Scale-dependent resource selection and space use by Mississippi Kite (Ictinia mississippiensis) in a heterogenous mixed-shrub ecosystem

Abstract

Wildlife use and select habitat at multiple scales, sometimes leading to conflicting interpretations of the importance of various habitat features analyzed at different scales. Species can also exhibit affinities that are unique to portions within their larger distribution. Conservationists need spatially explicit information on habitat use to develop effective management strategies for priority species. This information can be difficult to obtain for species that are highly mobile or occupy large home ranges. In this study, we used a distance sampling approach to estimate multi-scale resource selection for a highly mobile raptor, Mississippi Kite (Ictinia mississippiensis), based on data collected from line transect surveys combined with plotting tools in a geographic information system. We compared land cover of kite detection points to randomly located points at fine and broad spatial scales in a portion of the species’ breeding range in the southern Great Plains, USA. Dominant cover in these landscapes is a mix of grasses, forbs, and expansive stands of a dwarf oak tree (Quercus havardii) generally < 1 m in height. Resource selection in Mississippi Kite was driven by both fine and broad-scale vegetation characteristics. At a fine scale (~ 13 ha), kites selected small, upland forest patches but avoided grass cover and riparian forest. At a broader scale (~ 200 ha), kites avoided oil pads but selected grass cover. Broad-scale selection also favored uplands farther away from riparian forest cover. Both observed density and predicted occurrence suggested riparian avoidance. Avoidance of riparian forest is atypical for Mississippi Kite, but might be explained in this system as avoidance of areas occupied by nest predators of kites, especially Great Horned Owl (Bubo virginianus).