Bats and Halloween

Bats are usually the first flying animal that comes to mind when we think of Halloween, but have you ever wondered why these mammals are associated with such a creepy holiday?

One theory is that it all started with Scottish and Irish migrants moving to America in the mid-1800s who brought the Celtic holiday of Samhain (later to become Halloween) to the continent.

It is during this spooky season that bats from the North-eastern United States begin to swarm in preparation for hibernation or for the journey south for a warmer winter. It’s possible that the Celtic arrivals noticed this spooky spectacle and began to associate it with the annual autumn holiday.

And who could forget the sanguine tale of Dracula and its association with the vampire bat. Every Halloween people get out their fake fangs and capes to dress up as the famous count, but do vampire bats really deserve the bad reputation? In reality there are only 3 species of vampire bat, all native to Central and South America. They weigh a minuscule 25-40 grams on average and mainly feed on livestock and birds. All in all they are relatively harmless to us humans. BatAs Halloween fast approaches in the UK, what are our native bats up to?

After having their young in May to June, our native bats spend August and September fattening up in preparation for the autumn and winter months. October brings cooler, wetter weather and a reduction in insect prey. Bats become much less active before going into hibernation over the winter until March/ April.

Bat handlingWhat does this mean for the bat survey season and planning applications?

Due to the consistently low temperatures and lack of foraging opportunities in winter, it is unlikely that bats will emerge from their winter roosts, so bat flight surveys will need to be put on hold until the weather warms up again in May.

Bats are a material consideration during the planning application process and investigating their presence early on can prevent delays further ahead in the development schedule.

The autumn and winter months are a great time to conduct the preliminary roost inspections of trees and buildings that are needed to determine if bat emergence or activity surveys in the summer season will be required.

Getting this assessment done now will either determine that your development does not require further surveys or it will clear the way ready for the required surveys to begin as soon as the bat survey season starts in May.

We have a number of licensed bat ecologists who are able to undertake tree and building assessments throughout the year, activity surveys from March to October, emergence surveys from May to August/ September and hibernation surveys from December to February.

Our ecologists have extensive experience in surveying and designing mitigation for protected species and habitats. We can advise you on survey methodologies, legal protection, mitigation options and the timing of development works. Click here for examples of our work.

For more information about the Ecology Services, we can offer, call us on 029 2065 0331 or contact us on