RESEARCH ARTICLE Multi-scale predictive habitat suitability modeling based on hierarchically delineated patches: an example for yellow-billed cuckoos nesting in riparian forests, California, USA Evan H. Girvetz Æ Steven E. Greco Received: 23 June 2008 / Accepted: 22 June 2009 Ó Springer Science+Business Media B.V. 2009 Abstract The discipline of landscape ecology rec- ognizes the importance of measuring habitat suitabil- ity variables at spatial scales relevant to specific organisms. This paper uses a novel multi-scale hierarchical patch delineation method, PatchMorph, to measure landscape patch characteristics at two distinct spatial scales and statistically relate them to the presence of state-listed endangered yellow-billed cuckoos (Coccyzus americanus occidentalis) nesting in forest patches along the Sacramento River, Cali- fornia, USA. The landscape patch characteristics calculated were: patch thickness, area of cottonwood forest, area of riparian scrub, area of other mixed riparian forest, and total patch area. A third, regional spatial variable, delineating the north and south portions of study area was also analyzed for the effect of regional processes. Using field surveys, the landscape characteristics were related to patch occu- pancy by yellow-billed cuckoos. The area of cotton- wood forest measured at the finest spatial scale of patches was found to be the most important factor determining yellow-billed cuckoo presence in the forest patches, while no patch characteristics at the larger scale of habitat patches were important. The regional spatial variable was important in two of the three analysis techniques. Model validation using an independent data set of surveys (conducted 1987– 1990) found 76–82% model accuracy for all the statistical techniques used. Our results show that the spatial scale at which habitat characteristics are measured influences the suitability of forest patches. This multi-scale patch and model selection approach to habitat suitability analysis can readily be general- ized for use with other organisms and systems. Keywords Geographic information systems (GIS)  Spatial analysis  Landscape ecology  Riparian ecosystems  PatchMorph Introduction The science of habitat suitability modeling has evolved from simple expert opinion models (Verner et al. 1986), to more complex multi-scale and statistically based models (Scott et al. 2002). Deter- mining the relevant spatial scale to measure habitat characteristics has become important for modeling species habitat needs at the landscape level (Scott et al. 2002). Habitat features must be measured at spatial and temporal scales which are relevant to the organism or ecological process being modeled, E. H. Girvetz  S. E. Greco Department of Environmental Design, University of California, One Shields Avenue, Davis, CA 95616, USA E. H. Girvetz (&) School of Forest Resources, University of Washington, Box 352100, Seattle, WA 98195, USA e-mail: givetz@u.washington.edu 123 Landscape Ecol DOI 10.1007/s10980-009-9384-2