Nathusius’ pipistrelles are small bats, whose back is reddish-brown and the stomach grey-brownish. Young bats are blackish-brown with a grey stomach. They prefer to live in parks, but can also be seen in park-like natural small woods, alleys, and near buildings. They hunt at night, flying 5–8 metres from the ground between treetops or 4–6 metres above waterbodies. During flight, they often change direction, circle around in one spot, and make sudden jumps. Nathusius’ pipistrelles prefer to feed on butterflies and blood-sucking Diptera. They often live in large colonies that hide in tree hollows or between the walls and under the roofs of wooden houses during daytime. As all of our local bats, Nathusius’ pipistrelles are protected (protection category II). Even though there are no predators in the wild that endanger them, they are still very sensitive to human activity. More than 65 species of mammals have been registered in Estonia, 14 of which are bats or Chiroptera. There are about 500,000 bats in Estonia. In Tallinn, their most important feeding places are Kadriorg Park, Pirita River Valley, Raku lakes, the area surrounding Ülemiste Lake, Astangu, and Rocca al Mare.