By Miranda Collett
Jersey’s Woodland Bat Project was created in September 2014 and Stage One was to erect 58 Kent bat boxes in five Jersey woodlands including Val de la Mare, St Lawrence (Waterworks) Valley, La Hague water filling station, Don Gaudin in St Peter’s Valley and St Catherines Woods. We also put up five Schwegler woodcrete boxes which are of a much tougher design, one per woodland. These boxes were all put up between October 2014 and May 2015. Importantly, with each box we placed a small shelf underneath the box to collect any droppings that any occupying bats may produce.
Kent bat box
The Kent box tends to attract crevice-dwelling bats which include the pipistrelle species that we have in Jersey (see list of Jersey bats here). The object in Jersey was to provide more roosting opportunities for bats and to learn more about our woodland species of which there has been little research so far.
I obtained the relevant licencing from the Department of the Environment (see Jersey details here) and with a team of volunteers from the Jersey Bat Group we checked the boxes for signs of occupation during the last week of each month after April. Up until September there was no evidence of occupation. However………….
On 30th September I received several excited messages from Cassie, who monitors the Waterworks Valley sites, to say that there were bats in the inner crevice of one of our boxes, WW11. This is one of the higher boxes and lies in an area which has proved very rich in bats – we undertook some static echolocation monitoring in our woodlands during August.
I was out of the Island when Cassie made the discovery, but asked if some of the monitors could go down and do some echolocation recordings that night so we could get an idea of which species was in the box. It appears that there were three bats in the inner slot of the box. Echolocation recordings on emergence indicated that the bats were Nathusius’ pipistrelle Pipistrellus nathusii (see also Nathusius’ pipistrelle website) a migrating species which is relatively rare in the UK but has been recorded in Jersey many times since it was first recorded in 1987. There was also one dropping on the shelf which was collected for analysis.
The Nathusius’ pipistrelle is slightly larger than the more common, common pipistrelle (P. pipistrellus) and soprano pipistrelle (P. pygmaeus) and weighs around 6-10 grams. It is of a more uniform colour than the other pipistrelles and is normally distinguished by its lower frequency echolocation, although it can be confused with Kuhl’s pipistrelle (P. kuhlii) which has also been found in Jersey.
Cassie kept me informed and the bats did not go away. On my arrival back to Jersey on 20th October I went down to Waterworks Valley and was delighted to find one bat in box WW11. I also looked at some of the nearby boxes and discovered a bat in the outer crevice of WW13. It looked like another pipistrelle but we will need to do some more monitoring to determine its exact species. As these boxes were put up in January it has taken only 8-9 months for two of them to be occupied. I think this is very encouraging for the rest of the project.
This winter we hope to put up some more Schwegler woodcrete boxes which are far longer-lived and which have had good results in other projects in the UK.
We are grateful to Jersey Water, National Trust for Jersey and the Department of the Environment for permission to use their premises for our project. We also thank the Co-operative Eco Fund for a generous grant toward our project. A big thank you too to the monitors who have inspected the boxes every month. Many thanks to Bedfordshire Bat Group for use of their photograph.
For more details on our projects or information in general on bats in Jersey please go to our website www.jerseybatgroup.org
