The most valuable forests are in the Rodopi, although many of them are interspersed among inaccessible craggy hills. A majority of the country's conifers, both the natural forest and those that have been planted in preference to the slower growing deciduous, are in the higher Rodopi, including the Rila and the Pirin. The most common of the conifers are pine and fir. At elevations beneath those dominated by the conifers, the mixture of broad-leaved deciduous trees is similar to that of the Stara Planina. Of the forest area, only about one-half has tall timber. Scrub on the remainder, however, serves to stabilize the soil of the forest lands against erosion and to slow the runoff of water. The rare and exotic edelweiss can be found on the higher slopes of the Pirin.
The clearing of forestland and the increase in human population have driven most of the larger wildlife from their natural habitats, except in the higher and more rugged terrain. Of the larger species, some bears, wild boars, wild goats, wolves, elk, and several species of deer continue to exist naturally. Foxes, wildcats, polecats, squirrels and other rodents, and hare--better able to adjust to existing conditions--are also surviving.
Quail, turtledoves, wild fowl, and other game birds are hunted in restricted seasons. Hunting seasons are also provided for some of the deer species; the seasons usually last between two and four months, depending upon the need to protect the animal, between the months of August and February. There are bounties on wolves and foxes. Wildcats, falcons, and hawks are also considered harmful and may be killed at any time. The polecat--in Europe the _Mustela putorius_, a fetid-smelling member of the weasel and otter family--is a bloodthirsty, insatiable hunter that terrorizes poultry. It also may be exterminated.
The many caves in limestone-dominated regions have given rise to various types of blind fauna. The largest of them are crabs, but most are insects, including mosquitoes, butterflies, spiders, locusts, and common flies. Although they are blind, exposure to light is usually fatal to such species.
Rivers contain several kinds of freshwater fish, the most plentiful of which are sturgeon, whitefish, and European carp. Mackerel account for the largest percentage of fish taken from the Black Sea. There are no sharks or other dangerous fish in these waters, but a rare Black Sea seal breeds along the rocky coast north of Varna.