LE3 .A278 2007

2007

Taylor, Phil
Shutler, Dave

Acadia University

Master of Science

Masters

Biology

Biology

Animal populations can fluctuate depending on fluctuations at multiple scales in habitat availability and habitat structure. Using nest-monitoring and passive mist-netting, I examined the importance of habitat composition at nest-site (5 m), local (20 m), neighbourhood (115 m), and landscape (1250 m) scales, in relation to breeding success of boreal birds. At the scale of the nest-site, each of three species ('Dendroica coronata, Dendroica striata,' and 'Zonotrichia albicollis') non-randomly situated their nests in terms of structural vegetation variables. However, none of the structural variables that distinguished nest-sites from random sites were important predictors of overall nest success or nest predation. When focusing only on nest-sites, neither of the 'Dendroica' species had structural vegetation variables associated with nest success. However, successful 'Zonotrichia albicollis' nests were associated with less canopy cover and woody debris than unsuccessful nests. At local, neighbourhood, and landscape scales, several trends were observed between habitat composition (proportion of clear-cut) and breeding success. First, habitat composition at broader landscape scales became more important to breeding birds as the breeding period progressed. Second, spatial and temporal heterogeneities interacted to make breeding success difficult to predict. Third, influences of habitat composition differed depending on the species, but forest-nesting specialists were more negatively influenced by increased proportions of clear-cut in the surrounding area.

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https://scholar.acadiau.ca/islandora/object/theses:3032