Jasja works as an independent ecological researcher, but in the Bats and Climate Change: from Science to Conservation Cost Action he represents the Dutch Mammal Society. He currently works for this organisation updating the national review of the conservation status of mammals for the new Dutch Red List. Jasja likes combining classical biology (binoculars and notebook) with modern techniques (such as GPS-loggers, camera traps, stationaire ultrasound loggers and novel statistical tools) to tackle questions from nature management and policy. Most of his research focuses on mammals and species that eats them (such as owls and raptors). Until the end of his term in 2020, Jasja is chair of BatLife Europe. Site of Dutch Mammal Society: www.zoogdiervereniging.nl