A SPATIAL MODEL OF YELLOW-BILLED CUCKOO BREEDING HABITAT

We are assisting the Lower Colorado River Multi-Species Conservation Program develop a spatial model of Yellow-billed Cuckoo (Coccyzus americanus occidentalis) breeding habitat. Specifically, we are identifying landscape and riparian features that constitute high quality breeding habitat with logistic regression, presence/absence survey data, Landsat imagery and a digital elevation model. Currently, our best candidate model contains three variables and achieves 74% overall accuracy. The most influential predictor variable characterizes terrain ruggedness inside a 1-mile radius, with intermediate ruggedness being the most influential. The second most influential variable characterizes the amount of densest riparian vegetation (NDVI > 0.41) inside a 120-m radius, while the third variable quantifies vegetation heterogeneity within a 480-m radius. The odds ratios indicate that the likelihood of a Yellow-billed Cuckoo occurrence go up significantly as terrain roughness increases, or as the amount of dense vegetation increases within a 120-m radius, or as the heterogeneity of vegetation density increases inside a 480-m radius. The spatial model identifies Yellow-billed Cuckoo breeding habitat remotely and could be used to assess the effectiveness of habitat restoration or enhancement projects.