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Roost Monitoring

Little brown bats roosting in a furnace room

A roost is a structure that bats use for shelter. In summer, groups of adult females roost together in maternity colonies to give birth and raise their young. Maternity roosts must be warm to promote growth of the young bat pups, which is why buildings and attics are popular roost sites for species such as the little brown bat.

Locating maternity roost sites is an important first step toward monitoring summer bat populations. Once a roost has been located, bats can be counted as they emerge in the evening to go forage.

If you have a roost in your building that has become a nuisance, see Living With Bats.

  • Report a roost: If you know the location of a bat roost that is regularly used by more than one bat, please complete a Site Data Form (Word doc 27 kB).
  • Monitor a roost: Help document maternity colony size and timing of reproduction by volunteering to count bats as they emerge from their roost in the evening. See the Roost Count Protocol (Word doc 36 kB) for instructions and please fill out the Roost Data Sheet (Word doc 68 kB) to report the number of bats you count.
  • Bat house: To report a bat house that you have, please fill out the Bat House Report Form (Word doc 31 kB) . If you are interested in building a bat house, please contact us. Learn more about bat houses at Bat Conservation International.