Marking behavior of brown bears poses still many unknowns. Green and Mattson (2003) suggest that the rubbing is directly related to marking behavior and that grizzly bears show no discrimination for a specific tree species whereas they do select for larger diameters. In the same study it was found that ecotones and junctions or edges of trails were proposed to be more suitable for marking. Tschanz et al. (1970) presented evidence that bears used rubbed trees for orientation, but concluded that the primary function of rubbing was communication by chemical means. Therefore it seems that rubbing is an important behavior of brown bears to mark their territory and to communicate with females before the mating season. 
Methods:
Signs of bears were investigated during 2007-2010 in northeastern Turkey. The study area is in the southern part of Kaçkar Mountains range and covers 400 km2. The study was conducted on secondary unpaved and dirt roads that connect 12 villages and 10 temporary settlements to Yusufeli town center, and on trails in mountainous rugged terrain. Presence of claw marks, biting, rubbing and height of the marks were investigated. Poles along roads were searched by observers in a car while moving at 15-20 km/h. 860 poles which are either used for electricity or telephone signal transmission were searched between 800 m and 22 00 m altitude. Not only power poles but also rubbing trees were searched during all field work. Ten temporary settlements were reached by walking more than 110 km on trails while searching for bear rubbing trees. Brown bear signs includingrubbing trees, scats, hairs, damaged trees were recorded, photographed and some samples were taken whenever available.
Preliminary Results :
In the study area, 53 poles and 19 trees – especially Scots pines (Pinus sylvestris) – were found to be marked by brown bears. Marking behavior included biting, chewing, rubbing and clawing. Some power poles were found almost broken down due to gnawing. Other poles were only bitten or marked with claws without rubbing if more suitable poles were available within 50 meters. Rubbing trees in Turkey were generally young and with small diameters of 20-40 cm. Marking behavior of male brown bears appears to escalate during late spring. Why some poles were found untouched and others were almost broken is a matter of curiosity even among the locals. Some of them claim only poles covered with tar or bitumen were selected by bears. Others propose that some kind of resonance on poles attracts the bears. The former suggestion sounds more realistic and was further investigated. In Turkey poles erected more than 20 years ago were treated with creosote, a wood preservative, while the more recent ones were not.
Creosote-treated poles exposed to direct sunlight for many years release some tar or bitumen-like blackish sticky substance (Dr. Musa Atar, personal communication), which brown bears are probably attracted to. However creosote is toxic and could thus be possibly harmful to bears. Alternative chemicals containing CCB (Chromated copper bore or arsenate), copper sulfate and sodium dichromate are used also as wood preservatives in power poles (EPA 2007). No CCB-A treated power poles (which can be easily differentiated by their green color) were found to be marked by bears during field work. Sign surveys can help monitor brown bear populations or individuals via genetic studies without need capturing bears and expensive monitoring costs (Karamanlidis et al. 2007). Besides, brown bear marking behavior still needs further investigation to understand its ecology in Turkey.
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