How to build a wildlife tower

Wildlife Tower Complete

What’s a wildlife tower?

A wildlife tower is a very small building that provides nesting and hibernation opportunities for a huge range of wildlife. The first ones we designed have been occupied by at least four species of bat including Lesser Horseshoe, over-wintering butterflies and other invertebrates, Little Owl, Kestrel and Barn Owl nesting simultaneously as well as House Sparrow and other small birds. House Sparrow is Red Listed as a Species of Conservation Concern, Kestrel and Barn Owl are Amber Listed.

This proven design has a footprint of only 2 metres x 2 metres, is 4.5 metres tall and costs around £10,000. Low-cost alternatives have been built from reclaimed house bricks, concrete blocks, and in one case all-timber. However, the original concept is of a building that’s not only beautiful and perfect for wildlife but will last for at least 100 years.

Wildlife Tower Complete Snow   Wildlife Tower Foden   Wildlife Tower Bill Bailey

Are architects’ plans available?

We can supply professional architectural drawings for your planning application in return for a nominal £50 donation. This represents a huge saving on the cost of having your own plans drawn up. Please make your donation here then email your request to info@nullbarnowltrust.org.uk.

Why build a wildlife tower?

Although rather expensive compared with a simple nestbox, this purpose-made building is the ideal solution where a traditional Barn Owl site is being lost and a long-lasting alternative is required. Where a proposed housing estate includes the loss of an old building or veteran hollow tree, the required wildlife provision can be made in the form of a Wildlife Tower rather than placing it inside a residence or garage block. A Wildlife Tower can also be created as a long-lasting memorial to a loved one.

Wildlife Tower Building Foundations  Wildlife Tower Building Low Walls  Wildlife Tower Building Outer Wall  Wildlife Tower Building Roof

What species are provided for?

Our wildlife building includes lots of spaces thoughtfully designed to offer habitat for as many different wild creatures as possible. Species catered for include Barn Owl, Kestrel, Little Owl, Stock Dove, small hole-nesting birds such as Blue Tit and House Sparrow, plus Robin, Swallow and House Martin, invertebrates such as over-wintering butterflies (e.g. Peacock, Red Admiral) lacewings, bats (e.g. Horseshoe, Pipistrelle, Serotine, Long-eared, Daubentons), toads, slow worms and lizards.

Construction

In order to be long lasting, the building should have a concrete foundation (with bare earth in the centre) and stone walls. Concrete blocks, reclaimed bricks and natural stone may be used; however natural stone is preferred as it usually blends in better and affords more opportunities for wildlife to colonise the walls. The more cavities that can be incorporated, and the rougher the walls, the better.

Want to see more detail? See the photos of a wildlife tower being constructed.

Wildlife friendly features

East Facing Wall: the Barn Owl entrance hole is 3.5 metres above ground level and leads into a generous deep nestbox. To maximise chances of occupation the hole overlooks open ground and is therefore highly visible to any passing owl. In addition, areas of rough tussocky grassland are provided for owls to hunt over.

West Facing Wall: Kestrels prefer a shallow open-fronted nest cavity. Directly below the Kestrel nest is a small hole leading to a small, deep nestbox for Little Owls to use.

A perch is provided just below and in front of each owl hole. This, plus the generous roof overhang, makes the site safer for emerging fledgling owls.

South Facing Wall: on the warmer south-facing wall there are numerous other cavities in the mortar to suit a range of invertebrates (spiders, wasps, etc).

All Four Walls: on all four sides, the building has a variety of sparrow-sized openings for hole nesting bird species. Stone piles were left at the foot of the refuge to provide a habitat for amphibians and reptiles.

Bats: the lower half of the building is a hibernation area for bats, designed to be permanently dark, cool and damp with a simple earth floor. A variety of bat species can access this through a wide horizontal slot situated just below the level of an internal floor, which separates the top half of the building from the hibernation area.

A second bat hibernation space is accessed through a smaller horizontal slot at the top of the north-facing wall. Breeding bats need a much warmer cavity so the third area for bats (the bat nursery) is situated behind the top of the south-facing wall. This extends right up to the roof tiles and has its entrance hole at the bottom thus trapping warm air.

Photos of wildlife friendly features and provisions.

Does it work?

Yes! Our first Wildlife Tower has had Barn Owls and Kestrels nesting simultaneously plus visiting Little Owl and bats. Our second Wildlife Tower has so far had visiting Barn Owl, nesting House Sparrow, and four species of bat including Lesser Horseshoe and Brown Long-eared. Both towers have been colonised by lichens and a variety of invertebrates including lacewings and over-wintering butterflies.

Wildlife Tower Barn Owl Provision   Wildlife Tower Roost Debris   Wildlife Tower Nest Debris

History and acknowledgements

As far as we know, the first stone building made specifically for Barn Owls was built in East Devon in 1991. The second, built in Lincolnshire in 1998, was designed by Bob Sheppard and Garry Steele and we are grateful for their helpful comments (thanks guys!). The first to incorporate provision for a really wide variety of species was designed by us and stimulated by the making of Wild Thing I Love You, a programme by RDF Media for Channel 4 Television in 2006 presented by Bill Bailey. Our second Wildlife Tower was built as a memorial to John Woodland, BTO Regional Rep for Devon from 1993 to 2008.

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