# Acoustic monitoring with miniature drones shows reduced Myotis bat occurrence with altitude and drone movement

## TL;DR

Miniature drones can monitor bat activity in the air, showing that certain bat species are more common at lower altitudes and when the drone is stationary.

## Contribution

A new method for using small drones to study bat distribution, revealing how altitude and drone movement affect sampling efficiency.

## Key findings

- Hovering drones detected more bats per minute than moving drones for certain species.
- Myotis bats were more frequently detected at lower altitudes (0–60 m).
- Miniature drones can efficiently monitor bat density in the airspace.

## Abstract

Our understanding of aeroecology is hampered by the challenge of sampling the air column, especially for nocturnal species like bats that forage high in the airspace. Nonetheless, monitoring endangered bat populations is vital for conservation efforts. Drones (unoccupied aerial vehicles) offer a relatively safe, cost-effective, and non-intrusive option for studying aerial wildlife. Here, we present a method for measuring bat distribution in the airspace using miniature drones (Mavic Mini 3 Pro) that are small enough to have negligible impacts on the bats themselves. We investigate how habitat, drone altitude, and drone movement influence bat sampling efficiency. A hovering drone detected more bats per minute than a moving drone for the EPNO complex (Eptesicus fuscus and Lasionycteris noctivagans) and all bats. Thus, we recommend the use of hovering point counts for surveying bats via drone. The Myotis complex (M. septentrionalis, M. lucifugus, and M. leibii) was more frequently present at lower altitudes over the sampled range (0–60 m). We conclude that bat taxa differentially occupy sectors of the air column, and that bat density in the airspace can be efficiently monitored by miniature drones.

The online version contains supplementary material available at 10.1038/s41598-025-96255-5.