Baby bats (pups) are usually born in June. They're tiny - about the size of a 50p piece, but when you compare the size of the pup to the mother you understand why the poor mothers only usually have just one baby each year. It's like a human mother giving birth to a full grown five year old child! On rare occasions they do give birth to twins!
June is also the time of year when the majority of grounded bats are found - many of them baby bats. Frequently the bats are just exhausted and simply need time to recover. Often, in the case of baby bats, they've just fallen out of the roost, or been accidentally dropped by their mothers. The babies hang onto the mothers chest while she is flying, and they sometimes lose their grip.
If you discover a bat on the ground, contact the Bat Helpline immediately on 0845 1300 228. The helpline provides free advice, and can even arrange a visit for householders from a volunteer bat worker.
If you find a bat which is in immediate danger, and you need to move it, you should always wear gloves (or use a towel or clothing) to avoid being bitten or scratched. A tiny number of bats have been found to carry rabies.
Note: Handling bats in the UK requires a licence, and appropriate vaccinations. It's also recommended that gloves be worn to prevent bites/scratches. It's illegal to injure, kill, sell or exchange bats (dead or alive) in the UK. It's also illegal to damage or disrupt their roost sites. For free advice please contact the Bat Conservation Trust for advice on 0845 1300 228.