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Annual Chough report 2023

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Background

Red-billed choughs are considered a rare species in the UK, Ireland, Isle of Man and north west France and, until recently, were classified as locally extinct in the Channel Islands. Changes in agricultural practices decimated their habitat and primary food source, resulting in their rarity. Several other bird species have suffered a similar fate.

Birds On The Edge is a conservation initiative to restore coastal farmland habitat in order to benefit these species. The chough (caûvette in Jerriais) is the flagship for this work and in 2010 Durrell began a captive-breeding programme with the intention of releasing offspring into the wild.

Intensively managed releases between 2013 and 2018, coupled with post-release monitoring and care have resulted in a highly successful reintroduction. The Channel Islands is home once again to a breeding population of choughs.

Notable Events and Successes in 2023

The majority of our breeding success in 2023 centred around our pairs nesting in Ronez Quarry. Interesting observations were noted when checking the nests at the site. There were many more nest spots than usual; which suggested to us that others, perhaps younger choughs, were practicing for when they are mature enough to pair-up and breed. It will be exciting to see if our predictions come true in 2024!

Kevin feeding a chick on the aviary. Photograph by Charlotte Dean.

We recorded 18 chicks in nests within Ronez quarry during the year and one from another location which will be ‘assessed’ in the next breeding season. Fifteen of the total 18 chicks fledged to the aviary. Ten of the 18 chicks are still alive to this day and only two chicks out of the 15 that were blood sexed were male. This being said, due to an issue with the laboratory we use to sex birds, we have nine birds that are currently unsexed and who will remain so until they show breeding behaviour in the future. Given the historic sex ratio skew favouring females, we’re hoping that in 2024 a few more males will be produced.

Table 1, indicating the current population size along with the flocks known sex ratio.

Our only ‘wild-hatched’ pair attempted to nest in a stable during 2023 but were unsuccessful in their endeavours. They subsequently returned to Plemont where they have nested before. While it is believed chicks were hatched, sadly they were never seen at the aviary, suggesting they perished.

The pair of chough that have successfully nested at Simon Sands Ltd. were seen nest prospecting in out-buildings at the airport. This behaviour was dissuaded on health and safety grounds. It is hoped they return to the safer location of the old sand extraction site in 2024.

Impatient choughs awaiting supplementary food. Photograph by Charlotte Dean.

Breeding pair Vicq & Pinel surprised the team this season. They brought one chick to the aviary at the very end of July. This is the first time (to our knowledge) this pair has had a successful breeding season. While there were initial reports of them nesting in a stable building in Trinity, they subsequently chose to nest somewhere else, the location of which is currently unknown. We hope that this will be the start of a successful breeding pair for the future.

The flock has lost a total of nine individuals over the course of the year, but has gained ten new members. Of those choughs that have disappeared, their partners have re-paired up and we hope to see some new successful breeding pairs next season. Overall, it has been a successful year.

Activities in 2023

Primary activities continued as detailed below:

Supplemental feeding

Provision of supplemental food continues daily at Sorel. Attendance by the flock varies seasonally and between individuals. It remains a reliable way to ascertain population size. There are currently forty-seven individuals of which over two thirds are now wild-hatched (Released: 13: wild hatched: 34).

Supplemental feeding allows staff to closely monitor health issues and inter-flock behaviour. Concerns can be flagged up quickly and often dealt with on the spot.

Notable leavers and losses

After forty years of service at Durrell Wildlife Conservation Trust, Dr Glyn Young hung up his boots for the last time in August. He will be enjoying the retired life after much dedication to the Trust. His wisdom and knowledge will continue through the next generation of conservationists who all benefited from his experience.

A picture of Liz and Glyn when the project began!

Sadly, we lost the oldest chough of the flock and one of the two remaining choughs from the project’s first releases back in 2013. Green, although gone has contributed to the population by siring forty-two chicks over the past twelve years; fifteen of which are still alive today.

Green & Pyrrho enjoying the summer heat. Photograph by Charlotte Dean

Research and monitoring

There have been no exciting island-hops for the usual, same-sex pair of choughs to Guernsey this year. Usual visitors to the island, this pair appeared to have broken up, with only one female being observed foraging at Pleinmont. The other female has now found a male worth sticking around for! This could lead to an exciting new breeding pair in the next coming year.

There a few visits to Ronez quarry this year to undertake nest checks. Only two clutches of chicks were ringed in the nest however, as inclement weather prevented other nests being accessed. Subsequent ringing was carried out when youngsters were caught at the aviaries, but three remain unringed at present.

Three chicks in Kevin & Wally’s nest. Photograph by Tobias Cabaret.

We look forward to 2024 when we welcome a PhD student from Anglia Ruskin University to research the choughs for effects of sound disturbance during the breeding season.

Veterinary cases

One of Kevin and Wally’s chicks from last year’s season (Sallow), was found grounded by a local birder in St John. Initially taken to the JSPCA, Durrell ultimately took responsibility for the bird. It was suspected to have a broken coracoid due to the visual bruising in the area; however, this was thankfully not the case. The chough was also seen to have a low platelet count and was underweight. The veterinary team supplied the chough with pain relief and fluids. The Bird Department provided the diet previously used for the captive choughs. Additional food supplements and tasty treats were given to help fatten him up. In our care, the chough gained 20 grams before he was taken back to the aviary. Before being fully released, we had a licensed ringer, ring the chough and then shut him into one of the sheltered sections of the aviary. He was kept here for a few days to habituate once again to his surroundings and for staff to evaluate his flying ability. Once the team were happy with his progress, he was re-released and is still looking happy and healthy to this day.

The remains of a youngster from 2022, Birch, were found at Ronez. Scant remains were collected, so no post-mortem was performed, but rings allowed us to identity it.

Release aviary maintenance

The Sorel aviary is considered a temporary structure for official planning purposes. Permission to keep the structure standing for the next five years was approved in 2023, which means it will be standing until at least 2027.

Storm Ciaran left devastation throughout the island in 2023 and the aviary at Sorel sustained significant but not catastrophic damage. Large holes were ripped in the netting, and aluminium panelling at the side of the aviary was ripped off. Some of the wooden support structures of the enclosure itself were also left weakened and broken.

The aviaries fallen wooden framework. Photograph by Charlotte Dean.

The aviary netting holes require National Trust assistance to help bring our large henchman ladder to the aviary to have the holes reachable to fix. We are working on these repairs between the National Trust and our own staff availability. The wooden framework is a much bigger job which will be fixed at a later date by our maintenance team at Durrell.

Choughs flying over the aviary. Photograph by Abbie Thomson.

In autumn, we secured a grant from the Government of Jersey’s Countryside Enhancement Scheme to fund new netting for the aviary. Thanks to the States of Jersey for this funding, which will enable us to replace the damaged netting in 2024.

Chough report: June 2018

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By Liz Corry

Breeding success

The choughs have been busy ‘behind the scenes’ resulting in a record-breaking breeding season. By the end of June, we had found four active nests with a total of ten chicks. We knew four chicks had hatched at the end of May. We didn’t have to wait long before Ronez Quarry sent photos of a second nest with chicks.

Dusty and Chickay’s nest with three chicks safely tucked away in a quarry building. Photo taken under license by Toby Cabaret.

This nest belonged to Dusty and his partner Chickay: an astonishing and heart-warming sight. This was their third season nesting, finally they had chicks, and from the looks of things they were at least three weeks old.

The icing on the cake is the uniqueness of the coupling. Chickay was hand-reared, proving that our choice of methods worked, and Dusty is himself a wild-hatched chick.

Ronez hired equipment to access the chough nests under license. Photo by Liz Corry.

A site-visit was arranged for 16th June when the quarry was not in operation. Ronez hired a cherry picker to access the nests. What we found was a mixed bag of good news and bad news. Some nests had failed, some succeeded beyond expectations. And then one complete surprise; a nest we had no idea about.

This nest contained one chick approximately four weeks old. We also noticed twigs in a nest-box we had put up in 2014. This is the first time the birds have tried to use this box. Either they decided it wasn’t a suitable place to continue or the pairing just didn’t work out.

The table below aims to answer any queries the dedicated reader has about which pairs succeeded.

Pair Bred before? Nest status
Green & Black Yes empty
Dingle & Red Yes empty
Kevin & Bean Yes 3 chicks
Dusty & Chickay No 3 chicks
Q & Flieur Yes empty
Lee & Caûvette Yes 2 chicks
White & Mauve Yes empty
Trevor & Noirmont No no nest found
Pyrrho & Percy No empty
? & ? – 1 chick
  Total 9 chicks

 

However it also throws up a few queries, like “didn’t Kevin and Bean have four chicks in May”? Yes they did. Sadly one is no more, probably the runt of the clutch, but to have three chicks still alive and well is a first for Jersey’s choughs.

The nest belonging to Lee and Caûvette was found to contain two chicks. Photo by Liz Corry.

You might also be tempted to ask “does the mystery chick not belong to Trevor and Noir“? That, dear reader, is something I still don’t have the answer to a month after the site visit. And one that is driving me insane so lets return to June 16th; life was simpler then.

We had taken a licensed ringer into the quarry with us so we could ring the chicks and get DNA samples for sexing. This is supposed to be done when the chick is around three weeks of age. Clearly from what we were seeing these chicks were older. We did not want to risk disturbing them for fear they prematurely left the nest once we put them back. It is a long way to fall!

That is ok, we thought, we can just ring them once they reach the aviary. We can see which adults feed them and work out ownership that way.

How naive we were.

Fledged chough chicks reach the aviary

Below is a montage of footage taken during the supplemental feed once the chicks had fledged. Imagine having a baby that can fly and walk and scream for food whilst doing said actions. Then multiply by two or three. That is what it’s like for a chough parent for the first few months. Note how loud the begging starts off then trails away. Always lingering, never stopping.

From appearances, Chickay was not keen on parenthood. She left most of the feeding duties to Dusty. One of our daily reports records an observation of Kevin “karate kicking” a chick in response to the constant in-your-face begging. Quite often at the feeds you would see chicks accidentally push the parent off the food-stand or shelf in the frenzy to beat its sibling to the food on offer. You also saw them beg at non-breeding individuals who looked more than a little perplexed by the situation.

Throughout all this, the three newbies (Han Solo, Chewy, and Skywalker) remained locked in quarantine in one half of the aviary. We could not attempt to catch-up and ring the wild chicks until the three had been released. That was scheduled for July.

All we could do in the meantime was try and figure out how many chicks each set of parents had. Lee and Caûvette made things easy as they continued to visit Les Landes and Grosnez, taking their chicks away from the mayhem for a few hours each day. We knew both of their chicks seen on the 16th had survived and arrived at the aviary the last week of June.

Family portrait: Lee and Caûvette with their two chicks at Grosnez. Photo by Mick Dryden.

Lee with his two noisy chicks. Photo by Mick Dryden.

Dusty and Chickay were tending to three chicks (well Dusty was at least). They would take them back and forth between Sorel and the south-east corner of the quarry. Initially there was concern over one of the three chicks as it looked relatively lethargic. We put this down to the heat and that it could be the youngest, struggling to keep up. Dusty was always very sensible, taking his chicks into the shade to rest.

Dusty and Chickay keeping their chicks in the shaded parts of the quarry. Note the chick lying down next to dad whilst the other two preen next to mum. Photo by Liz Corry.

Kevin and Bean‘s three also made it from nest site to Sorel. However, they made it a little harder. Most of the time their chicks were kept around Sorel Point. Often out of sight, but not earshot. 

View across the quarry from Sorel Point. Photo by Liz Corry.

Then the mystery deepened. Q and Flieur turned up to the supplemental feed with two chicks. “But their nest was empty?” you cry. Yes, yes it was. “And the surprise nest only had one chick in it?” you answer back. Yes, yes it did.

The Plémont pair

Earl and foster-reared Xaviour, or the Plémont pair as we call them, are still roosting out at Petit Plémont. Their amazing choice of nest site has made it impossible to tell exactly what they have been up to this breeding season. We did suspect, from the couple’s behaviour out of the nest, that the female was incubating eggs.

Earl taking a break on the WW2 bunker ruins at Petit Plémont. Photo by Liz Corry.

One was seen carrying something white away from the nest. An optimistic observer thought it was a faecal sac. These ‘sacs’ are produced by chicks and carried away from the nest by the parents. He changed his mind when he saw the adult pecking away at it. The white object started to look more like an egg, but smaller than a chough egg. Out of reach of the observer, we will never know the true-identity of the object.

In the days the followed, hope of a successful nesting attempt began to fade. Xaviour was spending more time away from the nest. Foraging around the headland and neighbouring cliff tops to feed herself rather than take back to an expectant nest.

The pair are young. This year should be taken as a positive step forward in their development. They remain the first pair to set up a territory away from the release site. As they mature they will no doubt see success with their nest.

Star Wars saga continues

Han Solo, Chewy, and Skywalker continue to adjust to life at Sorel whilst in quarantine. Faecal samples from the two Paradise Park birds tested positive for nematodes.

Staff began to hear sneezing from the confined group a week or so after their arrival. Nothing to cause alarm, but enough to warrant a wormer pre-release.

This was scheduled for 20th June. On the 17th the Bird Department received a call to say that there were only two choughs locked in the aviary. Skywalker was missing. Scanning the aviary, it became apparent that he had not used Jedi mind tricks to escape. He had in fact managed to squeeze out through a hole in the netting, no doubt created by rodents.

He was not with the free-living choughs at Sorel. Well not in plain sight at least. The following day he couldn’t be any more obvious if he tried. Skywalker was on the roof of the aviary alongside Zennor a young female.

Since the boys arrived at Sorel, Zennor has shown a keen interest in them. She sits, on the opposite side of the netting during every feed whilst everyone else is tucking into their meal. We thought her interest was in Han Solo as they had touched bills through the netting; fiction becoming reality? Alas, it was Skywalker she wanted which worked to everyone’s advantage as he had another chough to follow, returned to the aviary, and we managed to get him safely back inside.

Return of the Jedi: Skywalker shortly after being trapped back inside the aviary. Photo by Paul Pestana.

All in time for the vet to visit on the 20th, give all three a wormer, and fit Han Solo with a transponder chip just like all the other captive-bred birds have. Bird Department staff also kitted them out with shiny new leg ring combos to make it easy to tell them apart once released.

Luckily the States Vet agreed that no extra time needed to be added to their quarantine period. Once complete, at the end of June, they can be released.

May the force be with them.

Aviary maintenance

Despite the recent rodent-proofing at the release aviary there are still weak points in the defences. As exemplified by Skywalker’s escape. Without a major overhaul of the aviary design there is not much to be done.

Mind you, that overhaul may come sooner than imagined. The shelving has now warped so badly that bolts keeping the hatches closed no longer reach. The hinges on the external keeper door snapped right off due to rust.

This is the first year the pre-release group have not had full access to the flight tunnel in a bid to avoid further premature releases. Once the new boys have been released and settled into life at Sorel we can start repair work.

Supplemental feeds

The choughs have seen a few changes to the menu this month due to food shortages. There is still no Remilline pellet in stock in Jersey, so the egg-based diet returned to the menu. The live-food manufacturer has been experiencing issues with their mealworm stock resulting in fewer or no insects being delivered. Not the best of timing. We had to increase the amount of supplemental food this month in response to an increasing demand. Obviously with mouths to feed, the breeding pairs become more dependent on the aviary feed.

Lights, camera, action

Ronez Quarry very kindly funded young film maker Sam Hertzog to fly to Jersey and produce a short film about the chough reintroduction project. Sam had four days to try and sum up the last five years into a seven minute documentary. To make the challenge that little bit harder we threw in rolling sea fog, a field manager dying of hay fever, and birds that never paid attention to the script.

Sam succeeded. You can view his film below. We are very grateful to his friend Elin Cunningham for proposing the idea and for being the boom operator, gaffer, assistant director, chauffeur….

Chough report: July 2017

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One of this year’s wild-hatched chicks arriving at the aviary. Photo by Liz Corry.

By Liz Corry

Fledging news!

Previously on Choughs…cue theme music…On 27th June Beanie baby was the first of four wild chicks to appear at the aviary with parents, Kevin and Bean, by its side.

Six days later another chick arrived. Unringed, but accompanied by Green and Black, and sneezing and wheezing, so it wasn’t hard to determine which nest it came from. It wasn’t hard to find a name for the new chick either. Lil’ Wheezy, who clearly wasn’t well, but it had made it to the aviary, so it’s odds were looking up.

A wild-hatched chick arrives for the first time at the aviary with parents begging for food. Photo by Tanith Hackney-Huck.

The third chick made an appearance on 5th July. We knew which nest it came from because of we could see pink and black leg rings. We didn’t know who it’s parents were. Well, not until it started guzzling food down its throat provided by Lee and Caûvette. This meant that our Les Landes pair had been travelling 9km away from their nest and the group finding food for their chick.

The news of this chick also means that another of our four hand-reared choughs has successfully bred in the wild; Dingle (fathered two in 2016), Caûvette and Bean. Poor Chick-Ay has yet to find a dedicated partner.

The fourth and final chick was spotted flying around the quarry on 6th July. Again, we knew which nest it was from, but did not know the parents. Two days later we were in for a pleasant surprise. Q and Flieur, a new pairing, led their chick over Sorel Point to join the flock feeding at the aviary.

This now brings the total number of free-flying choughs in Jersey to 38. Almost a quarter of which were wild born in Jersey. There is a video of the group in flight on Jersey Zoo’s Instagram page or just click here if you don’t have an account.

Lil’ Wheezy gets wormed

We needed to worm the sick chick that was now visiting the aviary twice a day. It couldn’t be done straight away. We needed the chick to become accustomed to flying in and out of the aviary in order to trap it inside. It took a good week for Lil’ Wheezy to grow in confidence and fly all the way in at each feed.

A wild fledgling caught up under licence to treat for nematodes. Note the bill colouration due to its young age. Photo by John Harding.

Patience paid off on the 19th when the team were able to trap it inside and catch under licence. Dave Buxton fitted leg rings and the Vet gave it a wormer before being released back to it’s parents and the rest of the flock.

Classic reaction to a vet holding a needle. Photo by John Harding.

MSc project wraps up

Guille finished collecting data for his research at the end of this month. He now has the delight of returning to Nottingham Trent University to make sense of it all. I will let Guille explain in his own words…

“Birds, and other animals have personalities. Consistent behaviours that are different between individuals, maintained through time and favouring -or not!- the survival of the individuals and their successful breeding.

Studying the boldness-shyness continuum in choughs. Photo by Liz Corry.

With the choughs I am looking at a classical behavioural trait: the boldness-shyness continuum and how it might affect survival.

Basically, if you are a bold bird you may be good at defending your food patch from others, get stronger and healthier and be able to feed your nestlings properly. However, if you are a very bold bird that would not leave the food patch even when there is a falcon approaching, you are in serious trouble.

I want to see if we can predict how far the released choughs will go to find food everyday just by looking at their personalities. Some studies have already shown that boldness has an effect on habitat use and distance travelled, which may be useful in a project like this one, where every bird is highly valuable and the distance they will travel will increase the chances of finding more food, or getting lost! If a correlation is found, it would help the project team to select which birds should be released depending on what behaviour is best to assure survival in the area.

Does Lee’s personality type predispose him to travel several kilometres away from the release site to feed? Photo by Mick Dryden.

For assessing their boldness, I presented them a squirrel-proof bird feeder that they had not seen before, as they have their daily supplementary feeding in open trays. I recorded the latency of each bird to pick food from it for the first time, during 15 minutes. After that, they were given their daily meal and I would not repeat the test until approximately ten days later, so they would not get used to it. Finally I gave every bird an average boldness score based on how long they took to pick food for the first time.

This year’s wild chicks were clearly not shying away from the feeder. Photo Guillermo Mayor.

Assessing the distance travelled was the fun part, as they had lost their radio tags. I had to become another chough and follow the group during their morning stroll. They leave the roost by 5am, returning for the 11am feed. I learnt lots about chough behaviour in the field. I saw their games, love arguments, gang fights, first trips of their chicks, but still they are very complicated birds.

By the end of July, after having cycled every single track of the north coast, I had a bunch of observations, from which I would pick the furthest point from the roost I saw each bird. Some of them were a bit surprising, such as Trevor and Noirmont. I found them perching on a German WW2 cannon, south of Les Landes. They looked like nobody could mess with them. I would definitely keep an eye on those two.

The two and a half months passed too quickly and I wish I could have stayed longer. The support I received from the project staff was amazing, and I would definitely recommend anyone that has cool ideas that would help the project and the broad bird recovery knowledge to think about doing some research here.

I am currently in front of the computer, missing the field and the choughs, and for now it seems that the boldness was consistent, which is good news! I really hope I can come back soon and see the noisy choughs again soaring over the windy cliffs, and all the lovely people who were like a family for a summer.”

Birds On The Edge wins a RHS award

BOTE award 001 (2)

Birds On The Edge received a Silver award in the conservation section of the annual ‘Parish in Bloom’ event, a hugely popular and well supported national floral competition held under the professional auspices of the Royal Horticultural Society.

Glyn Young met the judges and Mike Stentiford on Sunday 23rd July to show them around Sorel to see the grazing flock of sheep, conservation crop fields, and the choughs. Although only two choughs showed up!

More information about the Parish in Bloom event run by Natural Jersey can be found at http://www.parish.gov.je/Documents/NatJerBrochureA4_ParishSites.pdf.