Bat Diversity


Bats are the second largest group of mammals and the only mammal that is capable of true flight. Contrary to popular belief they are not closely related to rodents but to carnivores, whales, and ungulates. Bats serve as a bioindicator for the health of ecosystems due to their sensitivity to disturbance, pollutants, disease, and climate change. They also perform essential ecosystem services such as insect control, and pollination of native plants and crops. Studies estimated the pest control in the U.S. alone is worth 3.7 to 53 billion dollars a year (

Photo by Amy Fernandez

Why Do We Care?

On Santa Catalina Island there are 10 bat species that occur on island either as residents or as temporary migrants. Three of these species are considered Species of Special Concern by the state of California and are declining on the mainland. Specifically, the Townsend’s big-eared bat and Pallid bat have declined precipitously since the 1940s due to development on the mainland. Fortunately, the 44,000 acres (88%) of Catalina Island owned and managed by the Catalina Island Conservancy is primarily undeveloped natural habitat that serves as a refugia from the development on the mainland.

What We Do

Mist Nets

Mist nets are an active form of monitoring where bats are captured in fine nets. Biologists are then able to determine species, reproductive status and obtain a genetic sample. In July of 2022, wildlife biologists captured in mist-nets juveniles and post-lactating females of Pallid bats and Townsend’s big-eared bat indicating a breeding population for both species. This was the first sighting of a Pallid bat in 87 years. Further monitoring will focus on looking at habitat use by these bats to preserve important resources that the bat populations need to thrive.

Acoustic Detectors

Wildlife biologists on Catalina Island monitor the bat population using 2 primary methods, acoustic detectors, and mist-nets. An acoustic detector is a passive monitoring device that records the calls of bats in an area. Many bat species have a unique call that allows them to be distinguished from other species. The Conservancy currently has 2 long-term, solar-powered acoustic detectors that monitor bats year-round.