Knowledge of roosting and foraging requirements is necessary in managing for viable bat populations, especially when areas are being cleared of native vegetation for development, such as solar installations, infrastructure, agriculture, and urban expansion. Bats are very mobile and often active in areas not accessible by roads.  Nocturnal aerial tracking from a light aircraft has been successful in determining foraging habitat and the minimum distance traveled for three species of bats: California leaf-nosed bat (Macrotus californicus), Townsend’s big-eared bat (Corynorhinus townsendii) and Allen’s big-eared bat (Idionycteris phyllotis). Macrotus was tracked from three different mine roosts along the Lower Colorado River in winter and summer 2015-16 and exhibited different seasonal activity and foraging behavior. In a summer roost in the same area in 2016, Corynorhinus used the same foraging habitat as Macrotus, with both species traveling a minimum of 40 km/night. In 2004, Idionycteris in Arizona traveled approximately 80 km roundtrip nightly between the roost in creosote bush scrub at 1000 m elevation and foraging areas in mesquite grassland and pinyon/juniper woodland (1500-2000 m) in the next mountain range to the east.  Protecting a limited radius of habitats near the roost for foraging would not have been appropriate for these bat species.

For 55 years Patricia Brown has been conducting research on bats in the southwestern U.S. and elsewhere in the world. She received her doctorate in Biology from UCLA in 1973, and since then has continued research on bats as a Research Associate at UCLA and a consultant to government agencies and private entities. She has studied bat hearing, echolocation, ontogeny, ecology, foraging and roosting behavior, with a special interest in bats roosting in mines and their conservation. As an advocate for bat conservation, she is a member of the Western, Nevada and California Bat Working groups.