Resource configuration and abundance affect space use of a cooperatively breeding resident bird
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The Auk. 131(3): 407-420.
Movement and space use of birds is driven by activities associated with acquiring and maintaining access to critical resources. Thus, the spatial configuration of resources within home ranges should influence bird movements, and resource values should be relative to their locations. We radio-tracked 22 Brown-headed Nuthatches (Sitta pusilla) and related their space use and home range sizes to available resources while taking nest site locations into account. We developed utilization distributions (UDs) from nuthatch locations, and treated the area of each 95% isopleth as home range size and the height of the UD as relative probability of use. We fit models relating home range size to mean resource measures within home ranges, and used lognormal regression to relate intensity of use to resource metrics at random points by ranking linear mixed models. Nuthatch home ranges typically had two centers of activity. Areas of high use were associated with the density of recently killed snags (likely a foraging resource), recent prescribed fire, pine dominance, low tree stocking rates, and grassy herbaceous cover. Home ranges were generally large (median: 7.1 ha; range: 0.3-47.6 ha), and smaller home range sizes were associated with pine dominance and higher nest snag density. Predicted home range sizes decreased by 77% and 69%, respectively, when percent pine and nest snag density were maximized. Our results illustrate that movement decisions within home ranges are driven by both the availability and spatial distribution of resources, while ongoing savannah-woodland management is providing resources that are used by Brown-headed Nuthatches.
Keywordshome range size optimal foraging theory resource selection Sitta pusilla utilization distributions
Stanton, Richard A.; Kesler, Dylan C.; Thompson III, Frank R. 2014. Resource configuration and abundance affect space use of a cooperatively breeding resident bird. The Auk. 131(3): 407-420. https://doi.org/10.1642/AUK-13-186.1.