Any bat ready for release should have satisfied the criteria set out in the Rehab section. All bats should be test flown and where necessary given extra flight practice prior to release.
Release location
- It is extremely important that a bat is released where it was originally found, or as close to this location as possible, unless there is a problem with the site.
- Bats are loyal to their roosts and thus it is important, where possible, to release them back into a familiar area.
- Consider the environment that the bat is being released into
- Are there roosting opportunities available? In cases of long-term bats being released, the environment may have changed significantly and this should be investigated prior to release.
- If the bat is from a known roost, the site should be checked to confirm that the colony is still using the area this is more important for juveniles.
- Do extra provisions for roosting need to be made?
- Where a bat’s roost has been lost and the bat has been in care for a long period of time, the individual may benefit from being released from a ‘familiar’ artificial roost, for example a bat box that it has roosted in and can access easily, in or close to the place of finding.
- Is there any chance that the released bat will carry infection into the local population? (This is less likely if isolation and good hygiene have been used).
- Not enough is known about territorial behaviour and population densities of many species of bats. Bats are colonial creatures and releasing them within the location of their own colony will minimise problems. If a bat is released into a new site, (because the original site is unknown or very unsuitable) consideration should be made of the type of eco-system/habitat the species normally inhabits. Additionally the bat should have no appearance of infectious disease that it might introduce to the wild population.
How to release – timing
- Bats are nocturnal creatures and emerge from their roosting sites at dusk. The bat should be released at dusk time so that it can orientate itself properly and avoid daytime predators that it would not normally come into contact with.
How to release – weather conditions
- Where possible very cold, windy or rainy evenings should be avoided as these conditions are less favourable to bats generally and a successful release is less likely in these conditions.
How to release – height
- In their natural environment bats will normally take off from a height, dropping and swooping before flying off towards their foraging grounds.
- This can be from a high structure like a wall or window ledge, or a gloved hand.
- The bat will warm itself up and survey the surroundings before flying off. The release may take up to 45 minutes, patience is required!
- It is important to make sure the bat flies up and away on release and has not fallen to the ground nearby.
Post-release monitoring
- Where possible, monitoring should occur following release. This can be extremely important as the roost site is not always known and bat colonies frequently re-locate.
- This is also an opportunity to involve the original finder of the bat, where interested.