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Wolf tracking in Gorski kotar - Croatia

Department of Biology at the Veterinary faculty
of the University of Zagreb, Croatia

by Josip Kusak


last update: February 14, 2005

The most reliable data on wolf movements, habitat use and activity in densely forested areas, where animals can not be visually observed, can be obtained by the use of telemetry. Traditionally, this method comprised of capturing and radio-tagging of animals, which then can be tracked from the distance by the use of radio receiver and directional antenna. This method requires that the researcher must be present in the field for every bit of data collected. A new GPS collars can collect data even during the time when the researcher is not in the filed.


Radio-telemetry of wolves in Gorski kotar – northern part of wolf range in Croatia, began in 2002. The purpose of the study is to obtain basic data on wolf biology, which is necessary for the management of this, in Croatia, protected species.








A total of 6 wolves was captured and radio-collared until the end of 2004. Five of them belonged to two neighboring packs (Risnjak pack and Snježnik pack), and one wolf was captured while on dispersal (as concluded by later tracking).

The dispersing wolf was a female, 25 kg, in third year of her life. It was captured on 11.09.2004, was named Mila, and equipped with GPS-GSM collar (fig. 1)


Fig. 1: Wolf Mila with a
GPS GSM collar












The origin of Mila wolf in not yet known - we are waiting for the results of genetic analyses. Mila was captured in the middle of Snježnik pack territory, and our first assumption was that she belongs to this pack. The day after the capture she started to move toward south, in two days she was far away of Snježnik pack territory, on slopes facing Adriatic sea (fig. 2).


Fig. 2: Movements of wolf  “Mila”, September 12- December 12, 2004


During the Summer several flocks of sheep were grazing there. She stayed there for a week, and we started to think that Mila wolf belongs to third pack in the area, to the Platak pack. Then she surprised us again! During one day she moved 30 km to southeast, and emerged in totally different area. For this move she had to cross the highway. This was not a problem because 25% of the highway is either in the tunnel or on the viaduct. After few days she was back to coastal slopes, but this saw not all. Later she crossed the territory of another pack, Risnjak pack, and visited the source of Kupa river. After that Mila wolf was found staying in the area where the territories of two tracked packs overlap. Until recent times Mila wolf continued to wander around, inside and outside of known wolf territories.

Wolves are known for their swift travels when they roam their territories. Dispersing wolves travel even more, and are real nightmare for those who have to track them from the ground (believe me – I was doing this for years). GPS-GSM collars are ideal for such situations, giving large amount of accurate data which would never be collected with the use of classical VHF radio-collars. I still go to the field, there are other wolves with VHF collars, wolves without any collars, and many things to find out about them.


For more information please contact:







Dr. Josip Kusak  josip.kusak@zg.htnet.hr


Prof. Dr. Ðuro Huber, Croatia,  Projectleader


Links: http://www.vef.hr/org/biologija/index.htm