AS the barn owl swooped across the snowy Yorkshire plateau that had taken on the appearance of a frozen Arctic tundra, it was obvious that it was desperate and starvation was taking its toll. It yearned for some shelter from the freezing temperatures.

Meanwhile, the long-eared bat longed to creep under the eaves of an old house, to find the refuge it needed to rest, and the swallow, back from its winter migration, searched in vain for a safe spot in which to nest and rear its young.

Natural habitats for much of our indigenous wildlife is becoming scarcer and scarcer as more green sites are developed. However, this could be rectified if people were aware of how best to encourage such creatures to roost in their outbuildings, however large or small.

And, thanks to the efforts of rangers and volunteers for the North York Moors National Park, a prime example of how to put this into practice exists at the long derelict Low Horcum Farm, right in the basin of the Hole of Horcum, and the nearby Nab Farm.

Climbing down the steep sides of the Hole of Horcum, Low Horcum Farm is approached across the undulating plains of this glacial phenomenon, and as you walk through this spectacular landscape, it’s clear to see why these projects are so important to the wildlife in the local area, which live, hunt and breed here.

Built in 1811, Low Horcum Farm was last inhabited by humans in 1966 and fell into a state of near ruin. It underwent some renovation in 1986. However, over the next 20 years or so, weather and lack of further work meant that the building was in danger of falling down.

In 2008, ranger David Smith came up with an idea of saving this historic building and working with its structure to potentially attract wildlife, in particular, bats, swallows and barn owls.

This was to be an example of how to operate best practice with one of the park’s own buildings – they own the Levisham estate, unlike a lot of the National Park which is owned by others but overseen by them – so this is an example of what other landowners can do to preserve some of their buildings and attract wildlife.

“A volunteer did an initial survey on the farm and found bat droppings and looked up to see four or five long-eared bats clinging to a beam,” said David.

“It needed a lot of work, including making it waterproof to stop it falling into further disrepair, and the original window shutters and door often got kicked in.”

The national park sought specialist advice and a report on the best practice of renovating the house.

David had drawn up some draft specifications, which had to be altered slightly as a result of the report, to incorporate special features to attract wildlife to both Low Horcum and Nab farms.

Work on Low Horcum Farm got underway in March and April 2010, which involved fitting specially-designed windows and ventilation to not only give the building the best chance of survival, but also to offer the best opportunity for wildlife.

“Part of the reason we have the openings on the windows is so that people can see it’s not worth breaking into and also as a structural decision so that the building can ‘breathe’,” explained David.

“The original spec would have meant the same windows being fitted at the top of the building, but then there would have been too much light for bats, so solid shutters were designed with holes so that birds and bats could use them as access points.

“The letterbox hole in the windows, meanwhile, is so that birds can access the building easily without damaging their wings.”

A number of clay pipes that have been fitted into the stone walls to offer ventilation for the building, though not too many as bats don’t like draughts.

However, four openings have been created in the roof and there are specially-designed bat tiles, so bats can access the building this way, too. The roofing felt is also bat-friendly, with a bitumen-type placed over the middle ridge so bats can cling to it without their claws getting stuck, as fibrous felts can be dangerous to this protected mammal, and the wood has been treated with special chemicals, as certain wood treatments can also be damaging to bats.

All of this effort and thought seems to have paid off.

Inside the building, we found plenty of evidence of the presence of bats with lots of droppings and insect wings (their food source), and numerous of swallows nests, long since vacated in favour of their long southbound winter migration.

“From day one, swallows used the clay pipes and I have never seen so many which is great as they tend to always come back to the same area to breed, so it’s great that the farm is doing its job,” said David.

There wasn’t any evidence of barn owls, but David is hopeful that they will use both Low Horcum and Nab farms, especially as they have put together owl boxes below specially constructed owl landing platforms, which have been cut into the walls of both farms.

“It’s been a bad year for barn owls with the snow, but hopefully, in a year or two, when their numbers improve, we might see them come back here,” he said.

Work is still continuing at Nab Farm, and David is planning for lots of volunteers to get involved with monitoring the buildings and their wildlife.

“It would be good to monitor in the summer and see the bats and swallows coming in and out of the building and, hopefully, at some point, owls,” enthused David.

“It just shows what people can do with their own buildings, and if they are doing renovations it might give them some ideas of what they can do to attract wildlife.”

Prick up your ears for some bat facts

Bats are a protected species under two major pieces of wildlife legislation: The Wildlife & Countryside Act 1981 and The Conservation (Natural Habitats &c) Regulations 1994.

Here’s what you should do if you suspect their presence in your buildings:

First and foremost, if you think bats are present in any buildings, especially if you want to undertake any work, seek specialist advice straightway

Check for bats before starting any building work. Place sheets on the ground to collect droppings, which would indicate their presence. Other signs to look for include dead bats, insect remains, smell, urine spotting or staining, grease marks or staining and a ‘chittering’ sound

Bats seek roosts which are clean, warm and stable like roofs, roof voids, roof eaves, gables and chimney/roof joints, wall cavities, tunnels, cellars and mortar gaps in stone or brickwork or around doors and windows which provide small crevices.

If bats are in evidence, obtain a report from a specialist about how best to carry out any work

Carry out building work in autumn or early spring

Ensure that their microclimate is not significantly altered

Never pick up a bat – you need a special licence to handle these protected creatures. If anyone is bitten by a bat they should seek medical advice immediately