TESTING ADAPATIVE HABITAT SELECTION IN BREEDING SWAINSON'S HAWKS

Elizabeth D Meisman; Cal Poly Humboldt; edm170@humboldt.edu; Christopher Vennum, Ho Yi Wann, Jeffrey Dunk, Christopher Briggs, Peter Bloom, Michael Collopy, Brian Woodbridge, Matthew Johnson

The theory of adaptive habitat selection posits that individuals preferentially select habitats that maximize or improve their fitness, though various behavioral or environmental constraints can result in mismatches between habitat quality and selection. In long-lived territorial species like Swainson’s Hawks (Buteo swainsoni), these mismatches may pose serious risk to population viability. One of the longest running raptor studies in North America has tracked breeding in a population of Swainson’s Hawks in Butte Valley, California over the past 45 years (1979-present). Swainson’s Hawks exhibit strong site fidelity to territories on their breeding grounds. Thus, this long-term dataset is ideal to test whether adaptive habitat selection is operating as habitat conditions have changed over time. I will create generalized linear models to assess nesting territory selection, nesting success, and productivity (measures of habitat quality) over time and as a function of varying land cover compositions (alfalfa, cereal grains, row crop, grassland, juniper, and bare dirt). I will present results of resource selection functions examining nesting territory selection at multiple spatial scales. This information may have implications for understanding how the Butte Valley Swainson’s Hawk population may respond to future changes in land use.

Wildlife and Agriculture II