The reproductive performance of Sharp-shinned Hawks (Accipiter striatus) nesting in southern Quebec was studied during the 1999 and 2000 breeding seasons. In 2000, 37.5% of breeders (equal numbers of males and females) were immature, whereas none were in 1999. In 2000, clutch size and hatching success were 4.4 and 3.1 eggs per nest, respectively. Of 10 pairs monitored in 2000, six hatched at least one chick and five raised young to a bandable age. However, only three pairs successfully fledged at least one young that year, whereas all seven nests observed in 1999 did so. Unseasonable weather in 2000 may have contributed to this decrease in nesting success. / In 2000, levels of organochlorines were measured in blood samples taken from sharpshin females and their young at five of the above-mentioned 10 nests. While most compounds were not detected at all, or at least not at levels likely to affect reproduction, concentrations of DDE and PCB's in these breeding females were much higher than in female migrants previously sampled in the eastern United States or Great Lakes. Whereas global contamination of the environment appears to be the source of PCB exposure, this population may be accumulating DDE on its wintering grounds. / Habitat assessments were conducted at 12 sharpshin nests over both years of the study. Means of the variables measured (among others) were nest tree height, 15.3 m; tree density, 1052/ha; total canopy cover, 86.7%; coniferous cover, 42.95%; and distance to the nearest opening, 17.5 m. Nests were found in a range of forested habitats, but this population did not exhibit a noteworthy degree of plasticity with respect to the measured parameters. That these sharpshins tended to use structurally older stands with more deciduous cover than other populations did may reflect regional differences in habitat availability and/or in the abundance of competitors.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.33735 |
| Date | January 2001 |
| Creators | Coleman, Joanna L. |
| Contributors | Bird, David M. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Natural Resource Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001872483, proquestno: MQ78852, Theses scanned by UMI/ProQuest. |
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