In the middle of the grassland that will become Lilbourne Meadows to the north of Prologis RFI DIRFT, sits a small, square, windowless house. Although it looks like a gingerbread house straight out of a fairytale, this mysterious little building is in fact, a specially designed bat house.
Early in the planning process for the latest phase of DIRFT, our ecology consultants carried out a series of ecological surveys. They found that while several common species of bat intermittently forage or commute across the site, the derelict farmhouse at Shenley Farm close to the eastern boundary, was used as a maternity roost by Brown Long-eared bats Plecotus auritus.
Recent surveys have confirmed the continued presence of this maternity roost as well as a further summer day roost of Common Pipistrelle Pipistrellus pipistrellus bats within the nearby New House Farm.
We need to demolish what remains of both Shenley Farm and New House Farm to make way for the new development, so to give the bats roosting continuity, we built a bespoke bat house before any demolition work could begin.
Working with Natural England and the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire, the bat house was designed to best practice guidelines to provide the best possible environment for the bat species identified on site.
The Bat House
Constructed using local brick, the building includes both a roosting loft and a hollow block hibernation wall. The building is secure against predators, but offers plenty of ways for the bats to move freely in and out. There are bat access tiles on the roof, bat access bricks in the east and west walls, while between the fascia and soffits there is a 30mm gap through which bats can fly.
Now that the construction of the bat house is complete, our next task is to encourage the bats into the new building by ‘seeding’ it with droppings from Shenley Farmhouse and New House Farm. Then, as we move ahead with the habitat works across Lilbourne Meadows, we will take further steps to support the bat population. Specifically, we will install a series of bat boxes in trees across the site for roosting, while the new planting and landscape enhancement will provide high quality foraging, particularly around the ponds we are creating for the Great Crested Newts.
Every new chapter in the unfolding story of Lilbourne Meadows proves to be fascinating. But, along with the Sand Martin nesting wall at Ryton Pools, the bat house at DIRFT is definitely one of our more unusual build-to-suits.
By Chris Lewis