According to confirmed data, 12 bat species live in Estonia, with just over half of them remaining in the country for the winter. To monitor their status, a national survey is conducted every year, but it focuses only on large and well-known wintering sites.

Christel Rose Bachmann, a junior researcher in animal ecology at the University of Tartu and the recent recipient of the Young Nature Conservationist Award, explained that the national survey covers major locations such as the Piusa caves or former military tunnels near Tallinn. This, however, leaves a significant gap in the data. "What the survey doesn't reach is the average person's home; because of that, we miss out on a lot of information about which species are wintering where," Bachmann said on the "Terevisioon" morning show.

To fill this gap, a volunteer-based winter bat monitoring initiative was launched, now in its fourth year. The campaign aims to map bat species in places where professional researchers do not typically go and to gather data that will help paint a broader picture of bat distribution and population trends.

No special knowledge is needed to contribute — just checking one's own property, especially the basement, is enough. According to Bachmann, it doesn't have to be an old stone cellar; bats may also hibernate in a basement under a shed or even in an attic.

The key factor is temperature. "For bats to hibernate in a cellar, the temperature is critical. They prefer something close to refrigerator temperature — somewhere around 2 to 5 degrees Celsius. Not too warm and not too cold and there shouldn't be any drafts either," Bachmann explained.

If there's a spot in the home with such conditions, it's worth taking a look. According to the researcher, bats can hide in surprising places, such as small cracks in stone, pipes or even under a glass jar.

Living with jam jars

In addition to mapping species, Christel Rose Bachmann says what matters most to her personally is ensuring that bats fare well when they choose to hibernate near people. That primarily means dispelling myths and raising awareness about how to coexist with the animals.

For instance, it's a common misconception that a bat sleeping in a cellar is cold. The researcher shared an example of a well-meaning person who placed a space heater in their basement, which can actually be harmful. "Bats generally aren't cold. If they don't like the conditions, they'll leave. Coexisting like this is completely possible — they're not bothered. If you go in, turn on the light for a moment, grab your potatoes or jars of jam, whatever you need, the bat is just fine," the junior researcher reassured homeowners.

People don't need to identify or distinguish species themselves. Mobile apps can help with that or they can simply record a sighting as "a bat." All observations are welcome on the Loodusveeb website. Every registered sighting helps scientists build a clearer picture of Estonia's bat populations and protect them in areas beyond the reach of national monitoring.

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