Urban environments have the potential to support a healthy bat community if suitable resources are readily available for a diversity of species. For example, bats can use water sources in urban areas, such as drainage ditches and ponds. However, when these sources are not available or have limited distribution, bats may utilize an alternative source; residential swimming pools. Thus, if such pools could be made more accessible, this may improve urban habitats for bats. Over three years, we conducted behavioral observation and acoustic surveys at 20 pools in suburban Fort Worth, Texas to determine whether pool treatment, shape, lighting, and size influenced bat activity. Using night vision, thermal cameras, and acoustic detectors, we recorded bat activity over the pools. Our results revealed that residential swimming pools can provide at least two resources for bats; drinking and foraging. Yet access and potential availability are dependent on the pool characteristics and the importance of characteristics depended on the type of activity being exhibited. For example, while pool shape affected drinking behavior with more bats drinking at straight-edged pools as opposed to curved-edged pools, it had no impact on foraging. Water treatment types also influenced activity: mineral- and salt-treated pools supported higher drinking and foraging activity compared to chlorine-treated pools. Artificial lighting at pools deterred both bat presence and resource use and lastly, pool size emerged as a key factor for species diversity, with larger pools (>70 m2 in size) supporting more species and activities. These findings emphasize the potential of urban swimming pools as resources for bats and provide practical guidance for designing bat-friendly water sources in residential areas.

The availability and accessibility of water resources are important factors influencing bat presence in urban areas. Bats access water sources on the wing and may not be able to access water sources with smaller surface areas or those obstructed by clutter. To address this, we conducted a study to assess the extent to which variation in available water surface area influenced the abundance of bat activity and the diversity of species present in an urban area. We surveyed six study sites in Tarrant County, Texas in 2023 and 2024 using a thermal camera to record the total duration bats were present and the number of observed drinking events and an acoustic detector to record the number of bat calls, number of drinking buzzes, and number of species during each survey. We also used a drone to assess water surface area metrics including the fundamental and realized surface areas, maximum patch sizes, and longest stretches of continuous area. Comparing each of these independent variables with each dependent variable, we determined that decreasing length of available surface area resulted in a corresponding decrease in bat activity and diversity. In particular, we observed a reduction in drinking activity, the primary indicator of water resource use. In other words, we found that as water sources dried up and increased in clutter the length of the available surface area prevented or deterred bats from accessing as a drinking resource. Therefore, effective management of water sources in urban areas must include the removal of any clutter to improve the accessibility of water sources for bats and encourage a diversity of urban wildlife.