fusca deglandi) have declined markedly over the past several decades. The causes for decline are uncertain, but likely involve a complexity of events occurring on wintering and breeding areas. To gain insight into potential cross-seasonal...
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ftusaskatchewan:oai:harvest.usask.ca:10388/etd-05022007-145956 2023-05-15T17:10:55+02:00 Population delineation and wintering ground influence on vital rates of white-winged scoters Swoboda, Cindy Jean Alisauskas, Ray T. Hobson, Keith A. Clark, Robert G. Chivers, Douglas P. May 2007 http://hdl.handle.net/10388/etd-05022007-145956 en_US eng University of Saskatchewan http://hdl.handle.net/10388/etd-05022007-145956 TC-SSU-05022007145956 Melanitta fusca deglandi White-winged Scoters δ15N nitrogen-15 carbon-13 δ13C stable isotopes population delineation philopatry cross-seasonal effects blood contaminants text Thesis 2007 ftusaskatchewan 2022-01-17T11:54:10Z North American populations of white-winged scoters (Melanitta fusca deglandi) have declined markedly over the past several decades. The causes for decline are uncertain, but likely involve a complexity of events occurring on wintering and breeding areas. To gain insight into potential cross-seasonal effects, I delineated Atlantic and Pacific wintering scoter populations and linked them to a shared breeding area using stable isotope analysis of carbon (δ13C) and nitrogen (δ15N) ratios in feathers. By applying this methodology to a marked breeding population at Redberry Lake, Saskatchewan, I assigned females to putative wintering areas and determined: (1) population structure; (2) the extent of winter site philopatry; and, (3) differences in vital rates and other variates in relation to winter origin. Discriminant function analysis of isotopic ratios in feather samples from known wintering locations resulted in classification probabilities of 96% (n = 149) for Pacific and 78% (n = 32) for Atlantic wintering scoters. Using this methodology, I determined that the Redberry Lake breeding population is comprised of approximately 75% Pacific and 25% Atlantic wintering birds, and its members exhibit high degrees of winter region philopatry based on the classification of successive recaptures over three field seasons. Annual variations in population structure, as well as differences in nest initiation dates and blood contaminant loads in relation to winter area suggest seasonal interactions may influence survival and reproductive success of this population. To gain insight into potential seasonal interactions, I examined nest success and female survival in relation to winter area. No significant differences in nest success in relation to winter area were found, but nests that failed before mid-incubation were not sampled. Adult female survival rate for 2000-2004 was estimated as 0.85, with no significant difference detected between wintering areas. This study demonstrated that it is important to link breeding and wintering areas to better understand the factors influencing population dynamics and to effectively address conservation issues. Thesis Melanitta fusca University of Saskatchewan: eCommons@USASK Pacific |
institution |
Open Polar |
collection |
University of Saskatchewan: eCommons@USASK |
op_collection_id |
ftusaskatchewan |
language |
English |
topic |
Melanitta fusca deglandi White-winged Scoters δ15N nitrogen-15 carbon-13 δ13C stable isotopes population delineation philopatry cross-seasonal effects blood contaminants |
spellingShingle |
Melanitta fusca deglandi White-winged Scoters δ15N nitrogen-15 carbon-13 δ13C stable isotopes population delineation philopatry cross-seasonal effects blood contaminants Swoboda, Cindy Jean Population delineation and wintering ground influence on vital rates of white-winged scoters |
topic_facet |
Melanitta fusca deglandi White-winged Scoters δ15N nitrogen-15 carbon-13 δ13C stable isotopes population delineation philopatry cross-seasonal effects blood contaminants |
description |
North American populations of white-winged scoters (Melanitta fusca deglandi) have declined markedly over the past several decades. The causes for decline are uncertain, but likely involve a complexity of events occurring on wintering and breeding areas. To gain insight into potential cross-seasonal effects, I delineated Atlantic and Pacific wintering scoter populations and linked them to a shared breeding area using stable isotope analysis of carbon (δ13C) and nitrogen (δ15N) ratios in feathers. By applying this methodology to a marked breeding population at Redberry Lake, Saskatchewan, I assigned females to putative wintering areas and determined: (1) population structure; (2) the extent of winter site philopatry; and, (3) differences in vital rates and other variates in relation to winter origin. Discriminant function analysis of isotopic ratios in feather samples from known wintering locations resulted in classification probabilities of 96% (n = 149) for Pacific and 78% (n = 32) for Atlantic wintering scoters. Using this methodology, I determined that the Redberry Lake breeding population is comprised of approximately 75% Pacific and 25% Atlantic wintering birds, and its members exhibit high degrees of winter region philopatry based on the classification of successive recaptures over three field seasons. Annual variations in population structure, as well as differences in nest initiation dates and blood contaminant loads in relation to winter area suggest seasonal interactions may influence survival and reproductive success of this population. To gain insight into potential seasonal interactions, I examined nest success and female survival in relation to winter area. No significant differences in nest success in relation to winter area were found, but nests that failed before mid-incubation were not sampled. Adult female survival rate for 2000-2004 was estimated as 0.85, with no significant difference detected between wintering areas. This study demonstrated that it is important to link breeding and wintering areas to better understand the factors influencing population dynamics and to effectively address conservation issues. |
author2 |
Alisauskas, Ray T. Hobson, Keith A. Clark, Robert G. Chivers, Douglas P. |
format |
Thesis |
author |
Swoboda, Cindy Jean |
author_facet |
Swoboda, Cindy Jean |
author_sort |
Swoboda, Cindy Jean |
title |
Population delineation and wintering ground influence on vital rates of white-winged scoters |
title_short |
Population delineation and wintering ground influence on vital rates of white-winged scoters |
title_full |
Population delineation and wintering ground influence on vital rates of white-winged scoters |
title_fullStr |
Population delineation and wintering ground influence on vital rates of white-winged scoters |
title_full_unstemmed |
Population delineation and wintering ground influence on vital rates of white-winged scoters |
title_sort |
population delineation and wintering ground influence on vital rates of white-winged scoters |
publisher |
University of Saskatchewan |
publishDate |
2007 |
url |
http://hdl.handle.net/10388/etd-05022007-145956 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Melanitta fusca |
genre_facet |
Melanitta fusca |
op_relation |
http://hdl.handle.net/10388/etd-05022007-145956 TC-SSU-05022007145956 |
_version_ |
1766067579921629184 |