The plains of northeastern Ukraine are alive with bats during the summer months. But for wintertime, the landscape offers no natural caves or abandoned underground mines where non-migratory species can hibernate. Where, then, are these bats spending their winters.
Anton Vlaschenko, a graduate student at Kharkov National University in Ukraine, decided to find out, with the help of a Bat Conservation International Student Research Scholarship. His preliminary data suggested that bats that don’t migrate and lack access to caves likely used rock crevices for hibernating. He had previously identified an abandoned open-pit mine near the village of Zavody where several species of bats lived year-round. More than 1,000 of them hibernated in deep crevices in the walls of the pit.
Few bat researchers had studied the region and Vlaschenko cites an almost complete absence of data on the characteristics, locations and abundance of suitable crevices. So Vlaschenko and his field team set out to survey likely sites and identify their conservation needs. He and his team searched 385 square miles (1,000 square kilometers) for other hibernation sites, such as natural crevices and open-pit mines.
Sixty days of hiking, climbing and mist-netting revealed no sites that contained hibernating bats or evidence of past use. That left only the Zavody Open Pit, where the main crevice roost was about eight feet (2.5 meters) high and averaged some 2.75 inches (7 centimeters) wide.
Netting at the site (between March and November over several years) produced more than 900 bats of 10 species, five of them migratory and captured only in August. These migrating bats apparently use the open pit as a stopping point in their journey. The other five species are permanent residents, although their relative abundance varies through the year.
Vlaschenko continues to analyze his data, and additional study is needed to confirm the scarcity of suitable hibernation-crevices. But Vlaschenko said his “main conclusion is that the (Zavody) Open Pit is a unique place for bats in all Ukraine,” a site that’s crucial for both resident and migratory species. The crevices are threatened by water flow and human disturbance, and the site must be protected from renewed mining. “We are,” he said, “compiling the documents for creation of a little bat reserve in the Open Pit.”