Nest site selection of the Eurasian Crane Grus grus in Estonia: an analysis of nest record cards

Abstract

We describe in detail the nesting habitats of the Eurasian Crane in Estonia and explore relationships between different habitat characteristics and nesting success. We analysed all 161 reported Eurasian Crane nest finds in Estonia. We found that the cranes favorite nesting habitats are different types of mire (71% of all nests), especially fens (44%). We conclude that, despite the fact that the Eurasian Crane breeds in different habitats, nesting sites include the same or similar structural elements (vegetation types, plant species and communities and elements of micro-relief). We found that the date of the beginning of egg laying is significantly related to the size of the nesting habitat and that the annual mean date of the beginning of egg laying in Estonia has advanced considerably during the period 1901 to 2001. We also discovered a significant relation between the distance of neighbouring nests (population density) and the brood size and a negative effect of human activity on nesting success.