Te Wahipounamu Tarks in the Park Eglinton Ecology Glossary Bat Transects A transect is a line along which samples are recorded. In the case of bats, a transect consists of a line 1km long. The purpose of carrying out bat transects is to count the number of bats in an area. From year to year this gives an idea of whether the bat population is increasing, decreasing or about the same in size.
Bats are nocturnal so transect sampling occurs at night.
The sample typically starts at sunset and lasts 2-3hours. This is when the bats are leaving their roosts in search of food. If transect sampling has been carried out in the area before, the transect is placed in the same place. Each transect is a 1km long. It takes 20 minutes to walk each one.