Description of the winter habitat of grassland birds with remote sensors and visual estimation

Abstract

Understanding habitat preferences of grassland birds declining is important for their conservation. Currently, the use of remote sensing technology to describe the habitat of grassland birds is a novel tool in Mexico which may allow for more accurate assessments of grassland habitat. High-resolution photographs and a protocol established by Bird Conservancy of the Rockies that uses ocular estimation was used in order to estimate vegetation cover within areas where individual sparrows of the genus Ammodramus were recorded in two sites located in Durango. Forty location points were randomly selected from detections (n = 1881) recorded from the follow-up of 33 individuals of A. bairdii and 23 of A. savannarum, by telemetry. Vegetation metric was obtained and from high-resolution photographs we created an orthomosaic with supervised classification in 4 classes of vegetation cover (%). At each bird location point, the percentage of each vegetation cover class within a 5 m radius area around the point was estimated. We did not find a significant difference between vegetation cover obtained by a high-resolution photographs or ocular estimations (p≤0.05) by species. Both species were found in areas with grass cover similar to those reported using different methods (61.24±4.07%, 62.78±4.24%). These results indicate that the use of remote sensing provide favorable information for the characterization of grassland bird’s habitat.