August was a relatively quiet month. Quarantine embargos at the aviary meant that the ten chicks stayed confined to the aviary and the adults gained respite from the hand-reared chicks daily fly-arounds.
Release aviary update.
The six parent-reared chicks have settled in well and are now mixed with Dingle and the girls. There have not been any cases of aggression to worry about. There does still appear to be a subtle separation of groups even when mixed. The behavioural study being carried out by the students shows us that certain birds prefer to hang out with some more than others. A bit like children in a playground, but with less hair pulling.
Glyn testing his Jedi mind skills during a ringing session. Photo by Harriet Clark.
The practicalities of conducting such a study have been complicated by the extra choughs. Primary colours are limited so we are left with grey vs. pale blue leg rings and other subtle variations. Add to that the fact that chough chicks rarely sit still for one minute and it makes the task of distinguishing between 10 birds in 60 seconds feel almost impossible. Nevertheless, the students have been persevering
and the data sets are mounting by the day.
We added radio transmitters to the new chicks and swapped their Paradise Park rings for Channel Islands bird ringing scheme ones. After careful consideration we also gave each chick a name from E to J. Adam had the honour of naming the first chick and whilst it is not directly Jersey related we still think ‘Egg‘ is fitting for a chough.
Flieur, Jèrriais for flower, and Grace were named by Paradise Park staff and we think that their personalities are quite apt for their names.
For chick H it couldn’t really be anything other than Jersey’s patron saint, Helier. Gender aside of course. When it came to chick J we couldn’t ignore gender. We would have loved to have a chough named John, but the femininity is lost. Instead we took the parish of St. John’s Jèrriais name of Jean.
Egg (red), Flieur (grey), Grace (black), Helier (green) and Jean (white) hoovering up mealworms. Photo by Liz Corry.
Icho. Photo by Liz Corry
We were pretty stumped when it came to chick I. Until Glyn made reference to one of Jersey’s Conway’s towers 2 km out to sea. The line being “Wouldn’t it be funny if one of the choughs decided to roost in Icho tower?” “No!” came the reply from the radio-tracking team.
Having completed their quarantine period this month the chicks will begin leaving the aviary at the start of September.
Life outside of the aviary
The six adults flying around Sorel continue to return to the aviary at will. They still eagerly fly to the aviary when we blow the whistle for food, but spend more and more time probing the grazed headland.
Choughs probing the grazed land for insects. Photo by Liz Corry.
Holes in the ground made by chough looking for insects. Photo by Liz Corry.
Much to our delight (stroke alarm at the sheer number) we are now seeing evidence of chough activity and how important it is for them to have grazed areas free of bracken.
Next time you are walking the cliff path at Sorel look down for probing holes in the ground and think about how much insect life must be living under your feet…if the choughs haven’t eaten it all that is.
Pale green flanked by his two females Blue and Mauve. Photo by Liz Corry
The trio of Pale Green and his two females, Mauve and Blue, still spend a lot of time together. He has been seen preening both which suggests he is being a bit of a cad and waiting to see who will be the better choice come breeding season.
At the moment the odds are on Blue, although the geneticists amongst us would prefer a non-sibling pairing.
Whilst some have been showing off their yoga skills Mauve was limping in August. She sustained a mystery injury to her foot which meant she was holding up that leg a lot. It only seemed to give her grief for a few days and a scab that appeared has now dropped off. Fortunately, because the birds return to the aviary and allow staff to get fairly close, we can monitor health issues such as this very easily and make rapid assessments. No intervention was needed this time.
Early morning chough yoga (left). Mauve had to give it a miss with her injured foot (right). Photos by Liz Corry
As we reported last month, the choughs are being more adventurous and living on the edge. The cliff edge! Now there is no stopping them and they have been probing right at the bottom. In heavy downpours they have been seen sheltering under ledges which led us to believe they may no longer be using the quarry buildings to roost in. On arrival for our first roost check we were proven wrong. An hour before sunset five adults flew over the car park to the quarry and didn’t emerge until sunrise.
Roost check at Sorel. Photo by Liz Corry
The sixth, Red, was still feeding in the fields when we approached. When she stopped feeding she realised the other adults had left. She seemed a bit confused and flew to the nearest choughs she could see, those in the aviary. She took a long time to settle, but eventually roosted at the aviary. Oddities aside, the group of six still prefer to sleep in the quarry buildings.
Whilst their roost site selection might not be a new thing, their distance from the aviary is. Or should that be elevation since they are now feeding lower down the cliffs. There are three choughs in the photo below. Trust me.
Choughs foraging near sea level (there are three in this photo!). Photo by Liz Corry
Feeding time at Sorel. Photo by Liz Corry
The sheep, normally present on this bit of headland, were confined to the aviary field in August to allow bracken control treatments to go ahead at Devil’s Hole. Sam and Aaron, the shepherds, have been kept very busy making sure the sheep have enough food and water. We have been kept entertained trying to keep the sheep from busting through the gate to get to the fresh green grass in the aviary. You can read more about the bracken control here.
A VIP visitor from Madagascar
Floriot Randrianarimangason visited the UK and Jersey in August for intensive specialist training in aviculture and captive breeding. Floriot is a member of Durrell’s Madagascar team and runs the pochard captive breeding facility out there. The Madagascar pochard is the world’s rarest duck with only 20-25 known to be living wild.
Floriot Randrianarimangason from Madagascar visited Sorel this month. Photo by Harriet Clark.
Floriot has been to Jersey before; he worked on the ploughshare tortoise project before switching to birds in 2009. He hadn’t visited Sorel before and was keen to learn more about the re-introduction techniques. It is fair to say from the grin on his face he was suitably impressed. Tempting as it was for him, Floriot hasn’t taken any choughs back to Madagascar but he certainly has spread the word about Birds On The Edge and the natural beauty of Jersey.
Mauve returns to the flock (right). Photo by Liz Corry
Panic over, Mauve is back. We don’t know where she went but we know she is back safe and well.
As the birds become more familiar with their environment they will start to explore further afield. It is a bit unusual at this stage in the game and year which is why we asked for help.
Thanks to all of you who contacted us about Mauve. At the start of next year the males will begin looking for territories and some of the females will prospect for nest sites. This is when the fun and games will really begin for the radio-tracking team. We are always pleased to hear from members of the public about their chough sightings. For next year’s breeding season these sightings will not just be heart-warming but invaluable to the project and success of Jersey’s red-billed chough.
Mauve, female red-billed chough, currently missing from the flock on sixteen
We are missing Mauve one of the adults at Sorel. She was last seen yesterday teatime at the aviary with the other fifteen choughs when the keeper called the group back for food. At this morning’s 07:30 check we only had 15 of the 16 choughs at the aviary. They have spent the last week foraging around Sorel and flying high, regularly returning to the aviary. Her absence this morning is therefore unusual.
For those of you living in Jersey please keep an eye (and ear) out for her. She no longer has a radio transmitter attached making the task of finding her trickier for the team. If you think you have spotted her please contact the team on 01534 869059 or email elizabeth.corry@durrell.org.
In the unfortunate event of finding a dead chough please place the body in a clean sealable container or plastic bag and contact the above or Durrell directly as soon as possible. Whilst it would be a blow to the project to lose a bird, we can gain a lot of useful inform from a post mortem.
But lets stay positive for now and assume she has just decided to investigate Jersey’s beautiful coastline.
Alas, whilst the sight of a golden eagle in Jersey’s skies would be amazing we are in fact referring to Paradise Park’s chough chicks hatched this year. Saffron, the golden eagle pictured here, is a long standing member of the ‘Eagles of Paradise’ free flying bird show. I don’t think staff would give her up that easily.
However, they did agree to send over six other chicks to help with the restoration efforts in Jersey.
Many of you who have followed our work closely know that Paradise Park, in Hayle, Cornwall, have provided Durrell with our three breeding pairs of choughs and several juveniles over the last five years. All of the choughs currently flying free at Sorel were captive bred at Paradise Park.
Whilst Durrell have been successful in rearing chicks this year there are only four. To increase our chances of success we need more candidates fo release. Paradise Park’s parent-reared chicks are perfect for the role. The lessons they learnt from their parents will hopefully be shared with Durrell’s chicks whilst the two groups are living in the release aviary up at Sorel.
At the end of July, Harriet Clark and myself travelled over to Paradise Park. We spent a day behind the scenes learning more about their captive-breeding programme including meeting the new chicks.
Sarah-Jayne demonstrating can recycling with the help of a kea. Photo by Liz Corry
We also managed to find time to watch the two free-flying bird shows. The skills the staff demonstrated in the shows have been put to use up at Sorel.
I visited the park in 2011 to learn about animal training for welfare and soft-release purposes. David Woolcock, curator of the Park, has been providing invaluable support to our project ever since.
Parrots and birds of prey are not the only birds participating in their shows. Oggie and Piran are two choughs who love to fly back and forth over the audience whilst staff talk to the public about the perils faced by wild choughs and how conservation efforts are managing to support the population. Jersey gets a mention too!
Oggie and Piran. Photo by Liz Corry
When Oggie and Piran aren’t flying around, they hang out in an aviary where they get to interact with the public. They love being preened (tickled to you and I) and actively walk up to the mesh to meet you. They then seem to go into a trance-like state of pure ecstasy.
If they don’t like it they simply walk away.
The breeding facilities are off show to the public as the choughs can be quite sensitive to disturbance during incubation. These aviaries have nest cameras to monitor the parents behaviour and keep a ‘big brother’ eye on the development of the chicks. Each year they broadcast live to their website so the public can also keep a watchful eye. Of course at this time of year the chicks have already fledged and the families moved out of seclusion into flocking aviaries.
Liz, Harriet, and Ray Hales in the flocking aviary. Photo by Alison Hales
Alison Hales, director of Paradise Park, kindly showed us around armed with a bucket and trowel. Why? Well chough chicks love eating ant larvae and eggs. In order to provide enough to feed all the chicks throughout the breeding season staff placed paving slabs around the park in grassy areas. When the temperatures start to rise in spring and summer the slabs heat up becoming attractive to ants. All staff have to do is flip over the slab and dig out what they need with a trowel before dispensing in the aviaries.
Alison Hales shows Harriet how they provide wild insects to the chough chicks. Photo by Liz Corry
Ant eggs are nutritious and delicious for choughs. Photo by Liz Corry.
It was quite a sight to see so many choughs in one aviary. And a little bit overwhelming to think we would see the same at Sorel in two days time!
Paradise Park’s chough chicks with their parents in the flocking aviary. Photo by Liz Corry
We had planned a visit to track down wild choughs and meet up with the RSPB before heading back to Jersey. You will be able to read about that experience in separate posting. For now, let us explain how we moved six birds 160 miles across land and sea without exerting a single flight feather.
Paradise Park staff caught up and crated the choughs in the morning. David Woolcock then drove them to Perranporth Airport north of Hayle. I say aiport….field is probably more appropriate.
Perranporth Airport. Photo by Liz Corry
There we all waited patiently for the arrival of ‘Durrell Air’. Captain Colin Stevenson and trusty co-pilot Lee Durrell waved excitedly from the window of the Navajo as it taxied off the runway and came to a halt at gate…erm 1 (and only)?
Lee and Colin very kindly donated their time. Anyone who has dealt with animal transportation will apprecite the cost involved and how minimising stress for the animal is paramount. Our alternative of half a days drive to reach a tempremental ferry service facing another 3-9 hour journey would not be in the best interest of the choughs.
Colin and Lee at the helm. Photo by Liz Corry
After a quick cuppa and stretch of the legs we loaded the crates into the cargo hold.
All ready to leave for Jersey. Photo by Alison Hales
Harriet and I found our seats in business class (also doubled up as cargo hold). Then we had to rearrange a few things so the pilots could squeeze through to the cockpits.
Harriet with the precious cargo. Photo by Liz Corry
The birds themselves were relatively settled. Their crates had been secured in place and for the more nervous passenger they were covered over to create a darker, more peacefull environment.
Some just wanted to take in all the sites. Thankfully, fog patches aside, it was a very calm sunny day so the views were amazing and the flight smooth.
On landing we were met by Adam and Max who helped unload the crates into two vehicles. We drove them straight up to Sorel and completed the rest of the journey on foot.
Adam and Max transfer the crates for the next leg of the journey. Photo by Liz Corry
On arrival we were met by the vet and vet student. The birds needed to have a general health examination before being released into the aviary. Blood samples were taken as standard import requirements and cloacal swabs taken for baterial checks. The chicks were uncrated one at a time because of this and then released into section 1A once they had the all clear from the vet.
Vet Alberto examines chicks before their release into the aviary. Photo by Liz Corry
The Durrell hand-reared chicks were very excited by the new arrivals and flew up to meet them. But on seeing the vet and a large syringe they headed back to the other end of the aviary. The two groups of chicks need to be kept separate for the first week whilst we establish if there are any diseases risks, but can then be kept as one group in the aviary to socialise.
As soon as the Paradise Park birds entered the aviary, quarantine restrictions had to be put in place. For a little over four weeks keepers donned latex gloves and blue shoe-protectors everytime they entered the aviary. All waste food and materials were treated as clinical waste (which will explain the sight of Durrell staff hauling a large yellow refuge sac over the cliff tops into their car boot, and driving off).
I am pleased to say quarantine restrictions have now been lifted. The ten chicks (now four months old) are living happily together and are being trained by keepers in preparation for their release.
8 out of 10 choughs. Photo by Liz Corry
Thanks to all the staff at Paradise Park and to Lee and Colin for their time and assistance. Also thanks to Amy Hall, Durrell’s Registrar, for directing me through the piles of paperwork required for imports/exports.
We look forward to an exciting new chapter and the promise of sixteen choughs flying free this year.
By Liz Corry In July’s monthly report we revealed that Durrell’s hand-reared chicks had taken to the skies for the first time. A first for the birds and the project as no chough this young has been released into the wild for a re-introduction project before. Summing up what happened over the twelve days of releases into a couple of paragraphs doesn’t really do it justice. So, we thought we should show you in a bit more detail the antics of Dingle and the girls.
Chicks learning to land at target sites for food. Photo by Liz Corry.
In the days leading up to the first release the chicks were put through their paces. Making sure they knew where to go when they heard the whistle for food; flying lengths of the aviary at least three times a day; squat jumps and press ups morning and night…Ok not the last bit. In fact the physical aspect of their training would only really be achieved once they were out and being tested by the elements. Flight in the polytunnel has its limitations. What the chicks really needed to focus on was learning how the adults go about day to day living. Watching them respond to the keeper, their foraging techniques, reactions to predators and other potential threats. All behaviours key to survival. Again this does have its limitations when you are confined to an aviary. But with the adults regularly visiting the aviary they had plenty of opportunity to pick up the basics.
Adults landing at aviary. Notice the missing tail feathers due to their annual moult. Photo by Liz Corry.
The problem we faced was that the chicks became so obsessed with the adults that when the adults were not at the aviary the chicks would just take naps in the roost boxes and not want to train with us. To add to our exasperation we wanted to release the chicks when the adults were not around, i.e. when they were in the quarry. We wanted the chicks to learn how to go in and out of the aviary at their own pace. More importantly, we didn’t want the adults around when it was time to shut the chicks in.
Chicks observing the adults eating mealworms at a training session. Photo by Liz Corry.
They would either create a distraction or end up getting locked in with the chicks. So on the day of the first release we waited for the adults to head to the quarry, opened the hatches, and waited. And waited… The chicks had disappeared into their favourite roost box just inches from the hatches. A change of tactic was clearly needed after twenty minutes of no activity. We called the chicks down for a meagre amount of insects at the other end of the aviary. The idea being they would emerge, become active and then see the hatches open and start exploring. This worked and it didn’t take too long for one of them to go outside. With baited breath we clung to every heartbeat wondering what would happen. How high would they fly? How far would they go? Who would they meet? We didn’t account for Dingle hopping down to the floor and taking a bath in the adult’s water tray! Obviously very content.
The chicks are joined by some of the adults at the aviary. Photo by Liz Corry.
Inevitably the adults returned to the aviary before we were ready to call the chicks back inside. The youngsters showed a lot more excitement than the adults whose single focus was food. That motivation kept everyone close to the aviary. The adults perched on the aviary looking on as the chicks would occasionally launch themselves from the netting and whizz around the aviary. When it came time to close the hatches the adults were inside on the whistle before the chicks. Likewise as we approached to close the hatches the adults were the first out. Knowing full well closure meant no evening playtime in the quarry, they were not willing to stay. The chicks on the other hand continued eating oblivious to what was occurring. The adults stayed nearby so when the whistle was blown to reward the group with their favourite treat they flew in and landed back on the aviary. Their calm obedience was a testament to how well they have adapted to the wild. It was definitely one of the most rewarding days for everyone on the chough team. The next day was pretty much the same. The only exception being the arrival of the peregrine family minutes after the hatches were opened. They had been a common feature of Sorel in the preceding days. The young peregrines saw the adult choughs as target practice. They would swoop down and chase the birds. Unlike the neighbouring crows and magpies, the choughs would always stick together flying in formation. I think this helped as no chough could be picked out as an easy target. The choughs could also play the ace card of returning to the aviary and fading into the background of the black shelves and netting. The chicks first ‘encounter’ in the wild with the peregrines involved them staring up from the external shelves observing the commotion above. After opening the hatches the chicks were still inside when I heard distant chough calls from behind the aviary. On the horizon the image of five dots very quickly formed into five choughs flying with determination towards the aviary. Scanning the skies for the sixth chough revealed two interweaving shapes approaching from inland, one a chough, the second definitely a peregrine. Through grit and determination (and a bit of cockiness when she retaliated) she made it back to the aviary unscathed along with the other five who had landed sometime before. The chicks by this point had already flown back inside into the farthest depths of the aviary. We locked them in half of the tunnel and allowed the adults in the other half for respite until the peregrine left. On another occasion two juvenile peregrines chased the group flying no more than 20ft above my head whilst sat by the open hatches. That event, as you can imagine was a blur at the time. And after! Even the frantic camera clicking pointing in hope at the sky didn’t do it justice.
One of several peregrine attacks at the release aviary. The choughs took shelter in the aviary. Photo by Liz Corry.
It wasn’t always that easy to get the chicks back inside the aviary. Bean’s behaviour on the fifth night of releasing was a prime example. To be fair to her, the afternoon had been quite challenging. Minutes after the hatches had opened the choughs were being harassed by a peregrine so the chicks were locked back in until it left (I realise at some point there will be losses due to predation, but not at the aviary, not on my watch!). Then when they were allowed out again the wind picked up. For a species that nests in sea caves and lives near the cliffs a bit of wind should not be a problem. However, for a soft release, a cross wind or worse, one that propels them towards a small opening in a wooden frame, can be challenging if they haven’t mastered all the tricks of flight. It wasn’t just Bean having difficulties that day.
Bean sat on the netting trying to figure out how to get back inside. Photo by Liz Corry
Then again my sympathies diminished after one of many failed attempts to coax her back inside. I had walked them down from the sheds to the hatches by talking nicely and waving insects in their faces. Hand-reared chicks are very compliant that way. When they saw the hatches they started to hop inside one by one heading for the food dishes. All except Bean who stumbled at the last hurdle. All she had to do was cross from one shelf to the other a few inches away. Max had even put up a perch that morning to bridge the gap. She stared at me, stared at the gap, then flew back to the other end of the aviary and sat above the other three chicks feeding below.
Staff wait patiently for Bean to make her way back inside the aviary. Photo by Liz Corry.
In this situation the protocol is to shut in the birds you can, lock them into one section, and hope they will act as a lure to encourage the straggler(s) in. There comes a point when the chough left outside no longer cares about food and just worries about where it will roost for the night. That’s when we have to set aside the training methods and just sit guarding them patiently until they find their way back. Bean herself seemed relatively calm. She spent time preening and sitting next to the other chicks (well just above them to be specific). She did explore the roof and fly back and forth trying to find a way in. She even sat in the external roost boxes once or twice. Never once did she go to the hatches. As the sun sank below the cliff tops she was visibly more agitated and starting darting away from the aviary calling to the others. She finally settled, not in the external roost boxes, but out on the netting just next to the roost box the chicks were sleeping in. We left her just before 10pm and I returned at 5.30am before the sun was up, to find her in exactly the same spot.
Bean warming up after a night out alone. Photo by Liz Corry
Much to my relief she was alive although very sleepy. To be fair the other three had not really woken up either. I was worried that the night out and stress of yesterday had taken its toll. Luckily all she needed was a soak in the sun. As it started to rise above the hill she moved to an external roost box and sat preening in the full sun. Soon she had made her own way back inside and by 6.38 am she was reunited with the others. The soft release continued for a further four nights. The chicks spent their time outside foraging with the adults in amongst the sheep, exploring the cliff tops and playing on the air currents. They have certainly explored further than the adults ever did at this stage in the soft release process. It is a really positive sign for things yet to come.
Chicks and adults flying free. Photo by Liz Corry
We had to put the releases on hold whilst we went to collect six new birds from Paradise Park. After which point all the aviary birds would be in quarantine lockdown for thirty days minimum. You can imagine the tension then on the last night before our departure when we let the chicks out at 3pm. Stress levels, already above average, peaked when the adults decided it was time to head back to the quarry and the chicks followed. In flight there was an obvious split between the two groups as the chicks lagged behind. From our view point we think they made it as far as the car park. From their position they would have been able to see the quarry. Whether it was the moving cars, the site of the quarry, or general lethargy the chicks changed their minds turned around and flew straight back to the aviary. I don’t think any of us could have predicted how well this round of soft releases has gone. Let’s hope the next phase with the parent-reared chicks will be just as successful.
July was yet another action packed month in which the goal of re-establishing a sustainable wild chough population in Jersey moved another step closer to being a reality.
Winners announced for Insurance Corporation Conservation Awards Jersey 2014
The Durrell chough chicks entered their first competition this month. Not a beauty pageant, we are still working on their talent skills, but a conservation award to help fund their post-release monitoring.
Insurance Corporation of the Channel Islands holds an annual competition to recognize the efforts of local conservation projects and award prize money to fund continued work.
The chicks faced stiff competition from several amazing projects representing a range of local fauna and flora from bioluminescent marine worms to grass snakes and reed beds. Insurance Corporation Jersey manager and chair of the judging panel, Natasha Lucock, says that the quality of entries this year was higher than ever.
“It’s great to see so many people taking an interest in Jersey’s green spaces and making such huge efforts to preserve the life that can be found there.”
I am pleased to say that the chicks won the Peter Walpole’s People’s Choice Award, as voted for by fans of the Insurance Corporation Facebook page.
Winners of the Insurance Corporation Conservation Awards 2014. Photo (c) Insurance Corporation
“Over 450 people viewed and voted for their favorite videos of the various projects on our Facebook page and we were delighted to present Durrell with £500 as the people’s choice winners named in honour of our chairman and conservation awards founder, Peter Walpole,” added Natasha.
The money will buy radio transmitters for the chicks to monitor their movements post-release.
We should be able to locate any chick that roams out of sight. Combining their daily movements with geographical information databases we can say which habitat and local areas they prefer to forage in and roost and then feed this into future land management plans.
The Inspiration Award of £500 went to Robert Ward for his efforts in studying and conserving the local grass snake and slow-worm population. Robert is on Jersey conducting research for his PhD with DICE (Durrell Institute of Conservation and Ecology), which will be running until October 2016, seeks to determine the population of both species along with investigating their movements and habitat.
Chickay, Bean, Caûvette, and Dingle were measured up and kitted out in preparation for their first flight outside of the aviary. The chicks had leg rings and tail mounted radio-transmitters fitted by the keepers. They were happily feeding and playing afterwards and don’t seem hampered in any way by the extra equipment.
Measurements of wing and tarsus lengths were recorded to add to an existing European database. Whilst not 100% accurate these measurements can be used to determine sex when DNA analysis is not available.
Their behavioural training has progressed well. They respond to the whistle and fly down to target boards to feed. At first Caûvette seemed to be apprehensive about flying through open hatches. The other three would glide through, but Caûvette seems to bail at the last-minute and fly up to the shelf above. For whatever reason, confidence or acquired skill, she has improved. All this made it look promising for the chicks’ first release.
Maiden voyage of Durrell’s hand-reared chicks
It was imperative to get the chicks flying out with the adults as soon as possible this month. At two months of age they are eager to learn and the adults are the perfect teachers. There was an added pressure of knowing that an import of new choughs on the 24th July would mean all birds inside the aviary would go on a thirty-day quarantine lock-down. If a release was delayed until September the chicks would be older and maybe more complacent.
Durrell chicks stretching their wings for the first time outside of the aviary. Photo by Liz Corry
On the 8th July the Durrell chicks took their first venture into the wilds of Sorel. The hatches were opened late afternoon and the chicks were given 30 minutes of free time. It proved more successful than anyone could imagine. The chicks ventured outside although not very far. Sticking closely to the roof of the aviary they took several small circular flights. When the adults appeared from the direction of Sorel point the chicks became very animated, but still stayed close to the aviary. Mainly because the adults were doing the same thing.
Flying with the adults above the aviary. Photo by Liz Corry
When it was time to call them back the adults were still at or even in the aviary. Instead of trying to scare them out we decided to use them as lures and the chicks would hopefully learn by example. The adults heard the whistle, spotted the keeper, and flew to the target boards inside the aviary for food. The chicks followed, although not instantly.
Knowing how the adults now react to hatches being closed by keepers, there was a good chance they would fly out or worse some would get shut in the aviary. The chicks being naive to such a thing might stay eating or fly out reacting to the panic of the adults.
What actually happened was that the adults all flew out as soon as the keeper approached from the front. The chicks remained eating whilst watching the adults leave. Hatches were locked and the chicks stayed safely inside for the night. The adults were unfazed by the whole affair as they returned straight away on the whistle for bonus insects.
Max observing the four chicks as they fly around Mourier Valley. Photo by Liz Corry
Ten releases happened in total over two weeks in July. Free time ranged from 30 minutes to 5 hours and there was only one night when one chick stayed out on the roof all night. They avoided several aerial attacks from juvenile peregrines learning their own trade. They have now learnt to fly inside the aviary under shelter when the peregrines are around. The adult choughs were present each time and no doubt the chicks learnt what to do from the adults reactions. The adults have not been injured by the peregrine encounters despite physical contact and always seek the aviary for shelter. Fortunately for them these are young peregrine practicing to hunt. Things could be dramatically different when they no longer need to practice.
Peregrines in training at Sorel. Photo by Liz Corry
If the challenge of predator encounters was not enough the Durrell chicks’ ‘playtime’ outside has led to an increase in syngamus and coccidia levels in their faeces. The symptoms are repetitive sneezing and wheezing. This is not unexpected as these naturally occur in the wild and the physical demands of first time wild flight will weaken birds making them more susceptible. All four chicks were immediately put on a course of baycox and ivomec due for completion the first week in August. Within days the chicks appeared healthier, but they still need to complete the course.
Changing of the guard
Ex-student Pierre Rauscher. Photo by Liz Corry
We sadly bid farewell to one of our students at the start of the month. Pierre’s three month placement on the project had come to an end.
Pierre’s first day was when we first started releasing the adults locked in overwinter. He saw the Durrell pairs lay eggs and was able to experience the highs and lows of chick rearing.
It only seemed fitting then for his last day to be the day we gave the chicks their first taste of life in the wild. Pierre enjoyed his time with the choughs and the Bird department, but has said he will not miss the wind up at Sorel! Having been blown backwards on the cliff path whilst tracking birds in May I can understand why he said that.
Harriet Clark with new student Max Benatar. Photo by Liz Corry
The very next day we welcomed Max Benatar to the team. Max is a student at the University of Zeppelin, Germany. Thrown in at the deep end, Max was given a crash course in radio-tracking before manning his post on the cliffs for the second day of the chick release. Fortunately for him the birds behaved like a dream.
Our other student, Adam, has shown him the ropes when it comes to the behavioral observations and both have received training in basic husbandry skills at the aviary.
Now you see them now you don’t
The sheep at Sorel have been have been updating their summer wardrobe. Aaron and Sam have been busy shearing the flock which is very laborious as it involved herding sheep from both sides of the valley and the cliff faces.
The sheep at Sorel with their summer coats. Photo by Liz Corry
They have been using the aviary field to hold and process who they can. Inevitably the odd one will evade capture so it took several days. When the sheep are in field the gates have to be locked to prevent accidental escapes. This might be confusing to the regular visitor, but hopefully they understand the need for the restriction.
The flock is now back out roaming between Sorel and Devil’s hole. Looking slightly darker than before (their top coat is beige, but underneath its brown). Of course with strong summer sun we are having the sheep are seeking refuge. So don’t be surprised if you hear bracken or a gorse bush bleating at you and not a sheep in sight!
Sorel aviary maintenance
Yet more DIY work was needed at the aviary this month. The joins in the plywood roofing panels which had been filled with all-weather sealant in the spring have once again become exposed. The intense heat beating down on the wood really tested the brand name’s claim and unfortunately it failed. So a new approach was taken and now the roof should now stop the chough’s food from getting wet….if Jersey ever escapes the drought.
The release wires continue to be replaced with tougher galvanized steel wire. We have been waiting on a delivery to the island since we bought out a certain chain store’s stock last month. A few more ‘training perches’ have been added to the outside of the aviary to help the chicks when they exit the aviary. It provides them with a few extra options to sit and catch their breath. Choughs don’t perch in trees and ground level exposes a bird to potential threats from mammal predators or mischievous dogs off leads.
We are now looking at ways to improve the release hatch design and efficiency of opening and locking. Although fitting anything at this stage might be hampered by having ten birds locked in the aviary.
Wildlife park chough update
Gianna finding insects hidden in an enrichment log. Photo by Liz Corry
Funding has been found to replace the old netting on the display aviary and modify the buidling. Hopefully this will make the aviary more appealing for both the choughs and the visitors. In preparation for the work the two females housed in the aviary, Gianna and Issy, have been moved off-show.
Once the work is completed the breeding pairs and the two single females will be flocked together in the display aviary as they would do in the wild.
Sadly there have been no further sightings of Arthur. David Woolcock, the red-billed chough studbook holder, is looking at options for Durrell to acquire a new breeding male and return our holdings to three breeding pairs.
Paradise Park’s chicks boost Jersey’s chough population by 50%
With the exception of our Italian female, all our choughs are from, or descendants of, Paradise Park’s captive population. Genetically these are North Welsh birds not Cornish just to confuse people. This year Paradise Park successfully parent-reared eight choughs and there was even a case of one female becoming a foster mum.
Chough chicks and parents in their flocking aviary at Paradise Park, Cornwall. Photo by Liz Corry
Ali and Ray explaining their flocking aviary setup. Photo by Liz Corry
Paradise Park very generously agreed to send six of the eight chicks to Jersey to take part in the release program. Having been parent-reared the hope is that they will pass on the skills they learned from their parents to the Durrell chicks.
In return the Durrell chicks will guide them through the behavioural training, hopefully tell them the keepers are trustworthy people, and generally ease the transition phase from captive to released birds.
The chicks were caught up and put into crates by Paradise Park staff Olly Frost and David Woolcock. They were then driven to Perranporth airport to meet Lee Durrell and Colin Stevenson. Lee had very kindly offered to fly them back to Jersey on her plane with Colin piloting. A potential eight hour van journey via a ferry was swiftly cut down to 55 minutes with the choughs arriving in Jersey by lunchtime on the 24th July.
Flying into land at Jersey. Photo by Liz Corry
They were driven in convoy up to the aviary at Sorel by Colin and students Adam and Max. There they were met by Durrell’s vet team to examine them and take blood samples for health screening. The Durrell chicks were very excited to hear the first ‘foreign’ chough call. However the presence of six people, one holding a syringe, quickly dampened their excitement. The free-flying adults outside did not appear bothered by the new arrivals they simply wanted their afternoon feed before returning to the fields.
The new arrivals had to spend a week isolated in section 1A of the aviary whilst awaiting the results of the blood tests. If clear they can be mixed with the other four in section 2. All choughs inside the aviary are under quarantine conditions as soon as the first Paradise Park chick left its crate. As such they must remain locked inside until given the all clear.
This seemed to prove frustrating to the Durrell chicks at first. Having recently been given the opportunity to fly free for several hours they seemed annoyed and confused as to why they were being separated from the adults. The new arrivals also took a keen interest in the adults. For the first few days the new chicks would hide in the shelter boxes but leap out whenever they heard the calls of the adults arriving at the aviary.
View from inside keeper porch. Photo by Liz Corry
Interestingly there was not much interaction between the two groups of chicks. This can only be taken as a good thing as the two groups feed next to each other without any fighting or bullying.
The two groups are due to mix next month. Max and Adam will continue with behavioral observations to assess how well the groups integrate and results will be published in next month’s report.
A wild Cornish chough. Photo by Liz Corry
Liz Corry and Harriet Clark traveled to Cornwall three days before the import. A day was spent behind the scenes at Paradise Park kindly shown around by Alison and Ray Hales.Followed by a 36 hour chough hunt to see wild choughs and learn how the RSPB are working to protect this species and their habitat.
Claire Mucklow, RSPB Cornwall chough project manager, and Nicola Shanks, chough project officer, generously gave up their morning to chauffer Durrell staff across fields and cliff tops. Fourteen choughs were counted at one roost site, accounting for almost half of the Cornish population.
A report on the trip to Cornwall including a guided tour by the RSPB of wild Cornish chough habitat will feature on this website very soon! For more news about the wild choughs in Cornwall click here.
It wasn’t long before the chicks started to launch themselves at the keeper begging for food when the nest-box door was opened. The first to leave the nest box was Chickay closely followed by Bean. Eagerly following the puppet and blindly knocking over anything in their path to get to the food: in most cases this meant pots of insects carefully weighed out for each chick.
Being the smallest, Caûvette would often get pushed to the bottom of the begging pile, but once out of the nest she would stand her ground. She then developed a habit of eating a few mouthfuls then getting distracted and exploring the nooks and crannies surrounding the nest area. We took this inquisitive nature to be a good sign for her development. Watching her grow up, we might now be inclined to attribute it to her ‘ditsy’ nature instead. It will be interesting to see how this translates when she is released.
Dingle was the last to leave the nest. Photo by Liz Corry
The youngest of the chicks, Dingle, was the last to leave the nest box. This was several days after Caûvette had left. Although it should be noted that after every feed and brief exploratory session the chicks would jump back into the box and have a ‘nap’ until the next feed. So he was never really left alone. When he did leave he quickly turned from being apprehensive to boisterous and more agile at moving around the enclosure than the other three.
Durrell’s Maintenance volunteers built a wooden ‘staircase’ complete with handrail so Harriet and Liz could safely access the nest-box when feeding chicks. The idea behind this design rather than just using a step-ladder was to avoid disturbance setting up a ladder each time, especially when the chicks were mobile. Plus, when they started learning to jump and fly around, the wide wooden steps became great additional perching points. In the last two weeks of June the chicks were so mobile that they were given access to the second shed section of the aviary. This meant the adults had fewer roosting areas to choose from. Soon the chicks had access to the entire aviary, whistle training began, and the adults had to be locked out.
Wooden staircase built so keepers could safely access nest. Photo by Liz Corry
Training
Whilst secure in the aviary, the youngsters have learnt some of the basic flying and landing skills. At the start this meant landing on the closest solid object they could see…the keeper’s head! Whilst endearing, this had to be discouraged as it is not a behaviour we wish them to have around members of the public. This led to a lot of ducking and diving and a new game of keeper dodge-ball was created. The chicks’ behaviour changed within a few days and feeding times became a calmer affair (although it is all relative).
The chicks were gradually weaned off hand-feeds with insects just presented to them in dishes and the mouse diet swapped for the adult egg diet. Once this was established keepers’ started blowing the whistle as the food was presented at various target sites within the aviary. Within 24 hours the chicks had learnt to associate the whistle with food.
The chicks grew up quickly learning how to feed for themselves and weigh-in! Photos by Liz Corry
Once they are reasonably competent they will be given the opportunity to leave the aviary if they wish. The birds need to be trained in the same way as the adults, to respond to a call for food so we have some control over them. Being hand-reared this should be easy. Within a day they learnt that the whistle meant food was around.
Flying back and forth between target sites was a little trickier to pick up. Only because, whenever the adults appeared outside the aviary the chicks wanted to be with them. If the adults went to the ground feeding, the chicks would go to the ground. If the adults rested on the poly-tunnel frame the chicks would perch on the highest shelf possible. Being whistle-trained themselves, the adults reappear whenever they hear the chicks being trained so you can imagine how often the chicks’ training is interrupted. We are now working on training the chicks to a different cue whilst in the aviary and then switching back once they are released.
Socialisation
Before being released it is important to work out how the other choughs react to new arrivals. If they are accepted by the already released choughs then it will be easier for the chicks to learn from the adults. However, some of the older birds may be hostile and territorial and management issues will arise.
For the first few days of the chicks being in the aviary the group was under constant surveillance. A camera was on the nest area for night time monitoring and keepers or students were taking shifts during the day keeping watch. A study was implemented to record behavioural observations looking at adult interactions with chicks. This will continue until the chicks are released providing valuable information for modelling future release management.
As previously mentioned, the adults took a great interest but none of it was aggressive. If there was any it was more likely directed at the keepers in jealousy of the chicks being fed and not them. The adult females would take an interest in the chicks. On one occasion a female was seen carrying insects in her bill towards the chicks. The mesh between them prevented any feeding if that was indeed her intention.
Once the chicks had access beyond the shed sections they would fly to be as close as possible to the adults when they returned to the aviary. In the absence of the adults they tended to go into the roost-box recently built by Adam and Harriet. The chicks knew without anyone showing them that they had to probe for insects. Whether this was between the timber frame looking for woodlice or in the soil, it was obviously innate behaviour. The presence of the adults at feed times has helped them develop this skill. They watched them and copied their behaviours.
One behaviour they knew already was bathing. As soon as a water-tray was added Caûvette jumped (or stumbled, take your pick) into it and started flicking water in the face of the keeper. Not intentionally. It did take several attempts before she mastered the art of balancing and bathing, but don’t we all!
Caûvette taking a bath. Photo by Liz Corry
The free-flying group
There were a lot of firsts for the adults at Sorel as well as for the chicks. The adults adapted very well to the new residents. When they were locked out of the aviary for the first time they took up roosting in the quarry. This has continued and seems to be a good compromise. They spend their days away from the quarry flying between field and aviary finding food. Occasionally if it got too hot they would return to the quarry buildings presumably because the buildings were shaded and cooler. They also preferred that option during this year’s Round-the-Island-Walk when 200 plus sheep had congregated on the same patch of headland. Who can blame them?
Whilst they choose to roost communally and on the whole feed together there are definite divides within the group. The young male, White, and female Black will often ditch the group to make trips back to the aviary. Red who is no longer partnered up can be seen with them or by herself entirely. It appears that the romance between Green and Mauve has faded. Now the breeding season for them is finished he, Green, has been seen with Blue who has been preening him in front of Mauve. These three are often seen perching or standing together during the day.
The adults started to use the cliff face adjacent to the aviary for the first time. Again this might be because it was slightly cooler than sitting exposed on top of an aviary. Following their movements became slightly harder once all the adults had moulted their radio transmitters. Three transmitters were recovered in the aviary; the other three could not be located. We suspect at least one was lost in the quarry. The batteries by this stage had become very weak making it difficult to pick up a signal at distance beyond 50metres. On one occasion, with no visual and only a faint signal, we had to assume the chough was fine and roosting in the quarry buildings from the echo of what sounded like a chough in a tin can!
We will not replace the transmitters on all of these adult birds. They have established themselves reasonably well in the wild and continue to use the aviary on a daily basis so we can monitor their health close up. As the 2015 breeding season approaches we may look into reattaching to the male, Green, to follow his movement as he, hopefully, attempts to set up a breeding territory.
Until then the adults will be kept busy teaching the chicks all they know about life at Sorel. Of course we all know the best lessons are the practical ones, which for our chough chicks means venturing beyond the safety of the aviary.
Health screening and diet analysis
Faecal samples continue to be collected to monitor parasite loads in the chicks and adults pre- and post-release. We are continuing to collect faecal samples for diet analysis although we have not yet braved sifting through them trying to ID insect remains. Both these projects will continue for the lifetime of the project. Any results will be published on the Birds On The Edge website.
We announced the hatching of four chough chicks in April and May. DNA results, from blood samples taken in May, came back this month showing that we have one male and three females. We had guessed as much based on body weights when they were a few weeks old. Males tend to be heavier and of a slightly larger build.
In addition to this we built on their individual identities by giving them names. We intend to name any chicks reared for release on an alphabetical basis and with relevant names. They might not seem obvious choices to a non-Jersey resident but we think they are fitting names.
This month’s report is being split up over the week so we can introduce properly our four new, Jersey-bred, choughs.
June was an amazing month of firsts for the project and the choughs: it marked a new chapter in the lives of the free-living choughs as well as for the chicks. In turn, the project moved forward into exciting new territory….and I don’t just mean Alderney!
Living Islands: Live
For the first two weeks in June, Durrell participated in Living Islands: Live. This is an exciting cross curricular education project run by Alderney Wildlife Trust in association with South East Grid for Learning Associates. It offers schools the opportunity to bring the fascinating life of the puffin and other seabirds live into their classrooms. One of the many ways in which this is done is through interacting with the live webcams set up on the island of Burhou. Living Islands: Live links directly to the Key stage 1 & 2 curriculum, and is an effective way of teaching science and literacy skills, and promoting pupil creativity and confidence.
Durrell was invited to take over for two weeks to teach children about the chough reintroduction project and how it relates to the broader role of Birds On The Edge. Daily blogs, updates from the field and weekly homework questions kept the children engaged. At the end of each week live webchats were held for participating schools to fire off gruelling questions to team members. Throughout, and continuing to this day, participants can also leave questions and comments on the message forum.
Feedback from the schools was encouraging and supportive. The children loved to see the chough chicks being hand-reared and are super keen on borrowing Arthur the chough outfit. Although, at the end of the day, I have a sneaky suspicion that the puffin is still their favourite.
We have a confession though. We may have told a few white lies to young and gullible children. Well, not lies, more like omissions. During those two weeks something very exciting was happening on the project. Due to the sensitive nature surrounding it and to ensure that it worked to the best of our abilities, only project partners were informed of our plan. Known as “Operation: Moving day” our plan was simple yet fraught with a hundred and one ways to go wrong.
Operation: Moving day
The soft-release methodology has always been based around the need to release juveniles not adults. Young are quick to learn and eager to respond to the keeper. For one reason or another we have not been able to put this into practice. The birds available to us have ranged from 1 to 4 years of age at time of release. With a chough’s sexually maturity hitting around 3 to 4 years of age it means we have in effect been working with teenagers. Hormones sometimes raging, reluctance to do what they are asked, staying out all hours, but still wanting their ‘parents’ to provide food and lodgings. Sound at all familiar?
The six flying around Sorel prove it can work without very young birds. However, it hasn’t been easy and there have been expected losses. Now with the four hand-reared chicks we finally have the opportunity to do what we set out to do.
Our plan was to follow the “hacking” approach used successfully with birds of prey, but with a bit of tweaking to suit our circumstances. The chicks needed to be taken up to the release site before fledging and placed in a nest-box within the release cage.
The advantage to getting the birds up to Sorel and released as young as possible is that the birds learn all of the appropriate social and survival skills at the times they normally would during their early development in the wild. The four birds might have some behavioural problems associated with the hand-rearing. However, being raised as a group instead of individuals, will make some of these obsolete and others should correct themselves during the post-fledging socialisation with the released birds.
Chicks moved from the brooder to the rearing cages once they could survive at room temperatures. Photo by Liz Corry
There was a considerable amount of preparation needed before the chicks could be moved. At Durrell the chicks needed to be acclimatised to outside weather conditions. Room temperature was gradually reduced and skylights left open during the day. We couldn’t avoid the fact the chicks were housed in a brick building and that conditions would be very different to those of a netted aviary on the cliffs. So, adjustments were made to the aviary at Sorel to make it a bit more windproof and insulated around the nest-box. The chicks would be shut in to one of the roofed shed sections to aid this.
The nest-box was placed high in a corner with ledges and perches surrounding it to allow the birds to easily leave and return to the box. Choughs tend to explore their rocky surroundings before taking their first true flight. A chick might leave the nest and start ‘bouldering’ at say age 37 days, but not actually take flight until day 42.
A mesh door was attached to the next box so the chicks could be shut securely in at night. Photo by Liz Corry
We added a mesh door to the next box as a security measure. Until the chicks started to explore we wanted to be able to shut them in overnight preventing any unnecessary tumbles in our absence. More importantly it was to stop any rodents getting to them. There had been an increase in rodent activity in May. Holes were appearing in the netting and with hatches left open for the adults there was an open invite to go inside the aviary.
Adam and Pierre helped excavate ground and lay down half-inch weld-mesh securing it to existing mesh on the sides on the aviary shed. Any gaps in the ceiling or wall mesh were secured until the entire section was rodent-proof. Soil and turf had to be replaced so the chicks had something to probe on the ground without damaging their bills on the mesh.
We also had to consider the adults flying free as they would need to be locked out of one section to start with, and eventually from the entire aviary. This would mean a reduction in potential roost/shelter sites so we added two new roost-boxes to the polytunnel. We were not confident they would use them simply because they roost together and the boxes would only accommodate three or four at a time. They always have the quarry as their friendly alternative.
Chicks were transported to the aviary by car and on foot on the 2nd June. Photo by Dan Lay
On 2nd June, the chicks were moved from the rearing rooms at the Durrell Bird Department to the release aviary at Sorel. We tried to do this as covertly as possible to avoid attracting attention. It was very difficult to do this with four chicks loudly chirping away continuously from the car park to the aviary. Once inside and settled into their nest box they were deafening with their begging. It can only be a good thing as it meant they weren’t fazed by the move.
Hand-feeding continued in exactly the same way as before with feeds starting at 7am and finishing around 7pm. The first feed up at Sorel was entertaining for all as the chicks begging attracted the attention of the adults from the cliff path. The noise inside and out of the aviary was ear-splitting as the chicks begged loudly and the adults wanted to know who the new arrivals were. The adults walked along the roof to get a good look into the ‘fledging cage’, but with the chicks in the nest-box they were not able to see each other. By the second feed the noise from the adults had died down and only a few of the single females wanted to peer in.
From then on the adults would use the chicks begging call as a cue to fly to the aviary in full knowledge a keeper would be there with food. The adults continued to roost in the aviary whilst the chicks were locked in the one section.
In the next report we will introduce you properly to the newcomers.
As reported last month, Durrell has been artificially incubating chough eggs this year. On 30th April our first egg hatched. Closely followed by a second then three more within a week. These eggs were from the first clutches of two different pairs.
Recently hatched chicks are housed in a heated brooder. Photo by Liz Corry
It is always a worrying time waiting for an egg to hatch. It can take over 24 hours for a chough to hatch out of its shell and ours certainly were not in a rush. If a chick is strong and healthy it has no problems hatching. Occasionally, however, a chick is too weak and struggles. We encountered this in two of our eggs, the chicks began external pipping (chipping away at the egg shell) but were sadly too weak to break out and died in the shell.
The five chicks which did successfully hatch were still not in the clear. As mentioned in last month’s report one of these chicks had complications with a protruding yolk-sac and died within a few days. The other four did much better and grew bigger each day. Quite an achievement considering staff had never hand-reared a chough before and rearing from the egg stage is always the hardest.
Chicks kept in a ceramic dish lined with paper towel to create nesting environment. Photo by Liz Corry
The hand-rearing protocol used was based on our previous experience with rearing passerines. We also looked to Paradise Park for information, as they have tried artificial incubating and hand-rearing choughs in the past, as well as to other global institutions who have corvid experience.
We fed the chicks a diet of finely chopped mice and papaya with insects added from day 3. To start with they were fed every hour from 6am until 11pm. As they get older their energy demands change and they only need feeding every 90 minutes or two hours. We also cut back on the duration of feeds so that by the time they were a few weeks old they were fed from 7am until 7pm.
Chough chicks at around ten days old. Photo by Liz Corry
When we feed them we play back recordings of wild chicks begging, the noise the female makes at the nest when arriving with food and, in between feeds, we play adult flight calls. This helps the chicks to associate with chough voices and not the human ones around them. To aid this we also minimised the amount of human contact time and stopped taking them home in the evenings. At Durrell we usually take the hand-reared birds home with us to avoid making several trips back to the office at night and at 6am in the morning. This stops when the chicks are about to fledge. It becomes too hazardous to drive them home having them hop around in the brooder. For the choughs we stopped once their eyes started opening. This particular species is prone to imprinting and for the reintroduction project it is imperative that they don’t imprint on the wrong thing.
Chough chicks at twenty days old. Photo by Liz Corry
For this reason we also wore a black glove and used red tweezers when hand feeding the chicks. This presented the chick with the rough image of a parent’s head and not a human hand. We want the chicks to have a certain level of tameness for the release process, but we don’t want them taking food from a tourist’s hand. It seemed to do the trick. They never stopped eating anyway. Chicks were weighed daily and, on comparison with wild chick data, by the end of May they were exceeding all standards.
Double-clutching efforts 2014
Chough chicks being hand fed with tweezers. Photo by Liz Corry
Whilst we did show that choughs can produce a second clutch if the conditions are correct, we failed to glean anything of use from those clutches.
As mentioned last month there were problems with parents discarding eggs and the loss (escape) of Arthur disrupted Issy’s attempts. We managed to rescue three eggs to set in our incubator. Unfortunately these suffered from the same problems as the last clutches. Insufficient weight loss leading to embryonic deaths. Hopefully, we can look back through the data collected this year and work out improved incubation protocols for next year.
Summary of hand-rearing programme
Chicks at four weeks old start being a bit more mobile and no longer fit in the brooder. Photo by Liz Corry
Statistically a 33% success rate from 13 eggs is not a great achievement and there are definitely areas for improvement. However, it is still an incredible accomplishment to have hand-reared four chicks from eggs all taken before parental incubation had really begun. It takes a lot of commitment and emotional investment on behalf of the keepers. A lot has been learnt that will not only benefit the chough breeding programme but the other species hand-reared at Durrell too.
Chough chicks take about 6-7 weeks before they leave the nest. Normally the keepers are used to seeing their hand-reared chicks fly within three weeks. This is double the effort and double the wait to see if these four chicks successfully fledge into well adapted juveniles fit for release into Jersey.
Health screening and DNAsexing
Chicks being taken to the Durrell Vet Department for routine health screens. Photo by Liz Corry
Chough chicks are hard to sex visually. It is based on bone measurements and body weights although individuals can vary. Common practice in captivity is to take a pin-prick of blood dotted on blotting paper and send it off for DNA analysis. All four chicks had samples taken and we will await to hear the results in June.
They had their first visit to the vets this month. All routine. We screen faecal and blood samples for various parasites and bacteria whilst the birds are held at Durrell. We will screen again once they are out at Sorel. It allows us to make comparisons and highlight any concerns which may require treatment to increase their chances of survival.
Whilst in the hand, each chick was implanted with a transponder. This has a unique code which allows individuals to be identified if rings are lost or maliciously removed as can be the case in the pet trade. The chicks didn’t seem too phased by their visit as they were eating as soon as they went back to their housing.
Sorel soft-release update
April saw the start of the 2014 soft-release for eight choughs up at Sorel. Very quickly eight became six with the mysterious disappearance of Yellow and Cerise after the first week (see April’s report).
After a week or so of opening and closing hatches each day, Red and the young male White grew in confidence and decided to join the others when they flew out of the hatches.
By May the six had started to fly as a group, feed as a group, and play in the quarry buildings as a group. But, when it came to returning to the aviary they still had their own ideas. Sometimes they would fly back in twos or threes. We could, with relative ease, shut them in to the back sections and reopen hatches waiting for the remainder to return.
When they returned as a group of six it often made it impossible to shut the hatches. There might be at least one bird on the roof on lookout whilst the others fed inside. Any movement like a passing cyclist or friendly team member approaching the hatches and an alarm call would send the group fleeing.
We also encountered the same problem as last year with the pair, Green and Mauve, who don’t like being shut in. They would bolt at the first sign of a keeper. Unless of course they were really hungry in which case their motivation to be outside was overruled by their stomachs. On the odd occasion of one of them being shut in, the other would hang around the aviary begging to be let in with them.
It was quickly becoming apparent that not all of the choughs liked being shut in. We did not want them to start viewing the aviary as a negative experience. The soft-release method had to be adapted. Instead of locking them in as they returned we waited until roost. At this point if the birds were in the aviary they were already fed, settled, and hopefully asleep and oblivious to the keepers. Hatches were reopened the next day and the timing brought forward by 30-60 minutes each day. So eventually the birds were being released at 8am then locked in again at 9pm.
It meant that the team faced a long day spending the last hour before roost accounting for all six birds, then lurking in gorse bushes or hedgerows while waiting until sunset. On a couple of occasions the radio signals indicated that all six were at the aviary, but due to fading light and roost boxes it wasn’t obvious to see exactly where they were. We would not know until sunrise. Twice we found a bird had spent the night in the external roost box on the side of the aviary.
On one or two occasions Mauve would roost in the quarry whilst her partner chose to roost in the aviary with the others. She would reappear at the aviary in the morning for breakfast.
By the end of May the birds had clearly settled into a routine and were adapting well to life outside the aviary. The hatches were finally left open so the birds could come and go as they pleased.
Radio-tracking sessions started to blur into feeding sessions as the birds quickly learnt what time of day to expect staff to be at the aviary. At the first visit at 7:30am you might find them probing the ground by the edge of the cliff path, but as soon as they catch site of you or hear the gate opening they take to the air calling and fly to the aviary. It would also happen during the day, providing they were hungry enough. This time of year there are plenty of insects around to keep them occupied. As well as other distractions/attractions (depending on your view) at Sorel this time of year.
Dispersal range of released choughs
With the exception of the missing birds, the released choughs have not ranged far from their release site. We know choughs can fly far if they feel the need to. Yet during the breeding season they tend to stick within a few hundred metres of their nest site. Our choughs are not exactly in a normal situation though. What is more they are entering into an environment with no other choughs for guidance (or competition) and a habitat that still needs improving.
Last year they quickly turned the quarry into their second home and would venture no further. In fact they didn’t really spend much time elsewhere except the aviary. The only ground they touched in between was Sorel Point.
In April it looked like it was going to be much the same. As the group cohesion outside the aviary strengthened and the birds became more confident it quickly changed. By May they were foraging the grazed land next to the aviary. Probing for insects in amongst the flock of sheep.
Choughs started exploring Crabbé in May but after several exploratory flights decided to stick with Sorel. Photo by Liz Corry
After a week or so of exploring this area they decided to take it up a gear. During the phase of releases when hatches were opened around 10:30 and closed at sunset the group spent a few days visiting Crabbé.
Like clockwork they would fly west when the hatches opened. At first just circling the valley before heading to 2km west then soon straight to their destination. By the time the radio-trackers had jumped in the car and driven round the group would be back at Sorel.
We pre-empted them one day by splitting up and stationing one person at Crabbé before the hatches opened. Sure enough they flew over and continued over the shooting range out of site. Very quickly they returned, flew around Île Agois, then back to the aviary. They did this three times within 60 minutes and never landed at Crabbé.
These were exploratory flights which obviously told them they were better off staying at Sorel as they soon stopped going. This could be for very several reasons. Firstly the raven chicks had just fledged. They don’t pose a threat to the choughs but the parents definitely didn’t want the extra company in ‘their’ air space. A more likely threat would come from the nearby peregrine parents with their newly hatched, hungry chicks. Gunshot from inside Crabbé’s shooting range didn’t scare the choughs but guaranteed they weren’t going to land on the sand bank and grassy areas. The big drawback would be current habitat. A lot of agricultural fields, bracken and other overgrown vegetation are not what the choughs are looking for. There is a small area of short grass around the cliff path approach, but at the time of the chough visits there were hikers and farm vehicles that would deter a first time chough visitor from landing.
What is interesting is their lack of desire to explore the Devil’s Hole side of the valley where the sheep roam. They can see the land from the aviary, but as far as the team know the birds have never touched down over there. Maybe in time when they deplete their insect supply at Sorel.
The choughs also seem to avoid exploring the rocky cliffs on foot and the lower grazed areas that slope down into the sea. Again this might be something that comes with time. For now they seem happy around the aviary. Free board and lodgings. Why look anywhere else?
Training finally pays off
When people hear about how the releases have ‘skewed’ off plan they are quick to assume that the behavioural training has not worked. A bird is a bird; it will do its own thing. In some respects this is true. They haven’t always returned to the aviary when the whistle was blown for dinner but it may not be because they don’t know what the whistle means. There are many reasons why they don’t return and each bird has its own reason.
Evidence that the training has worked came to light once the birds gained confidence and started settling into a routine of returning to the aviary at night.
The choughs are now frequently flying up from the surrounding cliff top when they hear the whistle and heading straight to the aviary. They then land on the target boards where the keeper has left the food. If the food is left inside the aviary they can be cautious and wait patiently on the netting above until the keeper has left. They feel less restricted when the food is left outside and can fly within inches of the keeper’s head following them from target to target.
This has also meant we can continue to record body weights when they land on the scales in just the same ways as when they were locked in the aviary.
An interesting indirect pay-off of the training this year has been evident when they have encountered peregrines. The peregrine nesting season has probably meant there have been fewer interactions with the choughs compared to August and September last year. When a peregrine has flown along the cliff path the choughs take to the air and return to the aviary. They have obviously learnt to associate the aviary not just with food but with safe shelter.
Annual moult
The odd feather seemed to be appearing here and there on the ground at the release site. With all six accounted for and looking happy and healthy it could only really mean one thing. They’d started moulting. A couple of weeks later than last year but nevertheless the countdown had begun. By next month it is likely they will have moulted their tail feathers and dropped their radio transmitters.
UFO sightings over Jersey
We had a report of an unidentified flying object at Mont Orgueil Castle on the 6th. Chris Durbano a site guardian for the castle emailed Birds On The Edge to say he spent Saturday watching what he thought to be a chough feeding around the grounds of the castle. The bird disappeared as the numbers of visitors picked up during the day, but reappeared at closing time. Chris was able to take a photo clearly showing a chough stood on the ramparts of the castle. We suspect from the rings that it was Arthur our breeding male that escaped from the wildlife park on 30th April.
We visited the castle as soon as we read the message, but with the sighting being three days previous he (Arthur) had had a chance to move on. A few days after, we received a call about a chough sighted in a garden at Les Platons. The description of the bird and its behaviour makes it likely that it was indeed a chough. The team were in the area within thirty minutes of the sighting, but there was no site or sound of a chough.
It is more than likely that after being in Gorey, Arthur made his way round the coastline looking for suitable feeding grounds and a safe roost spot. It would be ideal if he made it all the way round to Sorel or back inland to the Wildlife Park. This has yet to happen and we can only hope that he finds sufficient resources to continue his journey.
A plea was made to the Jersey public and colleagues on the neighbouring islands and France were alerted to Arthur’s escape and the missing released pair (see report here). We received a handful of reports none of which resulted in finding them. We are still asking the public to report sightings of choughs via email or by phoning Durrell directly. As more and more choughs are released we will become even more reliant on the help of the public. It might be a small island but the choughs have one advantage over us….they can fly!
Landscaping at the aviary
Strimming round the aviary. May 2014. Photo by Liz Corry
A big thank you to Johnnie McLaughlin, Ecoscape, and Sally Dalman and the National Trust for volunteering to cut the grass and weeds around the aviary. The hedgerows are once again overgrown with bracken and weeds. It has created a haven for rodents especially rats and has been creeping closer to the aviary. Something has been having a go at the aviary netting and we need to deter them. The short grass should also create a better environment for insects, especially ants, which the choughs love to eat.
By Liz Corry In 
