Tracking migratory movements of birds between breeding and wintering areas is important for both theoretical and conservation purposes. In particular, information about linkages between stages of the annual cycle (i.e., migratory connectivity) is essential for identifying factors and processes limiting population sizes of birds. Further, this information is necessary for testing assumptions and hypotheses about the evolution of avian migratory patterns. Here, I used stable hydrogen isotope (δD) analyses of tissues representing different periods and geographic regions of the annual cycle of white-throated sparrows, Zonotrichia albicollis, to provide new information on spatial and temporal linkages between stages of the annual cycle of this species. To achieve this objective, I sampled white-throated sparrows during spring and fall migration of 2002 and 2003 at a key staging ground for North American migratory birds located at Delta Marsh, Manitoba.
Based on evaluations of the correspondence between δD values of feathers, claws, and cellular portions of blood of migrants, I determined that δD values of claws and blood cells were not suitable for estimating wintering origins of individuals captured en route to breeding areas. However, δD values of head feathers grown on wintering areas and tail feathers grown on breeding areas corresponded to values expected for feathers grown in broad areas within the wintering and breeding range of the species, respectively. The δD values of feathers showed no relationship between estimated breeding or natal and wintering latitudes of white-throated sparrows. However, band-encounter analyses indicated a clear eastwest segregation of populations across Canada, a finding that suggests that this species has a parallel migration system. Temporally, all components of the breeding populations migrated together during spring migration. However, as expected, white-throated sparrows exhibited sex-biased differential timing of spring arrival and latitude of wintering origin. Consistent with several other differential migrants, female white-throated sparrows arrived later and originated from more southern latitudes. There was also a negative relationship between wintering latitude and arrival dates of individuals during the second spring of the study. The existence of this relationship is a key assumption of differential migration hypotheses that had not been previously validated. Furthermore, since timing of arrival at breeding areas is critical to establishing high-quality territories and pair bonds, relationships between wintering latitude and arrival date of individuals could have important carry-over effects to reproduction. Based on standard body condition indices, white-throated sparrows migrating longer distances to reach breeding areas were not in poorer body condition than those migrating shorter distances. Thus, the cost of migrating longer distances does not appear to affect pre-breeding body condition, a parameter known to be linked with reproductive success.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-08122005-101930 |
| Date | 15 August 2005 |
| Creators | Mazerolle, Daniel Freddy |
| Contributors | Wolf, Blair, Wilson, Kenneth E., Marchant, Tracy A., Hobson, Keith A., Clark, Robert G., Bollinger, Trent K. |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-08122005-101930/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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