Helmut Kruckenberg

In 1998 we (as a workgroup of University Osnabrück, Germany) started studying ecology and behavior in Greater Whitefronted geese. In the beginning our studies focused on ethology. So we worked intensively on habituational processes in the geese. At first we caught geese only by cannon-netting but then Bart Ebbinge (Alterra) and Prof. Rudi Drent organized to color-mark geese with the goose catchers as well. Within the years a fine working international collaboration was build up and some ten thousand of Whitefronts were color-marked. Traditional goose catching is a proper method to catch high numbers geese on special places. Because a high percentage of the geese is caught together with their partners and siblings, it`s also a valuable method to study especially this: the faith of goose families during the following years. So, we were quite happy to enthusiast goose catchers (mainly Kees) to come to Germany and Hungary for catching as well as helping us and our Russian colleagues a lot in learning how to use such a clap net abroad.

So, over the years together we managed to raise up the percentage of marked birds to a level which allows scientific research with this species. Nowadays approximately 0,5-1% of the population is marked and so analyses of staging duration, exchange rastes of individuals and / or survival rates can be done. For example we analysed to exchange between different parts of Bird Protection Areas of Dollard Region in 2004 or the site fidelity of Whitefronts at the Lower Rhine (literature see http://www.tournatur.de/?94).

In 2006 we started to use satellite transmitters for a more intensive focus into individual migration patterns. Again these birds were caught be Dutch goose catchers. The tracked birds in 2006-2008 were named after the catchers themselves and lots of the birds did it well for some years (http://www.blessgans.de/?tracking). In 2010 most of the birds lost transmitters or were shot. In 2012 together with Max Planck Institute for Ornithology (Radolfszell) we started to use a new generation of transmitters using GPS data and GSM network for transmission. This project is still going on and will continue in the coming years.