Wildlife timers are an inexpensive alternative to radiotelemetry and camera trapping for assessing activity patterns of vertebrates. We tested the validity of using time-of-capture as an index of species activity periods by comparing wildlife-timer activity data with a concurrent radiotelemetry study of leopard cats (Prionailurus bengalensis) in Thailand. The wildlife timers yielded valid temporal data for a variety of captured vertebrates, although they were prone to mechanical failure in a moist, tropical environment. We recommend sheltering timers from direct rainfall and using silicone sealant to increase timer durability.