Abstract
This paper explores the relation between the local numbers and distribution of autumn staging Eurasian Cranes (Grus grus Linn.) and agricultural land use during recent decades in Estonia. The analysis is based on the long-term monitoring data of staging cranes and the statistical data of land use in Estonia. We found that great changes in cropping area, as well as in crane numbers have taken place in Estonia since the 1960s. We also found a significant positive correlation between crane numbers and the cropping area of summer wheat, winter wheat, winter rye and all cereals together, and a negative correlation with the area of potatoes. Generally, arable land, particularly that used for growing cereals, has a great influence on the local numbers and distribution of staging cranes. Based on our findings, we predict that changes in the local numbers and distribution of Eurasian Cranes staging during their migration in Estonia and elsewhere will depend on changes in agricultural land use in staging areas, rather than on the size of the breeding population. As about 10 percent of the European Eurasian Crane population stop over in Estonia during the autumn migration, the country has an important role to play in the protection of the species.;
Highlights
The Eurasian Crane is distributed in Eurasia from latitude 69°N to latitude 40°N and from longitude6°E to longitude 165°E (Cramp and Simmons 1980, Prange 1989, Meine and Archibald 1996)
We found that the total numbers of Eurasian Cranes staging in Estonia during the autumn migration rose rapidly in the 1960s and 1970s, and stabilized in the
On the basis of colour banding and radio tracking we know only that cranes from the local population and from Finland are mixed in Estonia during the autumn migration (Lundin 2005, Leito et al 2006)
Summary
6°E to longitude 165°E (Cramp and Simmons 1980, Prange 1989, Meine and Archibald 1996). Breeding populations have increased across most of Europe. In Estonia the breeding population of the Eurasian. Eurasian Cranes are omnivores, mostly feeding carnivorously during breeding and herbivorously during the migration and wintering periods (Cramp and Simmons 1980, Prange 1989, Díaz et al 1996, Avilés et al 2002). The composition of their diet depends on the season and local foraging opportunities. In Estonia, the main feeding habitats for cranes in the autumn are fields of different cereals and mowed grasslands (Leito et al 2006)
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