By Harriet Clark

December was another quiet month for the choughs, and it seems, for now at least, their exploratory days are over. The birds rarely ventured further than half a kilometre from the aviary, apparently content probing for insects in the grazed fields near the aviary. The ten juveniles were at least a little more adventurous than the older six birds however, and for the first few weeks in December, could faithfully be found every morning, perched on the muddy cliffs at the mouth of Mourier Valley, digging furiously, doing what looked like some impressive excavation work!

Chickay, Bean and co digging on their “favourite” cliff. Photo by Harriet Clark

Quite what the birds were finding there is unclear, but our pitfall trapping showed that there were still plenty of insects about, including rove beetles, ground beetles, minotaur beetles, earthworms and leatherjackets. Leatherjackets (crane fly larvae) are known to be a favourite food item for choughs, and this is certainly evident with our birds as they excitedly, and rather comically, chase each other when one chances upon the prized invertebrate prey.

Unsurprisingly December brought more downpours, fog, gale force winds and hail, but I am thrilled to say that the choughs have battled through, all in good health. We only had one morning of heavy frost, and interestingly, early that day the birds were nowhere to be seen in the usual grazed fields.

Handfuls of leatherjackets to be found! Photo by Harriet Clark

We eventually tracked the flock to Mourier Valley, and found them foraging amongst the dead stands of bracken. We hadn’t observed the birds foraging there before, but closer inspection revealed the soil was very soft, and presumably easier to probe for insects in than the harder ground of the grazed fields. Will, Jennifer and I also adapted to the windier, wetter weather and located several “good” gorse bushes to huddle beneath or, in Jennifer’s case, lie flat on her back underneath, just to have a bit of a break from the pounding, relentless wind!

The choughs weighing themselves in the aviary. Photo by Harriet Clark

December marked seven months of living free for the older birds, and three months for the juveniles. Faecal samples were submitted to the laboratory at Durrell as part of our continuous post-release health screening. The results were very encouraging and showed that the birds’ parasite load has decreased since their last screening in October. We also monitor their health by weighing them, and we now have a second set of scales so that when the weather allows we can weigh as many individuals as possible. Despite halving the quantity of dry mix and insects that we feed the choughs in October, regular weighing shows that the birds definitely aren’t suffering from lack of food, with several even putting on weight. This and their low levels of parasites, indicates the birds are clearly maintaining good body condition and are acclimatising well to their environment.

Sorel is ideal habitat for minotaur beetles, which prefer short grazed turf and plenty of sheep dung for the larvae to feed on. Photo by Harriet Clark

The older choughs developed a new habit this month; during feeds they would collect several mealworms or a “beakful” of dry mix and fly out of the aviary, disappearing out of sight to a nearby field. At first we wondered whether they were simply taking their food away from the group to eat it in peace, but careful observation revealed that although sometimes they were eating it, other times they were digging a hole and hiding the food in there. Choughs caching mealworms has previously been observed by Eric Bignal in his study of supplementary feeding wild choughs in Islay (report published in British Wildlife), and the birds there were seen marking their caches with different objects such as feathers, to aid finding them later. Although we feed our choughs twice a day, they don’t receive a huge amount and it is quickly consumed, so perhaps the adults are caching food so that they have access to it later in the day.

Evidence of choughs at work. Photo by Will Campbell.

At the beginning of the month we started to notice several muddy patches scattered randomly across the sheep grazed fields. We quickly discovered the culprits- the choughs of course. They seem to have developed a penchant for tearing up the grass, and we’ve observed the group many times this month energetically flinging clumps of grass into the air, no doubt searching for soil invertebrates to feed on.

Icho and three of the adults tearing up the grass in search of insects. Photo by Harriet Clark

The adult female Mauve, finally gave up pursuing her previous partner Green this month, focussing her attention instead on the two-year-old male White. We monitor the location and activity of the birds hourly throughout the day, and White and Mauve are almost always found foraging close together, often separate from the rest of the group. During supplementary feeds the pair also feed from the same dish, and regular roost checks throughout the month revealed that rather than returning to the aviary with the rest of the group at sunset, they roost together in the quarry. Fingers crossed we may now have two potential breeding pairs to keep an eye on in 2015!

Regular visitors to Sorel will undoubtedly have noticed significantly fewer sheep out and about on the north coast towards the end of the month. Unfortunately several young sheep were taken ill and because it was not clear at first what the problem was, the flock was moved into the fenced-off aviary field for close monitoring and care by their shepherd Aaron Le Couteur (CS Conservation). Test results revealed the sheep had a gastro-intestinal problem, and, being a primitive breed, they have physiological differences so often respond differently to parasites compared to commercial sheep breeds. The flock has now been treated with a novel drug and are fortunately well on the road to recovery.

We sadly said goodbye to Will at the end of December, after four months on the project. He started volunteering one week after the juveniles were released and has been following their progress ever since, spending many hours radio tracking the birds across the island and observing their antics on the cliff tops at Sorel. Will has been a huge help both in the field and in developing our invertebrate monitoring project. We wish him every success as he moves to England to pursue a career in wildlife conservation. You can read his brilliant piece about his time on the project here

By Will Campbell

In October Adam wrote about his time with the choughs on the sunny north coast of Jersey. However, it’s not all sunshine and calm days on our coastline and here Will recounts his time following the choughs into a Jersey winter.

My toes are numb as I squeeze my way past gorse bushes and through muddy fields, arm and radio antenna outstretched, feverishly waiting for the reassuring ‘pip’ from the SIKA that indicates a nearby chough. Because, once you have found one chough (the ‘Judas chough’ as fellow volunteer Jenny calls them), you can be pretty sure that the others are nearby.

I trudge, stooping into the wind, to a high point and wave the antenna in every direction for what seems like the hundredth time. At last a faint ‘pip’ comes through the SIKA slung over my shoulder. I look anxiously ahead into the wind and rain but instead of the familiar acrobatics of a chough I see nothing but a thick sea mist. Dejectedly I trudge on, in the vague direction of the ‘pip’ in order to pinpoint their location.

It’s at times like these when some people might ask, ‘Why?’ And I tell them that although data collection isn’t easy, no matter how minute and irrelevant it may seem, it is absolutely necessary to build the bigger picture. A big part of my time with the choughs was spent radio tracking them – essentially finding out where they were and how far they were from their mates. Doing this up to eight times every day allows you to amass a huge amount of data, which can in turn help answer loads of questions in matters such as social sub-groups, home range, and even potential breeding pairs and nest sites come the spring.

Although I’ve painted a pretty grim picture at the start of this piece, I did in fact experience all four seasons in my four months up on the north coast, sometimes, it seemed, in the space of one day. At 8am I might be huddled with the sheep in what little shelter there was from the wind and rain, and by 11am I could be sunbathing in a field, cursing myself for forgetting my sun cream.

The most extreme weather I faced up at Sorel was during gale force 8/9 winds where simply walking from A to B was a challenge. Even the choughs were wisely sheltering in the aviary from the onslaught. Harriet and I noticed an upturned kayak in the sea and, fearing the worst, she called the Coastguard. It didn’t take long for a search plane to arrive and start scouring the sea. Luckily, it turned out the kayak had never been occupied and the plane turned back to what must have been a very bumpy landing.

It was during the warmer half of my placement that the choughs decided to clock some air miles and check out what the rest of the Island had to offer. This left us frantically driving around the west of Island, but ‘as the chough flies’ is a much quicker way of getting around than ‘as the Skoda drives’. It was only due to the very welcome tip-offs from local bird-watchers that we were able to find the choughs down at Beauport probing amongst the cliffs; apparently oblivious to the panic and excitement they caused us. It was incredibly rewarding to see the previously captive birds exploring the island and always making it back to the aviary with impeccable timing to demand their lunch.

The choughs seem to have an uncanny ‘spider sense’ when it comes to feeding time. The idea is that, once you have put out the dishes, you give a tinnitus-inducing blow of a whistle and the choughs appear in unison to merrily scoff all the food. The birds have been trained to the whistle to try and give us an element of control, for example if they need to be shut in the aviary. In practice, however, the choughs are canny little birds and seem to react to the subtlest of cues such as the gentle clinking of dishes, the opening of a door or even a Durrell jumper walking towards the aviary. The result is always the same. By the time you have put the dishes out and raised the whistle to your lips all 16 birds will be lined up along the exterior aviary shelf, begging with their wings open and squawking to express their irritation at having to wait for their dinner. During the afternoon feed, when insects are scattered and hidden in pine cones and under logs, you have the delight of witnessing an ‘Easter Egg Hunt’ as the birds frantically waddle around the aviary trying to be the first to find the delectable wax moth larvae.

Another ongoing study that I was involved with was a pitfall-trapping survey in order to gather information about the choughs’ available food sources. Unfortunately I didn’t have the chance to look into the other end (literally) and sift through chough poo to see what they were actually eating. As I have a weird fascination with invertebrates and had gained some experience in stream-dwelling bugs during my degree, I was appointed the authority on all things creepy and crawly and was instructed to create a pictorial guide to the invertebrates previously found at Sorel. This soon turned into an 80+-page monstrosity that I sincerely hope will be of use to the other volunteers and staff (other than to prop up their computer screens).

It was a challenge at first to identify the unique coloured rings around the legs of each bird, let alone remember which bird the rings belonged to. But after a while you can even guess which birds hang out together and, at the risk of anthropomorphizing our feathered friends, understand their individual characters. The love triangle between Dingle, Chickay and Caûvette (and Caûvette’s incessant whining) wouldn’t be out of place in an episode of EastEnders.

Although you shouldn’t choose amongst your children, Chickay is definitely my favourite. When you watch the choughs for as many hours as I have you see them do some pretty bizarre things. It always seemed to be Chickay that would hang upside-down from the aviary netting like a bat, groom a sheep or chase butterflies with her peculiar waddle.

Reluctantly, my time with the choughs has come to an end. It has been a great experience working on the reintroduction project, and to be part of such an important and exciting project in its infancy. All that is left to say is a big thank you to Liz, Harriet, Glyn, Jenny and everyone at Durrell for making my placement unforgettable. And, of course, thank you to the 16 choughs (you know who you are) that kept me company up on the cliffs. Oh, and thanks of course to the sheep for sharing their best spots to shelter from the rain. I sincerely hope that all the hard work, dedication and frostbite bears fruit once it comes to the breeding season!

Keep up the great work!

By 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.

www.visitwales.com

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 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. 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.

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 at South Stack, Anglesey

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