I've found a grounded bat
If a bat is found on the ground or stays for sometime in an exposed position (such as on a wall) it probably means one of two things:
Sick or injured bats
Like all animals, bats can become sick or injured. The commonest reason for finding a bat grounded is because it has been caught by a cat, but it may also have been hit by a car, be ill or simply have become cold, damp or weak due to bad weather.
Although generally small and gentle creatures bats are wild animals and may be frightened or in pain. You must take care not to be bitten so wear protective gloves and handle the bat as little as possible. Most of the UK's bats have such small teeth that a bite will not break the skin. However, a strain of the rabies virus has been found in a small number of British bats, so although the risk is very small, you must take precautions to avoid being bitten or scratched.
The first thing to do is to ensure that the animal is safe. If possible, carefully place it in a secure, ventilated container. Bats are great escape artists that can get through tiny gaps, so do have a well fitting lid.
Bats normally hang by their feet, so ensure that there is a non-slippery surface to which they can cling. This can often be provided by lining the container with kitchen towel and trapping the edge of the towel under the lid, so that it hangs down the inside of the box.
The most important thing you can provide for the bat is water, but bats can make a mess if a container of water is provided and may then become cold and wet. It's best to get a small lid from a jar, soak a piece of kitchen towel with water and place this in the lid, so that the bat can suck moisture from the paper if it wants too.
With the bat secure and watered, place the box in a dark and warm place, before calling the bat helpline. Because bats are rather tricky to care for successfully, a volunteer will usually arrange to visit you. They will assess the bat's condition and if it is not fit to be released, take the bat away to be cared for. If the bat recovers, it will be brought back to be released, as bats know their home area.
All British bats are small, so it is sometimes difficult to tell if you have an adult or baby bat.
Baby bats will mostly have no fur or just a thin, greyish 'fuzz'. As the majority of bats are born during a short period in summer and grow up quite quickly, you are most likely to encounter true baby bats in June or July.
Like all mammals, baby bats suckle their mother's milk and need to be close to mum to keep warm and healthy. The greatest chance of successfully keeping a baby alive is to get it back to the roost. Failing that, it requires the assistance of an expert carer.
Babies cannot fly for the first few weeks so it is likely (but not always the case) that the roost will be very close by. As they get older, like children baby bats become more inquisitive. While the mother is out at night feeding herself her baby may wander off and find its way through a tiny hole and not be able to find the way back. Sometimes, if the weather is particularly cold, hot or wet bats may abandon a roost. Then some babies may get left behind.