4 minute read
Bats In Ireland
Header image: A Brown Long-eared Bat (Source: Bat Conservation Ireland)
By Mike O'Connor, Ecologist at IRD Duhallow
Bat Biology and Annual Life Cycle Bats, like us, are mammals – they are warm-blooded and furry, and mothers feed their babies with milk. Long lived, Irish bats typically live for 7-8 years but can live for over 15 years. Their annual cycle follows the life cycle of insects which, in Ireland, are their only food source. They become active in late Spring and hunt by night for their prey using echolocation. In early Summer, colonies of females will roost together in a maternity roost. These are also known as nursery roosts as this is where females will care for their babies/ pups. It only takes six to seven weeks for a bat pup to become independent!
Females leave the maternity roost in August. During this time, bats are busy hunting for insects to build up reserves for the winter. Mating takes place from August onwards, often at a swarming site such as an underground cave. Although, the female is inseminated then, she does not become pregnant until after the winter, when bats are in ‘torpor’. Torpor is different to hibernation as animals in torpor do not go into a state of dormancy; they instead reduce their temperature, metabolism and water balance. When they re-emerge the annual cycle recommences.
Irish Bat Species and Protection In Ireland we have nine resident bat species:
• Common Pipistrelle
• Soprano Pipistrelle
• Nasthusius Pipstrelle
• Daubenton’s Bat
• Natterer’s Bat
• Whiskered Bat
• Brown Long-eared Bat
• Leisler’s Bat
• Lesser Horsehoe Bat
Although they are all insectivores, different species will exploit different niches to hunt. Many bat species will be found around water, however Daubenton’s Bat is particularly associated with water and is known as the Water Bat; they have large feet adapted to trawling the water surface for aquatic insects. The Brown Long- Eared Bat is a woodland specialist and had long ears that allow it to listen carefully for prey amongst the trees. All bat species in Ireland are protected by the Bern Convention, EUROBATS, and by the Habitats Directive (under which all bat species have Annex IV status and the Lesser Horseshoe Bat – generally not found in Duhallow – has Annex II status, affording it extra protection). Bats are very sensitive to development and disturbance can have a significant impact on local populations. For example, if a maternity roost is disturbed or damaged this will likely result in a large number of females failing to rear a pup that year and as bats only rear a single pup per year, it will take a long time for the local population to recover.
Helping Bats Old buildings are often ideal roosts for bats. You may also have bats in your attic! If you plan on renovating old buildings or filling in gaps in your attic, do so in the winter when bats are in their cool winter roosts (e.g. caves, trees). You can then provide alternatives by installing bat boxes nearby. One of the best ways you can help bats (or any animal!) is to ensure they have enough food. Planting trees, letting hedgerows grow and allowing your lawn to blossom will attract insects which will in turn feed bats. Eliminating the use of pesticides such as Roundup will also mean that there will be more insects for bats and will reduce the impact of pesticide build-up through the food chain.
