The Otter (Lutra lutra L.) Signs and the Banks Tree Cover: A Survey in Central and Eastern Bulgaria

The study was carried out during 2011 – 2012 at different water basins (rivers and micro dams) situated in Central and Eastern Bulgaria. Transects with 600 m length were walked along the banks in otter signs search. The search was stopped when the first otter signs were registered. As a whole we found domination of the very good or excellent bank tree cover. A total of 61% of transects were with tree cover between 50% and 100%. Almost equal were the stretches without or with little tree vegetation. At all transects surveyed the spraints dominated with 61%. All other otter signs were with low percentage. The otter tracks (foot prints) were on second place with 20% of occurrence, followed by the food remains with 7%. At 12% of transects we did not find any otter signs. As a whole the otter was registered in 88% of transects, a sign for a good population. Highest preference we registered for walking or feeding of the otter at the open banks with no or with weak tree cover.