Effect of Vegetative Cover on Foraging Site Selection by Swainson's Hawk

The Condor ◽  
1982 ◽  
Vol 84 (2) ◽  
pp. 153 ◽  
Author(s):  
Marc J. Bechard
2008 ◽  
Vol 9 (6) ◽  
pp. 779-788 ◽  
Author(s):  
Mark J. Whittingham ◽  
Claire L. Devereux

2016 ◽  
Vol 46 (4) ◽  
pp. 499-507 ◽  
Author(s):  
Daniel M. Geleynse ◽  
Erica Nol ◽  
Dawn M. Burke ◽  
Ken A. Elliott

The Brown Creeper (Certhia americana Bonaparte, 1838) has been identified as one of the most sensitive passerines to partial forest harvest in North America. The effect of selection logging on Brown Creeper density, nest timing, nest survival, and nest and foraging site selection was examined in five silviculture treatments (intensive group selection, typical group selection, old single-tree selection, recent single-tree selection, and control forests) of Algonquin Provincial Park, Canada. As Brown Creeper nests under the bark of large, decaying trees, we hypothesized that Brown Creeper density, timing of breeding, nest survival, and nest and foraging site selection would be negatively affected by silviculture through the removal of large, decaying trees as part of providing safe conditions for loggers. We monitored 101 nests of Brown Creeper during the 2010 and 2011 breeding seasons, mapped territories to estimate density, and conducted foraging surveys. Brown Creeper density was reduced by about 42% in logged stands compared with control stands. Despite that, silviculture did not significantly alter timing of breeding or nest survival. However, the loss of large trees through partial harvesting meant that Brown Creeper nested closer to adjacent, small forested wetlands and often in balsam fir (Abies balsamea (L.) Mill.) in treated stands. In control stands, Brown Creeper nested further from forested wetlands, disproportionately in greater numbers in upland hardwoods, and preferentially in the bark of snags of yellow birch (Betula alleghaniensis Britton). The change in the species of tree used for nesting and the general forest type as a result of logging also resulted in consequences for the selection of foraging substrates. To maintain higher densities of Brown Creeper in logged stands in Algonquin Park, we recommend retaining larger diameter yellow birch, both snags and live trees, preferably within strategically located uncut reserves based on habitat supply planning, that maintains patches roughly the size of Brown Creeper territories (10 ha).


The Condor ◽  
2000 ◽  
Vol 102 (1) ◽  
pp. 211-215 ◽  
Author(s):  
Rebecca J. Safran ◽  
Mark A. Colwell ◽  
Craig R. Isola ◽  
Oriane E. Taft

Abstract We examined foraging site selection by White-faced Ibis (Plegadis chihi) wintering in the Grasslands Ecological Area, which contains the second largest population of nonbreeding ibis in California. We compared habitat variables at White-faced Ibis foraging sites with paired, random locations in managed wetlands of the Grasslands. We contrasted the density and biomass of benthic macroinvertebrates between a subsample of bird foraging locations and random sites. Compared to random locations, the foraging locations of White-faced Ibis were closer to emergent vegetation > 10 cm in height. Moreover, ibis selected foraging locations with significantly higher chironomid and lower oligochaete biomasses relative to random sites. These findings suggest that ibis foraged close to vegetation where prey abundance may be greater and illustrate the importance of maintaining the presence of emergent vegetation in freshwater wetlands.


2002 ◽  
Vol 27 (5) ◽  
pp. 405-412 ◽  
Author(s):  
Richard Shine ◽  
Li-Xin Sun ◽  
Michael Kearney ◽  
Mark Fitzgerald
Keyword(s):  

2011 ◽  
Vol 89 (12) ◽  
pp. 1172-1177 ◽  
Author(s):  
M.L. Goodnow ◽  
L.R. Reitsma

Reproductive success in birds is largely influenced by nest-site selection. Nest predators are the greatest source of nest failure for most species of birds. Species that nest on the ground may be particularly adapted to maximally conceal nests to reduce the risk of loss to predators. Little is known about nest-site selection in the Canada Warbler ( Wilsonia canadensis (L., 1766)), a small ground-nesting Neotropical migrant. We predicted higher amounts of vegetative cover at successful nests of Canada Warblers compared with unsuccessful nests because detection by predators would decrease with greater cover. We measured vegetative characteristics (concealment, stem densities, ground cover) around each nest and compared these variables between successful and unsuccessful nests and between actual nests and mock nest sites on and off territories. Greater concealment and higher stem densities were the main features surrounding a successful nest site. Nest sites had significantly greater concealment when compared with both random mock nest sites on and off territories. Thus, concealment is important for this ground nester and achieved primarily through thick cover and strategic nest placement in vertical substrate with an inconspicuous opening to the nest cup. Forests with complex ground structure and thickets of small-stemmed woody plants should be targets of conservation when considering how to manage this declining species.


Bird Study ◽  
2010 ◽  
Vol 57 (4) ◽  
pp. 531-539 ◽  
Author(s):  
Jenny C. Dunn ◽  
Keith C. Hamer ◽  
Tim G. Benton
Keyword(s):  

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