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The Irish Agricultural Museum and Johnstown Castle Gardens will be closed today Sun 18 March due to severe weather warning. We hope to reopen tomorrow as normal.

The museum and castle gardens will be closed tomorrow  (Thurs) and Friday. We hope to reopen on Saturday if weather conditions permit.

The Museum Bat Colony

bats2 low res

Bats hanging in roof of museum.


The museum building provides a nursery roost for one of the largest colonies of soprano pipistrelle bats in the country. The female bats come into the museum in the Spring to roost and to produce and rear their young. Bats are unusual in that breeding pairs mate in the autumn but the young are not born until the summer. This is known as ‘delayed implantation’. The babies or ‘pups’ are born naked and blind but their fur soon appears and covers their bodies and their eyes are open within a few days. They depend on their mother for the first six weeks.

For the past few years, we have carried out regular bat counts throughout the spring / summer season. Counting bats involves standing outside the roost for an hour after dusk and recording the numbers of individuals exiting the building in ten minute intervals. The bats return to our building following hibernation in early spring.

2018 results:-

17 April:  71

19 April:  160

2017 results:-

20 February: First of the soprano pipistrelles emerge.

6 April:  70

13 April:  218

20 April:  408

27 April: 149 (cold evenings may explain this drop on previous week)

4 May: 594

11 May: 650

18 May: 734 (a record count!)

25 May:  716

30 May:  705

21 June:  376 (some bats are now nursing their young and stay in roost)

6 July:  499

13 July:  382

27 July:  241

10 August:  124

18 August:  132


2016 results as follows:-

14 April:  116

21 April:  321

5 May: 714

12 May: 433

26 May: 647

2 June: 605

9 June: 575

16 June: 507

28 July: 383 (colony is now dispersing)

8 Aug: 291

18 Aug: 266

23 Aug: 203

8 Sept: 121

15 Sept:  93

22 Sept:  23

6 Oct:  10

10 Oct:  3

For more info on bats in Ireland go to:-

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