Ornis Hungarica. vol.11. (2001) p.9-18.
Habitat selection of Corncrakes (Crex crex L.) in Szatmr-Bereg (Hungary) and implications for further monitoring
In 1997 we carried out a survey of the corncrake in Szatmr-Bereg in eastern Hungary in an area covering 1170 km2 and containing 137 km2 of natural grassland. To study corncrake habitat preferences, we compared habitat factors of 17 clearly delimited grassland sites with at least two singing corncrakes with the respectively closest grassland sites of similar size where no corncrakes occurred. We assessed the area of the site, measured vegetation height and density, wet standing crop, an index of humidity and an index of habitat structure and recorded land-use at each site. Corncrake habitats were more productive, more humid and showed more additional structures than grasslands without corncrakes. Concerning land-use, corncrake habitats contained more currently abandoned parts (set-asides) and less intensively grazed parts than non-corncrake habitats. In a logistic regression model, vegetation height, vegetation density and the index of structure were selected as the variables with the largest explanatory power for the presence/absence of corncrakes. We suggest that these indices should be used as tools to monitor changes in corncrake habitat at a large scale.