On a night walk in Wanneroo, a smartphone-linked detector picked up calls from bats most people would never hear. The device turned their high-pitched signals into recordings, giving volunteers a way to spot animals that are small, swift and active after dark.
That matters because bats can be hard to study and easy to overlook. They spend much of the day in tree hollows, caves and other hidden roosts, then emerge at night to hunt or feed. Insect-eating bats help control insect populations, while flying foxes pollinate native plants and spread seeds. Yet many people rarely see bats up close, and misconceptions about them can persist.
Researchers first reviewed 51 published studies of bat citizen science projects from around the world. They found that acoustic surveys, which use ultrasonic detectors to record bats in flight, were the most common method. But few studies had looked closely at what volunteers gained from taking part. The team set out to explore both questions: whether local residents could help gather useful information, and whether the experience changed how they thought about bats.
In 2025, the researchers invited residents of the City of Wanneroo, in Perth, Western Australia, to join a bat-finding project. Volunteers were recruited through social media and local environmental and citizen science networks. After training in how to use smartphone-connected detectors and how to recognize local species, they split into small groups and walked set routes through nearby bushland.
Across 23 surveys, volunteers recorded five bat species. Gould's wattled bat (Chalinolobus gouldii) was the most common, suggesting it is well suited to urban surroundings. The group also detected Holt's long-eared bat (Nyctophilus holtorum) within the City of Wanneroo for the first time. They did not record chocolate wattled bats (Chalinolobus morio) at the urban survey sites.
The recordings add detail to the picture of which bats are using Perth's urban landscapes. They also point to questions for future research, including why some species seem more able than others to live near people. A species not found during these surveys may still be present elsewhere; the results describe what volunteers recorded at the locations they covered.
The project also measured what happened for the people taking part. Participants filled out questionnaires before training, just after it and after completing their own surveys. By the end, they knew more about bats, felt more connected to nature and expressed more positive views of bats. One volunteer said fear and a lack of exposure had shaped their earlier view, a reminder that learning can begin with a simple night outdoors.
Bats make up about 22% of mammal species worldwide, and Australia has more than 80 species. With detectors and local volunteers, researchers can gather information about these often-hidden animals while giving people a closer look at the wildlife around them. More surveys could help clarify which bats thrive in city bushland—and help turn an unfamiliar sound after dark into a reason to pay attention.