Autumn roost site selection by the Common Crane Grus grus in the Hortobágy National Park, Hungary, between 1995–2000

Abstract

One of the largest migration routes of the Common Crane Grus grus leads across the Hortobágy National Park in Hungary, where more than 60 thousand cranes - a considerable part of the European (mostly Finnish) breeding population - stage for more than two months. The aim of this study was to investigate factors that may attract the Common Crane to roost sites in the Hortobágy and the surrounding non-protected areas of Eastern Hungary during the autumn migrations from 1995 to 2000. We found that two types of wetlands were used by cranes for roosting: drained fishponds with shallow water, and shallow marshes with open stretches of water. Most cranes were observed between mid October and early November (31 600-64 000 birds). The cranes selected 23.8% of all possible roost sites. Although 84% of marshlands were selected, and only 2.9% of fishponds drained at least once during the investigation were chosen for roosting, 74.5-79.4% of the total population roosted in a single drained fishpond. The peak number of roosting cranes correlated positively with the size of roost site, its distance from human settlements and roads. The effect of the distance between feeding and roosting sites was significant (negatively) only when differentiating between roost sites used only for one year and roost sites used for several years. Although the Common Crane preferred drained fishponds to marshes over the whole area, marshes and drained fishponds were equally selected in protected areas. We suggest that all important roost sites should be protected, wildfowl hunting should not be permitted and fishing activities should be reduced in wetlands suitable for roosting during migration.