Counting bats

Participate in the BC Annual Bat Count

The BC Annual Bat Count is a citizen science program to annually monitor bat populations in roost sites. Abandoned houses, barns, church steeples – and even currently-occupied structures – can provide a summer home to female bats and their young. Monitoring these “maternity colonies” can give biologists a good idea of how bat populations in an area are doing from year to year. With the occurrence of White-nose Syndrome in North America, monitoring these colonies is more important than ever.

When to count

Ideally, the Bat Count includes four counts during the summer:

  • two between June 1 and 21 (before pups can fly) and
  • two more between July 11 and August 5 (when pups are flying and exiting the roost with their mothers).

Doing all four bat counts allows us to best compare data from year to year and between sites. However, if you don’t have time, you can choose your level of participation:

  • Level 1: Bat Reporter – One count over the summer (try between June 1 – 21)
  • Level 2: Bat Tracker – two counts between June 1 – 21 
  • Level 3: Bat Enthusiast – Two counts between June 1 – 21 and two counts between July 11 – August 5

How to count

Generally, these bat counts are a lot of fun and are pretty simple:

  • Arrive at your bat roost at sunset (bats will begin to emerge at dusk).
  • The air temperature should be at least 12 deg (C) with no rain and low wind speed.
  • Sit or stand outside so that the bats’ exit point is visible from a comfortable distance. More than one person might be needed if bats are exiting from multiple points.
  • Tally the bats as they fly out for their nightly insect-eating. Use a counting app on your phone or a hand “clicker” to make counting easy. Record your observations on the data sheet (see download below).
  • Mail us your data sheet at the end of the summer.
  • Do not enter bat roosts and never handle a live bat.
  • Please respect private property. Ask permission if the bat roost is on someone else’s land.

Resources

To learn more about the counts and how to collect valuable bat data, click below: