Predicting the distribution of raptors using remote sensing techniques and Geographic Information Systems: A case study with the Eastern New Zealand falcon (Falco novaeseelandiae)

Abstract

Remote sensing and Geographic Information System techniques were used to predict the distribution of nest site habitats of Eastern New Zealand falcons (Falco novaeseelandiae) in Otago. Satellite imagery (SPOT 4) was used to produce a vegetation map, which was integrated into a GIS database with contour, stream, road, and house data extracted from digital topographical maps. Habitat selection criteria were analysed comparing habitat features in the vicinity of nest sites with those available within the study area. Habitat selection criteria, including vegetation type, aspect, elevation, slope, terrain steepness, distance to water and human influence, were combined to build a model predicting the potential distribution of falcon nests. Our evaluation of the model showed that Eastern New Zealand falcons do select nesting territories in areas predicted by the model to be suitable breeding habitat. This technique has the potential to facilitate the location of falcon breeding sites, to allow more accurate estimates of the distribution, extent, and status of nesting habitat of New Zealand falcons, and could help to estimate the total population size and thereby enable more rigorous evaluation of the threat status of the species.