Nest-boxes, new homes for choughs

DSC01433By Liz Corry

Last month we gave you an insight into Cornish choughs and what people are doing there to help them. This month we continue our travels and will take you north across the border to Wales. Known for its lush valleys and majestic mountains, Wales is also home to about three-quarter’s of the UK’s choughs.

visit wales website image

The Welsh name for a chough is brân goesgoch meaning ‘red-legged crow’.

Wales is broadly categorised into four regions; north, mid, west, and south. Choughs can be found more or less along the entire Welsh coastline from the Gower Peninsula in the south to the isle of Anglesey in the north.

They can also be found inland from the coast nesting in abandoned quarries or mineshafts. Most famously at the Llechwedd slate caverns , North Wales, where a pair are known to nest much to the delight of the tourists deep underground. A video made by the RSPB gives you more of an insight and can be viewed here.

Over the past two decades researchers working with these choughs have seen more and more inland nests becoming abandoned and breeding pairs disappearing. Ceredigion had five breeding sites in the late 1980s. Ten years later it was down to one. Montgomeryshire has seen a complete loss. It is believed that the boom in natural predator numbers, namely peregrine and goshawk, has not helped matters.

Silurian shale coastline in Wales.

Silurian shale coastline in Mid Wales.

Coastal nest sites are also under threat, but in this case it is due to natural erosion. A lot of the coast is limestone, sandstone, or shale and easily erodes. Looking at the photo on the right you wouldn’t think a bird would chose to build a nest on these cliffs. Yet they do, often with success, although a few years down the line the ledge might give way falling into the sea and a new nest will need to be built.

Nest-site availability is a very strong limiting factor in population expansion. In the late 1980s Scottish researchers had already shown the effectiveness of providing choughs with artificial nest-sites. Wales took on board this advice and started providing nest-boxes or ledge supports at various coastal sites. Within a few years just over two thirds of the artificial sites were being used. As of 2008 choughs at 22  artificial nest-sites successfully raised a total of 335 fledglings!

On a recent holiday to Wales I had the privilege of meeting Tony Cross, a champion chough supporter and the person responsible for designing the artificial nest-boxes (which we use at the Wildlife Park). Tony very kindly spared time to show me around some of the sites and teach me more about the Welsh choughs. Having ringed over 4,000 choughs and followed many individuals for several years there is a lot we can learn from him.


This area was once used by choughs to raise chicks, but has now been abandoned.


An abandoned mine shaft once used by nesting choughs.

The first stop was at an abandoned mining area where a pair of choughs used to nest. It is hard to see from the photos, but they chose a spot down a deep shaft which kept them fairly well protected from nest predators.

The land around looks quite healthy in terms of insect availability with cattle grazing pastures and its away from built up areas.

This is probably one of those sites which ‘suffered at the talons’ of the goshawk (although great news for the goshawk I guess).

As it was outside of the breeding season we didn’t disturb any nesting choughs. Tony is a licensed ringer and licenced to approach nests. I would not have been able to do this without him.

We then drove to the coast to take a look at some of the nest-boxes Tony and his colleagues have fitted to the cliffs. It is quite a challenge as they have to find a site that they can access, but at the same time deter egg collectors and the like from reaching it. In recent years Tony has sadly found activity at boxes suggestive of human raids rather than natural predators (and we thought those days were over). One clue being that ravens don’t need to use ropes!


Nest-boxes are positioned away from potential land predators in areas where choughs are trying to breed naturally but fail.

The boxes are constructed from either marine grade plywood or Ecosheet©, a recycled plastic boarding. The shape is designed to mimic a natural cavity so they are quite narrow and deep.

Tony Cross indicating how far back the nest box reaches.

Tony Cross indicating how far back the nest-box reaches. This one is unusual in that it is positioned on top of the cliff.

The front of the box has and overhang which, apart from acting as a deterrent to something trying to reach in, makes it feel a bit more enclosed and sheltered for the birds.

cropped nest box

An chough nest-box facing the sea (the black dot in the sea is a seal, trust me)

One factor Tony did not consider when first designing these boxes was how badger-proof they would need to be. Don’t be alarmed, Welsh badgers have not adapted to have opposable thumbs and learn rope skills. They do, however, burrow and at one particular sight they have given the nest-box a bit of a battering pushing it out of place.

One nest-box needs re-positioning after a run in with badgers.

The boxes need to be checked each year as they do suffer from being exposed to the sea air. As long as the roof remains dry and there is no risk of collapse the boxes can be used for several years. It normally takes a year before a breeding pair move in to a new box. Lots of HSE forms to fill in, quality control tests, and the long wait for the Royal Court date (Jersey in-joke sorry).

It is clear that the work Tony and his colleagues are doing has made a great difference to the Welsh chough population. Jersey’s choughs may well benefit from the same practices as these birds have no experience of wild nest sites and will need some encouragement.

Choughs in South Stack, Anglesey

Choughs at South Stack, Anglesey

Many thanks once again to Tony for taking time out. You can find out more about his work at