title

Winter bat flight activity in urban landscapes of Ukraine

author(s)

Volodymyr Tyshchenko (orcid: 0000-0003-3172-5285) [1]
Igor Davydenko (orcid: 0000-0003-2666-4203) [1]
Oksana Tyshchenko (orcid: 0000-0002-5709-1252) [2]

affiliation

[1] I. I. Schmalhausen Institute of Zoology, NAS of Ukraine (Kyiv, Ukraine)
[2] Taras Shevchenko National University of Kyiv (Kyiv, Ukraine)

bibliography

Theriologia Ukrainica. 2026. Vol. 31: 166–174.

DOI

language

English, with Ukrainian summary, titles of tables, captures to figs

abstract

This paper presents the results of a study of winter flight activity of bats conducted during the winter periods of 2022 and 2024–2026. The aim of the study was to assess the extent of bat activity outside roosts during winter and to evaluate variation in activity in relation to meteorological conditions and local habitat characteristics. The study covered 25 sites in urban landscapes across different regions of Ukraine, with bat flight activity recorded at 15 of them. The surveyed sites included areas of high-rise urban development, low-rise private residential development, urban parks with water bodies, and artificial or anthropogenically transformed water bodies. The results are based on acoustic activity data collected during stationary point counts and combined route-and-point surveys. Bat calls were recorded using ultrasonic detectors and recorders. Only flight call sequences recorded outside roosts were included in the analysis. In total, 292.9 GB of audio files were obtained and analysed, yielding 3785 bat passes. Winter flight activity was detected for six species or species groups: Nyctalus noctula, Eptesicus serotinus, Pipistrellus kuhlii, P. nathusii, P. pygmaeus, and Plecotus auritus/austriacus. The maximum recorded activity levels reached 109 bat passes per hour and 262 bat passes per night. We evaluated variation in winter bat flight activity in relation to meteorological conditions and local site characteristics. Higher flight activity was observed near unfrozen water bodies and major hibernation sites, indicating the importance of such localities for maintaining winter activity in urban environments. The results confirm that winter bat flights in Ukraine are not an isolated phenomenon and may be important for clarifying the seasonal status of particular species. It is suggested that the increasing frequency of winter activity in some bat groups may be associated with warmer winters, urbanisation, and the availability of local microclimatic refugia. The study provides important data for population monitoring and the development of conservation strategies, as it helps identify key winter habitats and supports the planning of measures for their protection.

keywords

bats, winter flight activity, acoustic monitoring, urban landscapes, Ukraine

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