by Liz Corry

The first release of this year’s captive bred choughs got underway on the 21st July. Six two-month old chicks from Durrell Wildlife Park were released from their aviary at Sorel to join the current flock of twenty four free-living choughs.

Adults and chicks enjoying the summer weather on the cliffs at Sorel. Photo by Liz Corry.

With more birds outside the aviary than inside, including four very loud wild chicks, the release cohort had more of a ‘hard’ release than the gradual introductions of 2014. The hatches were opened in the late afternoon much to the bemusement of the inhabitants. Once all thirty had mixed and mingled they were called down for food at the aviary, and then left to get on with it under the ever watchful supervision of the field staff.

Recently released chicks joined the free-living group for flying lessons. Photo by Liz Corry.

The release cohort is a mix of parent-reared and foster-reared birds which meant they had two different approaches to the ‘outside’ world. The parent-reared chicks had a tendency to follow the adults which meant they quickly learnt where the best foraging sites are, where to shelter from the rain, and how to react to potential threats most notably the peregrines. The foster four were not quite as willing or confident and tended to look to their foster parents for support.

A foster-reared chick doing its part for the Jersey Butterfly Monitoring Scheme. Photo by Liz Corry.

After the first evening flying at liberty around Sorel the six chicks returned to the aviary along with a few older birds and went to roost. The excitement of it all must have taken it out of them as the birds went in almost two hours before sunset and didn’t leave again until the morning.

Sunrise at Sorel: A panoramic view of the release aviary. Photo by Liz Corry.

Staff returned at sunrise to find one group of choughs breakfasting over on the other side of Mourier Valley. The begging calls of the wild chicks carried over the valley giving away their location.

The begging calls of the wild chicks carried over the valley giving away their location. Photo by Liz Corry.

Whilst another group were by the cliff path at Sorel. The foster chicks were at the aviary. On seeing their ‘parent’ (i.e. me) arrive over the brow of the hill the flew out to warmly greet and/or demand breakfast off her. This also involved landing on said parent’s head and backpack.  At first this behaviour was very concerning. Would they behave like this around other people? Are they going to be naive when faced with potential threats?

The foster reared chicks had to take things one step at a time when it came to the release. Photo by Liz Corry.

Over the next few days the chicks were put to the test by undercover bird keepers and unsuspecting public. They even had a few peregrine encounters. They passed every test and demonstrated how intelligent corvids really are. The foster four can identify their ‘parents’ from fifty metres away and will fly straight over to greet them. Or to be more exact if they think they can get an easy meal out of us. However, if we are with other people they won’t come near. As they grow in age and confidence and begin to find enough food to support themselves they should start to depend less on their foster parents.

Their young age is apparent not just by their behaviour, but by their physical appearance. The youngest chicks have a grey-yellow bill. Those a few weeks older have an orange colouration which should develop into the trademark red bill in another month.

A two-month old chough discovering the tasty morsels life in the wild has to offer. Photo by Liz Corry.

There are now thirty choughs flying free on the north coast of Jersey. It won’t be long before they start exploring and making appearances in other parts of the island.

Will the choughs decide to visit the newly restored Plemont headland this year? Photo by Liz Corry.

by Liz Corry

“The Guide says there is an art to flying”, said Ford, “or rather a knack. The knack lies in learning how to throw yourself at the ground and miss”.
― Douglas Adams, Life, the Universe and Everything.

Wild and captive-bred chicks fledged and took flight this month. Photo by Liz Corry.

July was the month of learning and adventure for the captive-reared and wild-raised chough chicks at Sorel as they spread their wings and took the air for the first time. Fledging at the beginning of the month and, for the captive chicks, release into the wild before the close. And I’m happy to add that they landed on the ground safely.

Captive-reared chicks

The four foster chicks locked in the release aviary had already started stepping out of their nest-box and exploring their surroundings during feed times. In between they would hop back inside, preen and chat amongst themselves before falling asleep until the next feed. A simple life we all envy.

As they got older they spent more time exploring and by the 5th they had been given access to a section of the poly-tunnel to practise short flights and learn to fly to target areas for food. Weaning them off hand-feeding followed the same pattern as previous years although these four were less willing to find their own food than previous chicks.

Weighing the foster-reared chicks. Photo by Liz Corry.

The two parent-reared chicks at Durrell joined them on the 7th. They were caught up, given clearance by the vets, and transported to Sorel by keeper Jess Maxwell and student Bea. These chicks are two weeks older than the foster chicks and, therefore, a bit more independent by the time they arrived at the release aviary. That being said, at two months old they still have very strong associations with their parents and depend on them to bring most of their food.

Parent-reared chicks from Durrell moved to the release aviary at the start of July. Photo by Liz Corry

Separation from their parents and the move to an unfamiliar environment  meant they were naturally stressed upon arrival. They appeared to adapt quite quickly though, finding food bowls in the aviary and some level of solace from the chough flock calling outside of the aviary.

After a day to adjust, they were mixed with the foster chicks and the group given access to the entire first half of the aviary. A week later they had the whole aviary to themselves and the free-living group were locked out. Observations before the move confirmed that no one was using the aviary as a roost site anymore so no one was being cheated out of a secure night’s sleep.

Chicks inside the aviary feed alongside those outside. Photo by Liz Corry.

Target training the captive chicks in preparation for their release was a challenge. The parent-reared chicks wanted to be with the free-living group. They could see and hear the wild chicks being fed by their parents just metres away and wanted in on the action. They also didn’t want to go down to the target areas on the floor as they had little trust in the people putting the food out. The latter was solved by setting up a target area on the shelf between the captive chicks and free-living group. This way the chicks could get to food straight away and start associating the sound of the whistle with the arrival of the adults and food.

The foster chicks on the other hand had no problem with going to the food. Just as long as the people putting out the food stayed with them. Their behaviour changed from curiosity over the ‘outsiders’ whilst in the nest-box to abhorrent fear of twenty-four noisy choughs descending en masse at feed time. Opting to hop in to a shelter-box and act all nonchalant or just go for a nap in between feeds.

Adults arriving at the aviary in anticipation of an early feed. Photo by Liz Corry.

Trying to target train the chicks in between feeds, when the free-living group had left, was not successful either. The pressure on the parents to find food for the wild chicks meant they kept a keen eye on the aviary. Any hint that the keepers were going in or even near the aviary with insects for training and they would be over like a shot.

With time the foster chicks grew in confidence and started to eat alongside the adults and the parent-reared two settled down a bit around the keepers. Did they finally succeed in their target training? The ultimate test is always once they are outside of the aviary when they get released.

In the meantime…

Durrell’s breeding pairs return to their flock

Tristan and Iseult had a few days to adjust to the loss of their chicks followed by revelling in the peace and quiet of not having something insistently follow you around begging for food, before the other two pairs were moved back into the display aviary for the non-breeding season.

Gianna also moved back on show to join the flock, promptly ignore then, and turn her attention to her adorning fans (at least that’s how she views the public and keepers). This year she has the added enrichment of Durrell’s new keeper talks. Three times a week she has an audience to play to whilst we explain the important role the captive choughs have in the re-introduction project and Birds On The Edge.

Quarry capers

Viewing point in Ronez quarry used for observing chough nests. Photo by Liz Corry.

The wild chicks left their nests in the quarry sometime around the very end of June and first few days in July. As all choughs chicks do at that age they spent time exploring their nest sites, i.e. inside the quarry buildings, before making an appearance outside. The parents could be seen taking food back to their respective sites, but not always venturing inside. On one occasion Dingle or Red went to the staircase at the side of the building, perched at the doorway (opposite side to the nest), and started feeding something. Presumably her chick and not one of the quarrymen. We were able to record this activity because Ronez Quarry kindly gave staff access to the viewpoint. Our vantage points from Sorel or the Ronez loop road would not have had the same line of sight.

Once the chicks had ventured outside it was a bit easier to track their movements. They were the choughs that stayed on the buildings when every other chough flew away to the aviary for supplemental feeds. White and Mauve’s two chicks had a tendency to walk back into the building once their parents had left. Who can blame them with black-backed gulls nesting close by and the juvenile peregrines having introductory lessons on how to hunt in and around the quarry.

Two wild-hatched chicks making their first appearance in the quarry. Photo by Liz Corry.

Green and Black continued to return religiously to their nest site, often carrying food. The debate over whether or not they still had a chick was fuelled further when a fledgling was spotted on the roof of their building. Was this the fifth chick or was one of the other four making its way out of the quarry one building at a time?

The answer came when the chicks made their first flight out of the quarry. On the morning of the 4th four chicks were spotted at the bottom of Sorel Point with the other choughs. Lee, released last year, was observed pulling at the tail of one of the chicks. Not your typical welcome greeting. By the afternoon they had followed the flock to the aviary and were merrily feeding and begging and feeding and begging and feeding…

Dingle, a hand-reared bird, with one of his wild hatched chicks waiting for supplemental food. Photo by Liz Corry.

Mauve with one of her two wild-htached chicks at the release aviary. Photo by Liz Corry.

Anyone with experience of wild choughs will know how loud and incessant chick begging can be. And it lasts several weeks much to the dismay of the parents. Green and Black did not have a chick with them. Hopefully not having to participate in the cacophony of chick begging was some sort of consolation to them.

A wild chick being fed the supplemental diet by a parent outside the aviary. Photo by Liz Corry.

Veterinary intervention

Black was not in the best of health anyway. We had noticed for some time that she was returning from the quarry sneezing. Her symptoms started to worsen as fledging time approached. We intervened on the 6th after managing to get an individual faecal sample from her in the wild.

To catch her in order for the vet to administer drugs we tried trapping the group in the aviary at the feed. Normally this is an easy task, but the presence of the wild chicks meant that the chough families were on high alert and scarpered at the first sign of a staff member approaching the release hatches. The only two birds we could lock in before they had time to realise were Black (because she was ill) and Flieur.

This turned out to be useful as Flieur had lost her colour ring a couple of weeks prior so a replacement was fitted and she was released. Black was caught up, weighed, treated and released. Her breathing was very laboured and the worst we have seen to date. There was potentially a need to give a follow up wormer in two weeks times. Normally treated choughs stop sneezing within a day or so and don’t need the second injection. Black continued sounding rough for a week before clearing up. As always we observe daily and submit group faecal samples to the vets once a month to monitor the birds’ health.

Dusty, Egg, and Chickay

The nest site discovered in June potentially belonging to Dusty and one of his females failed to produce anything. Not too surprising as all three are quite young and it was their first attempt. Dusty and Egg continued taking food from the aviary to the quarry. Chickay remaining faithfully by their side feeding and preening Dusty when asked. As with Green and Black it would appear they were simply caching food for themselves away from the flock. Very sensible as competition grew over food bowls at the aviary in response to an increased demand for food.

Summer finally arrived…for a day

The 19th July saw temperatures in the aviary reach 34°C and the hottest July in Jersey. In fact the third hottest day since records began. Extra water trays were provided at the aviary. For the public the sight of sunbathing choughs might have appeared quite alarming since they often look like they have just been shot and fallen from the sky. They are just making sure every feather gets a piece of the UV action and any feather mites zapped out of existence.

A sun-bathing juvenile chough. Photo by Liz Corry.

Their main struggle with the weather was the fact that Sorel had not experienced much, if any, rain for a few weeks. With no shade cover or water the sun-baked ground had hardened to the point of cracks appearing. No chance of getting to any insects in the ground, assuming there were any. The sheep dung was also absent of insect larvae. Wild food resources for the choughs had become depleted and their dependency on the supplemental feeds increased. The effect it had on the flock added an extra challenge to the 2016 chick release.

The heat also appeared to have an effect on humans and their awareness of their surroundings. Scorch marks on the dry grass land at Sorel and Devil’s Hole show that people have had disposable barbecues and in one case a log fire on National Trust Land. The latter is illegal. There also seems to be an increase in the number of cigarette ends left around the site. With sun-parched grassland and heath these activities can be extremely dangerous. Exemplified by an incident at Grantez in which memorial bench was badly burnt when somebody left a used disposable BBQ under it.

Disposable barbeque damage to a memorial bench on National Trust land in July. Photo by Jon Parkes.

Preparations for release

As well as target training the captive chicks for their imminent release, staff worked on preparing the aviary. Simple tasks of oiling locks and hinges turned into DIY repairs to replace hinges and framework. A spot of up-cycling turned a pallet board and reclaimed wood from Durrell’s wood skip into steps and benches so keepers could securely reach the hatch locks. In the past we relied on conveniently placed logs and rocks. Not necessarily health and safety compliant, made worse by wear and tear over the years. The added bonus of the new additions was their unintentional enrichment benefits for the choughs.

The bracken started to fight back against the sheep this month. Photo by Liz Corry.

The biggest task was clearing the bracken from the embankment to allow the choughs to see from inside the aviary over to the grazed land. This helps with the release and provides an extra area for them to forage close to the aviary. This time of year the bracken reaches record heights in some places towering above both sheep and people. Removing the bracken by the aviary revealed a few desiccated toads and opened up areas for a slow worm and the occasional green lizard. It also meant the rats had fewer places to hide.

Bracken clearance alongside the aviary provided extra foraging ground for the choughs as well as a clear view. Photo by Liz Corry.

The aviary netting started to get to a lot of unwanted attention from rodents once the hatches were closed off to hold in the captive chicks. With no obvious way in and out to get to any spilt food left by the choughs the rodents took to chewing holes in the netting. The battle is ongoing with the rodents favourites to win.

Rodent activity in and around the aviary creating problems with the netting. Photo by Liz Corry.

Final preparations

Before take-off, the chicks need a clean bill of health. On the morning of the 19th chick V was missing from the melee that is breakfast time. A quick search of the aviary found her perched in one of the shelter boxes holding her head back and to the side. She wasn’t saying much and didn’t come for food straight away. With a bit of coaxing she came down and walked along the shelf to the food and the other chicks. She half halfheartedly begged and ate a mealworm then shuffled off into another shelter box.

Chick V was under the weather on the 19th, but perked up on hearing the threat of a vet visit. Photo by Liz Corry

Close, very close, observations of her throughout the morning showed no change and a tendency to hold her neck awkwardly. The Vet visited in the afternoon to examine her. She had perked up by that point (as animals always do when they know the Vet is on the way), yet still not 100%. With nothing obvious to diagnose a blood sample was taken and sent off to the lab. We had a two-day wait before hearing she had the all clear. By which time she was back to normal and understandably a little cautious around keepers.

Congratulations it’s a boy, and a girl, and another girl, and a boy….

The day after the vet visited we heard back for the diagnostics lab regarding the sex of the 2016 chicks. We now know that the foster four are all female and the parent-reared zoo chicks are both male.

In the wild we have a nice 50:50 split. We have a question mark over one of the samples so we cannot be 100% sure without taking another blood sample. Looking to tarsus (leg) length as an indicator it suggests the individual is female. If it turns out to be male then we have three males in total hatched in the wild this year.

Operation Chough

Paradise Park successfully raised ten chough chicks this year including two hand-reared. Once they have their sexing results they will work out which chicks can be sent over to Jersey to take part in the release. The plan is for the Durrell chicks to be released as early as possible to learn what life is like outside the aviary and acquire skills. When the Paradise Park choughs arrive we will call the Durrell chicks in to the aviary and lock the group in together whilst the UK birds fulfil their quarantine requirements.

After which point, the two groups will have socialised and formed relationships or at least connections. Once released, the Paradise Park chicks will hopefully follow the Durrell chicks and learn from them.

Paradise Park established Operation Chough in 1987. Our partnership since 2010 has now helped their objective to come to fruition. With the second release this year involving their chicks, Jersey’s free-living flock could reach a total of 36 individuals.

by Liz Corry

Update on the Durrell chicks

The four chicks being foster-reared in Gianna’s nest-box. Photo by Liz Corry.

At the end of May the four hand-reared chough chicks at Durrell were transferred to Gianna’s nest-box so she could help feed and look after them.

We moved them in once they reached five days-of-age. Since they hatched on different days it meant the moves were staggered. This probably helped Gianna as it meant she went from having four eggs to one chick and three eggs, followed by two chicks and two eggs and so on.

We continued to feed the chicks five times a day whilst making sure there was enough food for Gianna to cover the other feeds. The Go-Pro video below gives you a close up insight into feed times in the nest.

Normally once the chicks start to open their eyes we start wearing a black glove and feed with red tweezers. A poor imitation for a chough, but it seems to help the chicks. It means that when they are older and out and about at Sorel they are still going to be wary of people. We faced a problem with our ‘no glove, no love’ policy this year. Gianna hated the glove.

Gianna in front of her nest-box with four hungry foster chicks inside. Photo by Liz Corry.

For some reason she took great offence and would attack your hand or even just the glove if it was left on the food stand. She was the same with the latex gloves we had to wear to take DNA samples from the chicks. We tried to be secretive about using the glove, even tried distraction tactics with a second person preening Gianna. However, she quickly wised up to our actions.

Gianna overseeing two of the chicks weigh in sessions. Photo by Liz Corry

As the chicks grew and developed we reduced the amount of feeding we did and let Gianna do the majority of the work. We regularly weighed the chicks to make sure they were progressing well. The video below demonstrates how we weigh them and more importantly how attentive Gianna is, not to mention how comfortable she is with what we have to do. Apart from the initial settling-in period as mentioned in May’s report the chicks seemed to have no issues.

At three-weeks-old we added leg rings, took measurements, and DNA samples for sexing.

Student Bea holding a three-week-old chough chick in preparation for leg ringing and DNA blood sampling. Photo by Liz Corry.

Flight feathers emerging on the young chicks. Photo by Liz Corry.

We started to notice the younger chicks had feathers missing. It was subtle at first since they were still growing feathers and had naked areas.

Very quickly it was clear that Gianna was too attentive, she was feather plucking. She had shown signs of this with the chick she foster-reared last year. Back then it was only the small feathers under the chick’s chin and it stopped once he had fledged. This year she had intensified and focused on the wing coverts.

The chicks in themselves were fine and she was still feeding them as normal, but we couldn’t leave them in there until post-fledging. Birds without flight feathers don’t tend to do so well when released into the wild. It meant we had to move the chicks to Sorel earlier than planned and take back full responsibility for feeding the chicks.

Gianna was not too pleased and took a day or two to adjust. The chicks, however, coped really well. They settled into their new surroundings locked away in a nest-box in one section of the aviary.

Panoramic image showing the nest-box (right) in the release aviary and the section where the chicks will be kept separate from the free-living choughs who still use the poly-tunnel. Photo by Liz Corry.

The oldest chick could be heard calling in response to the free-living choughs when they showed up at the aviary which was a positive sign. We immediately started using the black glove and red tweezers for every feed.

The foster reared chicks in their nest-box in the release aviary. Photo by Liz Corry.

The chicks very quickly started to behave and look like proper choughs once they were five weeks old. The oldest chick, known for now as Chick U, would come to the front of the nest to try and beat the other three to the food.

Chough chicks start exploring their nest site around four to five weeks of age. Photo by Liz Corry.

Understandably U was also the first to leave the nest on 30th June. U jumped out to the shelf were the pot of food was and begged to be fed. Once it realised the other chicks in the box were still getting food it jumped back in. Chick U was very quickly followed by the other three on the same day. Their motivation to leave was completely food driven. As soon as I arrived with the food at 07:30am U jumped out to beat the queue. By the afternoon feed Chick W had realised U’s game so jumped out behind and within seconds the other two, Chick X and Chick V, took a leap of faith in despair that they might not get fed otherwise.

Captive chough chicks out of their nest. Photo by Liz Corry.

Now feed times are slightly chaotic as we have mobile begging chicks and everything is new and of interest to them. From their first water tray to small things like screw heads in the aviary timber. They won’t fly much just yet, its all about jumping and walking and occasionally misjudging and tripping over.

They are taking a real in interest in the free-living choughs on the other side of the mesh. This is obviously very advantageous for when they are finally released and mix with the group. They will be learning about the social structure of the group and observing all their behaviours. Hopefully becoming less dependent on staff, but still comfortable in their presence to make management practices easier.

Next month they will be joined by the parent-reared chicks from Durrell. Another new learning experience to embrace.

Tristan with one of his two fledged chicks at Durrell. Photo by Liz Corry.

Chough chicks have a habit of jumping out of the nest at six-weeks old to explore and feed then going back inside to take naps during the day. Photo by Liz Corry.

Chicks S and T took their first brave steps out of the nest-box back at Durrell this month. The proud parents stuck close by their chicks. One chick didn’t take to outdoor living as much as the other and went back in the nest for a bit.

Visitors at Durrell will only have a short window of opportunity to see the family out and about in the aviary. Once the chicks have started eating for themselves they will move to the release aviary and start socialising with the foster chicks.

One of the parent-reared chicks having just left the nest at Durrell. Photo by Liz Corry.

Update on the chicks in the wild nests

The chicks in the wild nests have also had an momentous month. At the start of June we made the visit to the nest sites to ring the three-week-old chicks. Glyn and Bea were joined by Channel Islands ringers Dave Buxton and Cris Sellares. Donned top-to-toe in industry standard PPE they ventured down into the quarry.

The first nest site they visited belonged to Red and Dingle. When we checked in May they had two chicks and much to everyone’s relief they still had two chicks. Except much bigger and a lot noisier.

Chick PP004 from Red and Dingle’s nest being fitted with a metal leg ring. Photo by Bea Denton.

Each chick was fitted with a metal Jersey leg ring, colour plastic rings for quick visual identification and had leg, wing, and weight measurements recorded. Small samples of blood on blotting paper were taken for DNA sexing. We should know by July which are male and which are female.

Cris Sellares with chick PP005 sporting pink and orange leg rings. Photo by Bea Denton.

Next was the turn of White and Mauve. They also had two chicks the last time we checked and two unhatched eggs. We are pleased to say both chicks had survived. As expected the two eggs had failed and the parents had removed them from the nest.

Chick PP003 having it’s wing length measured. Photo by Bea Denton.

One of these chicks proved to be a little tricky and lost a claw. A spot of super-glue was applied to stop the bleeding before it was placed safely back in the nest.

Chick PP002 sporting its new red and white striped leg ring to let people know it hatched in Jersey. Photo by Bea Denton.

The last nest to be visited was Green and Black’s who actually started nesting first out of the three pairs.We could not reach their nest last time, but had heard a chick or maybe two chicks begging. This time we were told by a member of the Ronez team that a chick had been seen on the floor of the building a day or two before. The ringing team searched the area below the nest. Glyn found several pin feathers on the floor. The nest was eerily silent.

With very little to go on and no access to the nest we do not know if the chick fell out and died or had died in the nest and the parents discarded the body. The feathers could be a result of predation, but did this happen before or after the chick had died?

Green and Black have not been behaving any differently around the aviary. They still showed up for food and had continued to fly back towards the nest site with food in their bills. We continued to monitor them all month and nothing changed. We may have given ourselves false hope. Did the nest have two chicks the first time we checked? Has only one died and the parents are still feeding a second? We will have to wait until after fledging to see if Green and Black are indeed feeding an unringed chick.

The wild chicks were due to start leaving their nest in the last week of June. From the behaviour of the parents we think this happened. However, with the persistent rain and fog there have not been many nice days to emerge from the warm, dry buildings and  properly practice flying for the first time.

Watching the quarry to spot the first signs of fledglings. Photo by Liz Corry.

We have been very grateful to our old colleague Paul Pestana who has volunteered his time to help watch the nest sites. Combining all our observation notes we think we have exciting news for the July report.

Mystery fourth breeding pair?

Green and Black’s nest was not the only mystery at the quarry this month. Shortly after the visit to Ronez I was contacted by Robin Jenkins to say that one of his site foremen had spotted a nest in another building. He had noticed it because the building is regularly used by a few choughs as a roost site.

I went up at 6:45 am to check it out before the machinery was switched on. There were no choughs to be seen or heard. However, there was a nest! Trying to look into the nest with a Go-Pro on a fishing rod let me down once again. This time because the camera has no light attached. Torchlight was only possible side-on. There were no sounds coming from the nest in all the time I was there dangling a camera above the nest. However, there was fresh evidence of choughs using the building. I suspect an inexperienced pair attempted to build a nest. They might have stopped at the nest building stage. We don’t know if the nest is lined, it could just be made of twigs.

Post-modernism industrial art or a fourth nest site? Photo by Liz Corry

A return visit to the quarry at the weekend when everyone had gone home answered one question. The birds using the building were Egg and Chickay who are two-year-old females, one parent-reared, the latter hand-reared. And the male they are partnered with is no other than our infamous wild-hatched chick Dusty!

Chickay (left) with Dusty and Egg appear to have found their own corner of the quarry to set up home. Photo by Liz Corry.

The trio then added to the list of questions by disappearing into another restricted access building with food. From our observations we know they regularly take food back from the aviary to the quarry. Neither female has shown signs that she is/was incubating. Are they just caching food away from the other choughs? Is this what Green and Black are doing?

All we can do is keep monitoring the choughs and keep a lookout for any unringed juveniles being fed at the aviary in July.

The grazing flock

Less of a mystery is why the sheep at Sorel have gone from being cream coloured to brown. Its sheering season. Time to throw off their winter coats and prepare for a sizzling hot summer. Any volunteers willing to knit the sheep coats whilst they wait for summer to show its face please contact the shepherd.

The flock was temporarily locked in the aviary field and adjacent field whilst Aaron and Ewen processed them all. The sheep had a field day (pun intended) eating their way through the long grass. It is now at a height perfect for chough bills to start foraging for insects.

Towards the end of June the sheep moved back onto the headland where they are free to roam and continue working on restoring the habitat.

Fundraising support

The 2016 Collas Crill Island Walk with the Rotary Club de la Manche was held on 18th June. Inevitably the 48-mile round-the-island route includes the clifftop home of the sheep and the choughs. We were delighted to hear that Durrell are one of the many local charities who will receive money raised by the several thousand participants.  Durrell will put these funds directly into the running cost of the chough project for 2016. As a small way of saying thank you Caûvette the chough made an appearance at the Le Braye section of the walk to lend her support. Many thanks to Sarah Nugent for ‘transporting’ Cauvette to Le Braye.

Just a few of the 20, 000 plus participants of the 2016 Collas Crill Island Walk. Photo by Sarah Nugent.

by Liz Corry

Despite a turbulent start to the breeding season the choughs at Durrell had their most productive year to date. We took a slightly different approach to our management of the pairs this year and it seems to have paid off.

We left Issy and Tristan to parent-rear in the display aviary. Out of the three pairs we have, they were the most likely candidates to succeed here despite the aviary being on-show and susceptible to disturbance. We would, of course, step in if the need arose, but in the end all they needed from staff was a constant supply of food.

Issy’s clutch of eggs visible on the nest camera monitor. Photo by Liz Corry.

Issy laid four eggs in total. On 6th May the first two eggs hatched. The chicks looked healthy and the parents were very attentive. The following morning a third chick was visible on the nest camera although it was not very active.

Sadly this last chick did not live very long and by the end of the day the parents had removed the dead chick from the nest.

The fourth egg stayed in the nest for a few days. When it was apparent it was not going to hatch the parents discarded it and focused their efforts on raising their two chicks.

We have been successful in the past with chicks hatching under their parents. However, the few chicks we have had only survived for a few days to a week at the most. Understandably staff were nervous. Visitors to Durrell may have questioned why the aviary was so overgrown when our signage clearly states that choughs require short-cropped grassland. The simple response is “Would you want a large animal with a noisy strimmer spewing grass, thistles, and weeds in front of your baby’s cot?”. We didn’t want to do anything that would distress the parents and could lead to the nest being abandoned.

The on-show display aviary became the breeding aviary for Tristan and Issy this month. Photo by Liz Corry.

However, we do need the birds to be able to forage naturally so the chicks can learn skills for surviving in the wild. The solution was to wait for the chicks to be a couple of weeks old, i.e. past the critical stage, and go in at feeds times with hand shears. Spending five minutes here and there trying to keep on top of things until the family are accepting of a ‘large animal with a  strimmer’.

Tristan and Issy dutifully cared for their two chicks. Photo by Liz Corry

By the 24th, the chicks were almost adult-sized with feathers head-to-tail. They had reached a milestone never achieved at Durrell before. To mark the momentous occasion we gave them leg rings. More out of need than celebration. The best time to add rings and obtain DNA for sexing is when the chicks are three-weeks old. We assigned names to the chicks following the alphabetical system of previous years. These chicks will be S and T. Full names will be given once genders are known and they have been moved up to Sorel which should be in July.

Keeper Kathryn Smith with a three-week-old chough chick ready to collect DNA. Photo by Liz Corry

The story proved to not be as straightforward for the other pairs. We anticipated problems based on previous experience and the fact that we had a new pairing. The plan for these pairs was to allow partial parental incubation then remove eggs to artificially and/or foster incubate the remainder of the time. Once hatched, the chicks would be hand-reared for the first five days before recruiting Gianna to help foster rear until they fledge. Using Gianna as a foster mum helps reduce the chance of the chicks imprinting on the keepers. It also means we get out of having to do the early morning and evening feeds as Gianna can take care of them.

Both pairs laid a clutch of four eggs. This is where it gets complicated. We rescued one egg from Gwinny before her partner had time to do any damage. Once he was relocated she laid another three which we left with her. We only managed to recover two eggs from Mrs Denzel. All three rescued eggs were given to Gianna to carry on incubating.

Keeper Jess Maxwell with the chough eggs in the incubation room. Photo by Liz Corry

Gianna was already incubating three infertile eggs of her own so we simply swapped them over. Since Gianna is very tame she was very accommodating to staff when they needed to weigh and candle the eggs to check on progress. We were not so sure how Gianna would cope with hatching eggs having never experienced it before. To optimise everyone’s chances we relocated the eggs to the incubator at the Bird Department on 18th May a few days prior to hatch date. We gave Gianna dummy eggs to ensure she continued sitting until the time was right to start fostering.

Gwinny incubating her egg. Photo by Liz Corry

Following so far? All this time Gwinny had been incubating three of her own eggs. On the 18th we went to her nest to candle the eggs and found that all three were fertile and on-course for hatching.

Gwinny has looked after hatchlings before, but never succeeded in getting them much beyond that stage. Without a male to help feed her and the chicks we were concerned the odds would be against her.

However, we wanted her to have a chance and gain the experience. We took two of the eggs back to the incubation room and left her with one in the hope that she would cope with having just the one chick to feed. With five eggs in the incubator (three belonging to Gwinny and two belonging to Mrs Denzel) it might give the impression that the next bit was just a breeze. Sit back and wait for the eggs to hatch. Alas no.

To summarise, it feels like an injustice to the work the keepers put in, but to save on digital ink lets just say we had to assist all but one of the eggs. A few had ‘holes’ drilled into the shell to increase air-flow. Two were assisted at hatch because the chick was struggling to do so alone. One egg sadly didn’t make it to hatch because the chick was badly malpositioned and unable to even attempt to break free.

A small hole was ‘drilled’ into a chough egg to aid successful hatching. Photo by Liz Corry.

The first egg to hatch in the incubation room did so on the 21st. Two days later there was a second and the following day, with some help, the final two hatched. In order of hatching the chicks were named U, V, W, and X in hope that all four will succeed and make it to Sorel.

Chough egg hatching at Durrell. Photo by Liz Corry

Assisted hatch at Durrell. Photo by Liz Corry.

A chough chick seconds after hatching at Durrell. Photo by Liz Corry.

The egg left with Gwinny failed to hatch. She remained incubating it for a long time after the due date, but eventually gave up. The egg was taken to the Vet Department for a post-mortem.

Chicks U, V, W and X were hand-fed using tweezers every hour quickly progressing to every two hours as they grew. Feeds began at 6am and finished at 11pm. The chicks were healthy and developing well. When the first chick was five-days-old we relocated it to Gianna‘s nest where she had been patiently waiting. Within three days all four chicks were in the foster nest with Gianna.

Foster mum Gianna helped with feeding the chicks once they reached five days of age. Photo by Liz Corry.

Myself and Bea, the chough placement student, took turns feeding the chicks and Gianna. Five feeds a day from 7.30am until 5.30pm. Gianna carried out the remainder of the feeds. Occasionally trying to feed us too! Luckily Gianna took responsibility for cleaning the nest and disposing of the faecal sacs. In turn we had to clean Gianna before a new species of white-billed chough evolved.

There was a slight worry on the second day of chick V being in the foster nest as it was looking lethargic and had not put on any weight. Chick U had put on weight and was obviously being fed by Gianna. As a precaution V was moved into a heated brooder and regularly hand-fed for the rest of that day. It was then returned to the foster nest before the last feed to spend the night with Gianna and its sibling. The next day V had improved so it stayed in the nest and we target fed that chick whilst Gianna looked after the others.

Regular monitoring of the chicks meant that we could quickly see and react to anything untoward. Fortunately for the rest of the month there were no concerns. With a fledging period of 42 days there is still a long way to go.

The ‘fab four’ chough chicks in their foster nest. Photo by Liz Corry.

By Liz Corry

The choughs in Jersey have had an extremely busy month. There is so much to tell that we have had to break up the report into two parts to save it becoming a Tolstoy-esque report of epic proportions. This first instalment will highlight what has been happening out at Sorel with the free-living group. This will be followed with an update from the choughs in the Wildlife Park whose offspring will hopefully join the flock out on the north coast this summer.

We are very proud to announce that the three nesting pairs in the quarry gained a status promotion this month to ‘breeding’ pairs. We suspected the females had started incubating towards the end of April because they were only leaving their respective nest sites maybe two or three times a day to feed. The rest of the time their partners were providing the food. With a suspected (hatching) due date of Friday 13th we were naturally anxious to see what would happen.

Breeding pair Green and Black. Photo by Liz Corry

Green and his partner Black are a new pairing this year. Green is a proven breeder having reared the wild chick last year with his previous partner Blue. After her mystery disappearance at the start of the year he quickly paired with Black.

Black has managed to keep a secret from the chough team this year. How many chicks will fledge the nest?

The pair  re-used Blue’s old nest. Considering that this was where the wild chick hatched in 2015 we felt fairly confident it would be successful. The exact location of the nest makes it difficult to see inside so we do not know how many eggs she laid.

A week after the due date we went to check on their progress. We attempted to look in the nest using cutting edge modern technology….a video camera gaffer taped to a fishing rod. Disappointingly size does matter. We were an inch short of reaching the centre of the nest.

However, we did hear a chick, possibly two chicks, begging from the nest and the metaphorical bottle of champagne was cracked open.

Our second pairing White and Mauve failed to rear any chicks last year. White is slightly more mature this year and more focused. Regular and prompt visits to the nest ensured that Mauve was well looked after. When we checked their nest we found two healthy looking chicks and two eggs. Sadly those two eggs should have hatched by that stage. That didn’t stop us uncorking metaphorical bottle number 2 in celebration of the two chicks. This now meant we had two confirmed breeding pairs.

White and Mauve’s nest containing two chicks and two unhatched eggs. Photo by Liz Corry

The third pair, Dingle, our hand-reared chick from 2014, and Red were an unknown quantity. Red has never had much luck with the boys and tried desperately to breed last year during her brief five-day fling with Green. As a hand-reared bird no one knew how Dingle would take to parenting. Luckily we had our mole on the inside, Kevin Le Herissier, keeping a cautious watch on the pair. He had no choice really. They nested in his building down in the quarry. Yet again the choughs had chosen a warm, dry, fully operational building to nest in. Rather considerate of them to also choose a site easily accessible.

Chough footprints give the team a clue as to which buildings the birds are using. Photo by Liz Corry

Under guidance, Kevin checked the nest on several occasions so we were able to know that the pair laid a clutch of four eggs. Red started incubating a few days after Black which meant she had a less ominous due date of Sunday 15th May. We left them undisturbed until 20th May when a check confirmed she had two chicks. No sign of the other two eggs. This was amazing news for the team and a proud moment for everyone involved (and cue metaphorical bottle number 3).

Red keeping guard as we checked her nest. Photo by Liz Corry

Two chicks in Red and Dingle’s nest only a few days after hatching. Photo by Liz Corry

Three metaphorical bottles of champagne in one day seemed a little excessive. Especially considering these chicks were only 5-7 days old and had another 35-37 days to get through before fledging. At three-weeks old the nest sites will be revisited to fit leg rings to the chicks and take DNA samples for sexing. By this stage any surviving chicks should make it to fledge. Fingers crossed there will be four to six wild fledglings by the end of June.

In other news…

In the very first week we were concerned over the health of White. He had been sneezing on and off for a couple of weeks. It was difficult to know at first whether this was just due to all the nesting activity in the rock dust at the quarry buildings or an illness. A faecal sample tested positive for Syngamus (gapeworm) so White was caught up in the aviary, medicated, and let straight back out. The sneezing stopped almost immediately and he has not shown any other signs of illness for the rest of the month.

White was treated for Syngamus at the start of May. Photo by Liz Corry

The non-breeding birds

The other non-breeding choughs had a relatively quiet month making the most of having no responsibilities and just playing, bonding, and foraging around Sorel and the quarry. As can be seen in this video:

Or so they would have us believe. The birds started moulting in May which meant the tracking devices starting dropping off one by one. As far as myself and the student were aware, the choughs were always around for the twice-daily feeds and, therefore, always at Sorel. Thanks to a few reports from the public we know that was not the case. There were confirmed sightings of small groups over at Devil’s Hole, Grève de Lecq and Grosnez. We have also had intriguing reports of one or two flying around St Saviour’s parish. Both reports on the same day.

Jersey National Park

There was a strange sighting of a chough at the north end of St Ouen’s Bay hanging out with a puffin at the start of May. There is photographic evidence. Unfortunately for the people involved there is also video evidence.

Caûvette the chough (aka Bea the student) and The National Trust’s puffin made cameos at the launch of the Jersey National Park hosted by Jersey Pearl on 3rd May. The park extends over an area of approximately 30 miles (48km) of Jersey’s coastline including Les Ecréhous, Les Minquiers and Pierres De Lecq or Paternosters.

The real Caûvette and the other choughs at Sorel feature in the launch video using a 360 degree camera.

Dung is fun!

We had another visit in May from the Dung beetle UK Mapping Project team (DUMP) based at Oxford University’s Natural History Museum. Darren Mann, Ceri Watkins, and Sally-Ann Spence returned to Jersey to study the island’s beetle fauna more closely after last year’s surprise find of the rare Aphodius affinis beetle. This time round they enlisted the help of Simon Robson, one of Jersey’s top entomologists, and quite literally delved into the island’s dung.

They were amazed at the wide diversity of dung beetle species present on the tiny island, but alarmed at the lack of abundance. It most likely reflects the quality of habitat and the agricultural practices of modern day Jersey. The addition of sheep at Sorel is the only reason why certain species of beetle are present there. They only feed and, therefore, breakdown and dispose of sheep faeces. Birds On The Edge will feature a report of their visit in the next couple of weeks. Sign up for regular updates to discover why #DungIsFun.

By Liz Corry

Easter may have been early this year, but our chough eggs waited until April was in full swing to make an appearance. The first sign of egg-laying at the Wildlife Park was on 12th April when the nest cameras revealed an egg in Iseult’s nest. Within a week she had finished laying and started incubating.

Iseult’s eggs – view from the nest camera monitor. Photo by Hester Whitehead.

Choughs normally lay around five eggs in captivity with the female starting incubation when the third egg is laid. Issy appeared to be quite restless at first, leaving the nest whenever she was disturbed. As the aviary is on show to the public the decision was made to cordon off the footpath which runs alongside the nest site. This seemed to work well and Issy continued incubating.

The public footpath was blocked to prevent disturbance to the nest whilst Isuelt was incubating. Photo by Liz Corry.

Egg-laying for the other two breeding pairs in the Park was not as straightforward. Both pairs took a long time to progress from a few twigs in their nest-box to a fully lined chough nest. Then it was a matter of waiting for the first egg. It turned out to be a very long wait to the point we had almost given up expecting anything. Seventeen days after Issy laid her first egg Gwinny and Mrs D started laying their own.

Denzel and Mrs D have very little experience in breeding and this is their first time together. Everything appeared ok when Mrs D laid her first egg. Then keepers had a moment of doubt when they checked the nest cameras. “I’m sure there was an egg there before?”, “Is that an egg or a bit of wool?”, “It’s ok its still there”, “Wait, has the egg gone again?” Checking back over the camera footage we realised that what was hoped to be lighting issues and camera trickery was actually Denzel carefully removing the egg from the nest and Mrs D laying her second egg. He did the same thing to the second egg in the evening when staff had gone home.  The remaining eggs were rescued before he had chance to act and given to Gianna to foster incubate.

A slightly different scenario played out next door in Gwinny and Lucifer‘s nest-box. This time it was not just the eggs in danger. Gwinny and Lucifer have had clutches for the past two seasons. There have been issues with each clutch and eggs being tampered with. Staff usually have to rescue to artificially incubate. CeCe being the result of last year’s rescue efforts. We were quite prepared for the same to happen this year. What we were not prepared for was Lucifer‘s reaction to the first egg. As can been seen in the video below he became extremely aggressive to the point where Gwinny was in danger.

Staff reacted quickly and re-housed Lucifer away from the breeding aviaries. There was the slight risk that Gwinny may abandon egg-laying due to the disturbance and not her ‘partner’ not being around. The risk to Gwinny by leaving him in the aviary far outweighed this and our actions were justified as she continued to lay over the next few days and has incubated consistently since then.

Staff rescued the first egg as planned and gave it to Gianna to foster-incubate along with Mrs D‘s two rescued eggs. Gwinny went on to lay three more eggs which were left with her to incubate as she was sitting so well.

Gianna has shown that she has learnt from her experience as a first time mother last year and is even more attentive to her nest this year. As with last year she was given a dummy egg to stimulate egg-laying. This seemed to work and a few days later she produced her own, followed by two more. This is quite interesting as last year her first egg was her only egg. Gianna will be used for foster-incubating and foster-rearing. We are not 100% confident in her ability to look after hatching eggs so any fertile eggs she has will be transferred to an incubator in the Bird Department and subsequent chicks hand-reared for the crucial first few days before returning to Gianna.

Gianna will hopefully help out again by foster rearing this year. Photo by Liz Corry.

Over in Cornwall our partners at Paradise Park appear to be having an easier time with their five breeding pairs. You can watch live footage from their nest cameras by clicking here. Potentially one or more of the chicks you will see on camera will be joining the flock out at Sorel later on this year.Update from Sorel

It was a little harder to determine when the choughs at Sorel started egg-laying. There was a period towards the end of the nest-building stage when the males started displaying to their partners and several mating attempts were observed. Green in particular liked to show off by spreading his wings to full extent and parading around Black. Or any other female that happened to be in sight.

Green showing off the size of his wings to his partner (on the right) on the roof of the aviary. Photo by Liz Corry.

Dingle joined in with collecting wool for his nest with Red. This is really promising behaviour and progress from last season when he partnered up for the first time. He has also been observed taking nesting material from the quarry in the form of lagging around pipes. Very resourceful. A recent roost check showed that the pair have switched from roosting at the aviary to roosting in the quarry. A sure sign they now feel invested in their nest and want to keep a close eye on it.

Dingle collecting nesting material from outside the aviary. Photo by Liz Corry.

We determined that the females had started incubating eggs by observing behaviour before and after the supplementary feeds at the aviary. Black was the first no-show of the three incubating females. As it is only the females who incubate the eggs they try not to leave the nest too often. When they need to leave, they need to know ‘abandoning’ their eggs is worthwhile. The choughs know when to expect food at the aviary because staff stick to set times. Sometimes, however, staff are delayed so instead of taking the risk of flying to the aviary to find there are no food dishes out Black waits for Green to return with the supplementary diet, thereby letting her know staff have put the food dishes in the aviary. After a minute or two discussing the tardiness of the keepers and what’s on today’s menu, the pair will then head over to the aviary, quickly feed, and return on a full stomach to continue incubating the eggs. Mauve and Red followed suit so now all that remains is to continue observing behaviour and count down the days to the expected hatch dates.

We still have the young pairs feeding and preening each other but not yet ready to nest. A new pairing we noticed this month was that of Lee and Caûvette. It will be interesting to see if this relationship continues throughout the year. Caûvette was hand-reared. Any nesting attempt by her will be followed with great enthusiasm not just by the chough team, but by other reintroduction projects around the world.

Lee and Cauvette, a hand-reared female, have paired up. Too young for this year’s breeding season but promising for next year. Photo by Bea Denton.

The other new pairings appear to be going well. Q and his female Noir can be seen below taking part in a spot of mutual preening after lunch.

Q and Noir have bonded over the past couple of months. Photo by Bea Denton.

Q invites Noir to return the favour and preen him. Photo by Bea Denton.

We had one piece of information this month which helped add solid facts to our breeding records, but also brought with it upsetting news. Early morning on the 4^th April and email came in from quarryman Kevin Le Herissier that said “have a bit of good news and a bit of bad news”. I might have then stolen his thunder by suggesting the good news was the discovery of a chough nest.

Dingle and Red’s nest before Red starting laying. Chough nests are protected in the UK and cannot be photographed or approached without a licence. Photo by Liz Corry

What could not have been predicted was the bit that came next. The bad news.

Kevin had been working in the asphalt plant that morning and suddenly heard a group of choughs alarm-calling outside. He noticed several birds looking very distressed, hopping around on the ground, shouting at something. When he got closer he realised that in amongst the cacophony of choughs there was a chough head! No body, no feathers, just a head. We arrived on site shortly after the phone call and after a little detective work we found, at various sites, a piece of wing, intestines, and tail feathers with a radio transmitter attached. From this and her absence at the aviary feeds we knew the deceased was Ormer one of the 2015 chicks from Paradise Park.

Ormer was found dead in the quarry this month potentially predated by great black-backed gulls. Photo by Liz Corry.

Whilst not wanting to sound uncaring, quarry and bird staff breathed a sigh of relief. It was not one of the breeding females and it was not Dusty the wild chick. A loss nonetheless though. I presented the remains to a somewhat perplexed vet team to try to gather as much information as possible from a post mortem examination. Blunt trauma fracture on the skull and descriptions from quarry staff suggest that Ormer and the others had had a run-in with the gulls who also nest in the quarry. Great black-backed gulls are notorious for their aggressiveness and predatory behaviour and were seen nearby (a number of pairs nest in the quarry alongside the more numerous herring gulls) and were considered responsible.

We have observed choughs chase off gulls (normally, or always, herring gulls) simply so they could play on the rocks the gulls were sitting on. Some may use the term ‘bullying’, but we like to think of it as being over-confident. Unfortunately this time around Ormer met with an even more confident species.

Another impressive sunset as staff carry out a roost check. Photo by Bea Denton.