It is only an active approach to the protection of a threatened species that may ensure its survival in the long run. An active protection implies implementation of management plans. The formulation of these plans requires determination of main factors affecting the trends in the number of the threatened population and understanding of interrelations and the dynamics. Therefore it is necessary to become familiar with essential facts about the biology of the wolf population and its impact on human life in the same space.
It is also necessary to study the characteristics of those human activities that have the major impact on the dynamics of the wolf population. This stock of knowledge is then used in formulation of the wolf management plan and in making decisions on the management of this, in Croatia , protected species.

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As a result of many centuries during which wolves were pursued and killed by man in order to be totally exterminated, the wolves of today have become very cautious and hardly noticeable. The studies must therefore resort to indirect methods of data collection through indications of the wolf's presence and passing (traces, excrements, prey rests). Most of the data on the wolf's movement, habitat use and activities may be collected by telemetric monitoring. This method of studying the wildlife consists of capturing individuals alive and their subsequent release in the wild after marking them in one or more ways to facilitate monitoring of their movement and natural behaviour.
The most appropriate and proven method of marking the wolves so as to be able to study their biology is radio-collaring. A portable radio-receiver and an antenna are used to detect a signal which enables determination of the location and activity of the animal monitored. Since not long ago these collars for monitoring are equipped with a GPS device and a GSM addition sending data by SMS directly to the researcher's computer.

The data on wolf mortality in Croatia , especially in Gorski kotar, were collected and analysed by Alojzije Frković , Eng. Information that he had collected were of crucial importance for recognizing threats to wolf populations in Croatia before they were protected in 1995. A systematic study of wolves in Croatia started late in 1996 within the framework of a research project entitled "Carnivores of Croatia" run by Prof. Dr. Đuro Huber, while the project section dealing with wolves is run by Dr. Josip Kusak, both from the Department for Biology at the School of Veterinary Medicine of the University of Zagreb. Since the end of 2002 the studies have been carried out within the LIFE project "Conservation and Management of Wolves in Croatia ".

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After the wolf was designated protected in 1995 and payment of compensations for damages caused by wolves to the livestock were launched, most of the claims for damages were received from Dalmatinska zagora. It was therefore highly important to find out why it is there of all the places that most of the wolves' attacks on the livestock occurred and which circumstances are favourable to occurrence of damages caused by wolves.

From 1998 to 2000 three wolves from two neighbouring packs in the area beyond Kaštela were telemetrically monitored.

The female W1-Pepa belonged to the young of the Opor pack from the 1998 litter. The pack dwelled in the Opor, Praća, Ljubeč and Trištenica mountains. The female was monitored for a total of 643 days. On becoming fully grown she left the parents' pack and moved to the Moseć mountain where she disappeared without trace.

The female W2-Anja was a reproductive female from the Vučevica pack. The pack dwelled most of the time in the densely overgrown and uninhabited Vučevica valley divided from Split and Kaštela by the Kozjak mountain only. Anja was monitored for a total of 699 days, after which the signal coming from her collar disappeared.

The wolf-cub named Berni was a cub of the female Anja, the litter of 2000. He was monitored for a relatively short period of time, because only 33 days after collaring he was found dead on the hill above the Jurići village. The examination and dissection carried out at the School of Veterinary Medicine showed that he had been shot.

After the 3 years of studying we knew much more about wolves in Dalmatinska zagora than about those inhabiting other parts of Croatia . The basic facts established about wolves in Dalmatia are:

•  The average size of the territory (150.5 km 2 ) covered by two packs monitored in Dalmatia fits into the range of territory sizes needed for the establishment of a wolf population and for populations preying mainly on deer.

•  Human activities (hunting and livestock grazing) affected the choice of space used by the telemetrically monitored she-wolf in various seasons.

•  The average distance covered daily by telemetrically monitored wolves was 2.5 km.

•  The females monitored dwelled mostly on northern sides of the mountains or in the valley.

•  The females monitored spent most of the time (82.9 per cent of the locations) secluded in degraded, thick forest segments of oriental hornbeams or segments of pubescent oak and oriental hornbeam with the average density (seclusion from the view) of 97.2 per cent.

•  The average distance of wolves monitored from the nearest house (683 m) was considerably larger (p=0.031) than the distance (563) from random locations.

•  The average distance of the monitored wolves from the nearest water spring (921.5 m) was considerably smaller (p=0.024) than the distance (1,074 m) from random locations.

Owing to favourable habitat conditions the highland area of Croatia has been and has remained the core area in which wolves succeeded in surviving permanently and, as the conditions improved, spread to adjacent areas. From 2002 to 2004 six wolves from two neighbouring packs were captured and radio-collared.

The first wolf was captured and collared at the foot of the Guslica hill on 21 June 2002. It was a female called Ines, aged 2, very thin at the moment of capturing - weighing only 21 kg. She belonged to the Snježnik pack that she left during the winter 2002/2003. That same winter she entered the territory of a pack living on the Platak. These wolves found her, killed and ate her up.

The second wolf was captured under the Šija hill on 2 July 2002. It was also a female, who was named Hilda. She was three years old and weighed 24 kg. Her pack was named Risnjak.

The third wolf monitored belonged also to the Risnjak pack and was collared on 23.10.2002. It was another female, the current year's cub called Blaža, at the moment of capturing seven months old and weighing 20 kg.

The fourth wolf (a young W8-Felix) was a cub of the female Hilda. On 25.08.2004 he weighed 14.5 kg and was replacing the milk teeth with the permanent ones. Hilda left the Risnjak pack in spring 2003 and became a reproductive female of the Snježnik pack. So both of the wolves were members of the Snježnik pack.

The fifth wolf was a female aged 2.5 and weighing 25 kg when captured. This female was named W9-Mila and collared by GPS-GSM. The first monitoring results pointed to her belonging to the Platak pack. Later it proved, however, that at that time of her life Mila did not belong to any of the packs, but was alone and in search for a living space and partner.

The sixth wolf is a reproductive female (alpha female) of the Risnjak pack named W10-Tanja, which means that the wolves Hilda and Blaža are her immediate descendants and the cub Felix her grandson. This will hopefully be confirmed by genetic analyses.

The Risnjak pack spends most of the time in the area between Crni Lug, Delnice and Lokve, but crosses also to the other side of the Risnjak mountain - up to the Lazac meadow, Vilje, Suha Rečina and Gornje Jelenje, which is an area of 120 km 2 . In the summer of 2002 the Risnjak pack numbered six wolves, but during the winter 2002/2003 this number dropped to four. At the beginning of the winter 2004/2004 the Risnjak pack numbers at least five wolves.

The Snježnik pack dwells to the northwest of the local road, above the settlements Gerovo - Tršće - Prezid. Their territory does not include any settlement and covers about 80 km 2 . In the summer of 2002 the pack consisted of at least four wolves, but during the winter 2002/2003 this number fell to two or maybe just one wolf - a large male. In the spring of 2003 the female Hilda left the parents' pack of Risnjak and joined the remaining member of the Snježnik pack. In 2004 this pair of wolves had a litter of cubs, with Felix being one of them.

From the moment of being collared till the end of 2004 Mila moved over an area of as much as 940 km 2 , which is eight times the size of the known territories of wolves in Croatia . During that period she did not belong to any pack, but was looking for a partner and living space. In doing this she entered and crossed the territories of foreign packs, exposing herself to the risk of being discovered and killed by them. It is more likely that she will be killed than that she will manage to establish her own pack.

The wolves of Gorski kotar are very active during the day too, because the forest vegetation provides sufficient protection. Unlike them, the wolves in Dalmatinska zagora are chiefly active during the night.

By following their traces in the snow and analysing the DNA from the wolves' excrements we found out that the packs in this part of Gorski kotar number 2 - 6 individuals. This means that in three packs the number of individuals ranges from 10 to 15 wolves at most. The number of wolves is variable. Young wolves are born in spring, some get killed as cubs already and some succeed in reaching the age of leaving the parents' pack. The majority gets killed in the period when they leave their pack. Only some of them reach the sexual maturity and still a smaller number gets a chance to multiply.

The wolves of Gorski kotar lose their life due to natural causes and humans. The she-wolf Ines was killed when she left her pack and entered the territory of the Snježnik pack. These wolves found her, killed and ate her up. Under the natural conditions, without any human impact, this is the most natural way in which a wolf's life can end. The cub Felix died of a disease and the female Blaža was shot by humans. She was found on the borderline between the Risnjak National park and one of the hunting grounds that surround it.

Author: Dr. Josip Kusak, Department of Biology at the Veterinary faculty of the University of Zagreb, Croatia

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