By Liz Corry

Celebrations and commiserations this month as the chough breeding season begins to wind down. We have only managed to produce two chicks this year through the captive breeding programme at Durrell. It doesn’t mean that we have had to work any less, however, to ensure that these chicks make it to fledging.

Hand-rearing Gwinny’s chick

Gwinny’s chick is being hand-reared by Durrell staff. Photo by Liz Corry

The chick we began hand-rearing in May continued to grow and develop with relative ease. We had a few stressful days trying to keep the chick from overheating. Corvid chicks are prone to overheating when developing in the nest. We had been carefully controlling temperature within the brooder and maintaining a constant room temperature. The problems started when the weather outside improved. Late afternoon to early evening is when the sun is shining directly on the incubation room window. For a couple of days  at the start of June the temperature in the brooder was being pushed up 2-4°C higher than it should have been and the chick would pant excessively. Much like the perils of keeping dogs in hot cars the chick could have easily died. Of course we wouldn’t let that happen.

A makeshift net curtain was put up to shade the chick in the evening and the windows were opened. As this was happening out of hours, open windows posed a security risk, so we stayed with the chick in between the two affected feed times whilst doing our best to cool it down.

Hand-reared chick in the rearing room. Photo by Liz Corry

Fortunately this situation did not last long and a couple of days later, at 17 days old, the chick was large enough to move out of the brooder and into our rearing room.

Here we had to make sure the room conditions best prepared the chick for the imminent move to the release aviary.

Heating was turned off and skylight windows were gradually opened to allow for a breeze to blow through the room. Not quite cliff top conditions, but at least the outdoors will not come as too much of a shock.

There was some preparation to do at the aviary before the chick moved in. The doors and hatches to section 1B (where the rearing box is) were closed a few days before. This allowed the free-living choughs to sort out their new living arrangements. Eight of the juveniles roost in the aviary and we know from droppings that some use section 1B. There are plenty of other options within the aviary, they just need to decide amongst themselves who was going to go where. It also allowed us to check there were no rodent issues to compromise the chick’s success.

We also spent two days strimming, chopping, mowing, and bracken bashing. Basically any job that was going to create lots of noise and disturbance we wanted out-of-the-way once the chick moved in. At least until it had fledged and was more comfortable in the aviary.

Choughs forage around the outside of the aviary looking for insects amongst the recently strimmed grass. Photo by Liz Corry.

With these tasks out-of-the-way we picked a day when we had plenty of staff around and the vets were available to examine the chick. On 22nd June we took the chick to the Vet Centre to have a routine health-check and blood samples taken. We also added plastic leg rings and implanted a transponder. A DNA sample was taken and sent off to discover the sex of the chick.

Vet, Alberto Barbon, examining the chick’s eyes…or is it the other way around? Photo by Liz Corry

A transponder microchip being implanted into the chough for indentification purposes. Photo by Liz Corry

The one thing we had not planned for was the torrential downpour which lasted most of the day. The chick was fine, being kept in either a pet carrier or sheltered in the aviary. We didn’t fare too well, even with waterproofs, giving up by lunchtime. The chick seemed to adjust easily regardless of weather and took food from the tweezers straight away. When the adults arrived for their food it was a little intimidated. By the afternoon it was calling in response to the adults calling. The video below includes a clip taken on a smartphone the day the chick moved in. The adults are outside on the netting calling and looking in to try to see where the noise was coming from.

The next couple of days the weather switched to being really nice. This time too nice and the chick was overheating again. We might name the chick ‘Goldilocks’ depending on the DNA results. Temperatures in the nest box were averaging 21°C, 2-3 degrees higher than the chick was used to. We removed one of the corotherm panels on the side of the aviary next to the box to allow the wind to get through which helped a lot.

The adults have found their own way to cool off this month using the sheep water bowsers in the field next door, or flying around the quarry where the temperatures were cooler.

Choughs post-bathe using the water pans left out for the sheep. Photo by Liz Corry

Water bowsers left out for the sheep are used by the choughs as well. Photo by Liz Corry

The underlying issue was that the chick was stressed by the whole situation. Anything additional, like it being too hot, would feel amplified for the chick. Last year the four chicks we moved in had each other to look to for reassurance. As one person described it “remember what your first day of school was like”. The chick can hear the intimidating ‘big kids’ next door and sometimes see them. We appear with food for reassurance then disappear (we don’t want it imprinting on us).

The hand-reared chick fledged in the release aviary at Sorel. Photo by Liz Corry

Feed times instantly doubled in length. The chick would eat a few bites then get distracted by noises outside of the aviary. During this time it would take food from the tweezers but then spit it back out. It meant it wasn’t eating as much as it had been back at the park and it’s body weight was fluctuating daily.

Captive-reared chough chick exploring outside of the nest box (top right corner). Photo by Liz Corry

When the chick started ‘bouldering’ out of the nest it became even harder to feed with all the new things for it to explore.

If it wandered too far from the nest, most notably onto the top step of the ladder, it would stay there until Harriet or myself guided it back up with the promise of food.

The captive-reared chick investigating its new home. Photo by Liz Corry.

By July the chick should be flying around with confidence and eating for itself.

We are hoping to receive a group of parent-reared chicks from Paradise Park who can then be socialised with our chick.

We will assess nearer the time whether this chick is suitable for release. If it ends up being too dependent on staff we might not release it and find an alternative role for it back at the park.

Gianna and ‘Special K’ the foster chick

Day old chough chick. Photo by Liz Corry

In May we gave Gianna, our tame chough, a chick that we had hand-reared for the first five days after hatching.

Our intentions being that this would be less demanding for staff time compared to hand-rearing.

More importantly the chick gets to be raised by an actual chough and less human contact.

As this was the first time we had attempted foster-rearing, the only surviving egg of Tristan and Issy, and if a successful release candidate to be name something beginning with ‘K’ we decided to give the unsexed chick the nickname ‘Special K’.

Gianna proved to be an attentive first time parent doing everything a mother chough should.

Staff provided Gianna with a regular supply of food from 07:30 until 19:00, sometimes feeding her in the nest as the male would. As always, we ‘preened’ Gianna, but never Special K as that was Gianna’s job. At two weeks old we switched from daily weighing to every few days as it became too much of a disturbance. The chick had become more alert and reactive.

On 30^th May I noticed Special K looking a little unsteady in the nest. I took it out to weigh and instantly saw to my dismay that it’s right leg was bent. Until now the twigs in the nest had blocked our view of the chick’s legs when sat in the nest. When we had handled it there was nothing to suggest there was a problem although we don’t spend long with the chick when weighing to avoid prolonged human contact.

A deformity in the right leg of the chough chick Special K causes it to walk with a limp. Photo by Liz Corry.

The weekend duty vet was called out to examine the chick. There were two possible reasons either the chick had sustained a fracture in the nest and healed incorrectly or, more worryingly, it was metabolic bone disease (MBD) where bones are weakened.

MBD can be induced by inappropriate nutrient levels in the diet namely lack of calcium and/or vitamin D3.

Gianna had been feeding the chick a lot of waxmoths. Her favourite food, but not necessarily one packed with the right nutrients.

A blood sample from Special K was sent away to look at calcium and protein levels amongst other things. The results did not ring any alarm bells although we had to bear in mind the sample was taken after the bones had changed and would not necessarily reflect what was happening in the blood prior to this.

Special K, the foster chick out of the nest but not yet at the stage where it can fly. Photo by Liz Corry

The aviary they are housed in came into question as it is quite shaded in the mornings but full exposed by late afternoon. Lack of exposure to sufficient ultraviolet light can also cause MBD.

For a species which nests in caves and crevices you would expect UV levels to be lower in general compared to say a gull nesting on a chimney top. We were not too sure if UV levels would be a contributing factor.

Out of curiosity we took UV and lux (illuminance) readings at three different locations in the aviary and one in the overspill car park (no shade) over a five-day period. We did find that levels inside the nest box were low or zero compared to elsewhere. However, we don’t have data for wild nest sites or other captive breeding aviaries for comparison so we cannot read too much into this.

One way we would know whether it was MBD or a fracture would be to X-ray. We decided to wait until the chick was independent of Gianna to do this. Any intervention resulting from the X-ray would be better managed at this stage in its life rather than earlier. If it proved to be a fracture it might be possible to reset the bones in which case 5-6 weeks of post-operative care would be required.

Gianna feeding her six week old foster chick. Photo by Liz Corry

Special K was returned to Gianna and stayed in the nest until it started bouldering, i.e. jumping in and out of the nest, on the 10^th June. Special K’s mobility issues meant it took the chick a few days longer than normal to pluck up the courage and skill to get out of the nest.

We aided it by providing a shelf (B & Q’s finest budget pine) to the front of the nest.This way it didn’t have to leap far.

Once it was out it wasn’t long before it was taking short flights and keepers would find it above their heads hanging out on the safety-porch roof.

The bald patch of skin on the chick’s throat is due to Gianna feather plucking. Photo by Liz Corry

It started feeding for itself around 47 days of age. You could sense Gianna was beginning to feel bored and superfluous. She started preening keepers’ hair and demanding more of our attention. Rather worryingly she started feather plucking the chick under the bill. We tried to provide enrichment, otherwise known as distractions, but to little effect. Any other bird would readily take to them. Gianna either ignored or, in the case of the insect culture we spread out for her to probe through, she tidied it all up and dumped it in the corner of the aviary!

On 30^th June the chick was taken to the Vet Department to have X-rays taken. They clearly show the bone deformity along the tarsus which cause the right foot to bend inwards. This could be operated on to straighten the foot and avoid pressure sores and other problems developing in the future. The X-ray revealed a second problem; the femur was also abnormal to such as degree that it would not be possible to fix. This deformity would mean that once the foot was straightened the right leg would be slightly shorter than the left. This would put the chick at a disadvantage on the ground in terms of mobility, but not necessarily impact on its feeding and flying capabilities.

Vet nurse Mel Frost monitoring the chick’s respiratory rate. Photo by Liz Corry

Once vet nurse, Mel Frost, had prepped the bird for the operation the vet, Alberto Barbon, began to operate on the tarsus.  In simple terms the bone had to be broken and then reset using pins to hold it in place. These then stay in place for three weeks until the bone has fused together.

What I am about to describe might seem fairly gruesome to those of a sensitive nature. I have seen my fair share of operations, but as a surrogate ‘parent’ looking on even I found it a challenge. That being said it is astonishing what can be achieved through modern veterinary practice and as an observer you become transfixed.

Any operation in which a small bird is anaesthetised carries a risk. With this particular procedure there was another hazard. To break the bone internally the vet risks damaging tendons and nerves with the scalpel. Externally it is a lot cleaner with regards to infection risk, but the break might not be clean and could fragment. The vet opted for the latter and with precision and strength (and courage!) snapped the bone.

Vet Alberto Barbon and vet student Ben Howitt operating on the chough chick. Photo by Liz Corry

Pins were inserted by pushing through the skin at calculated points along the bone. Again this required a lot of precision and concentration. In total four pins were inserted along the length of the bone.

Inserting pins into the tarsus bone. Photo by Liz Corry

These were then braced either side with another pin and each join wired then glued together. Finally the ends of the pins were trimmed so the frame was less cumbersome to the chick once it was up and mobile.

The metal framework was wired and glued then trimmed to size before a protective gauze covering is applied. Photo by Liz Corry

Throughout this the vet nurse had paid close attention to heart rate and breathing rate. Painkillers were being administered and a precautionary antibiotic given. To the chick that is! Vet and staff had to grin and bear.

The positioning of the foot was corrected once the metal framework was in place. Photo by Liz Corry

Two hours in and the vet had reached the stage where he just need to bandage the framework to protect the chick. The vet nurse started to bring Special K around, out of the anaesthetic. Suddenly the chick’s responses changed and staff jumped into emergency mode. The chick had stopped breathing and heart rate had dropped. An avian form of CPR was started and adrenaline administered as a final attempt to restart the heart. Despite every effort Special K did not recover and sadly pronounced dead on the operating table.

Everybody involved was understandably devastated. It had seemed so promising with preparations underway to set up a vet centre cage for it’s post-op recovery just as the news broke. Having been hand-reared and foster-reared by staff for two months the loss of Special K had a greater impact than simply one less chough to release.

We now know via the post-mortem that Special K was a female.

Special K will always have a special place in our hearts. Photo by Liz Corry

Teaching Through Nature

For a second year running we participated in Alderney Wildlife Trust’s Teaching Though Nature programme. This is an exciting cross-curricular education project offering schools the opportunity to bring nature into their classrooms.

Using the dramatic lives of seabirds and Alderney’s wildlife, this project links directly to the Keystage 1 & 2 curriculum, and is an effective way of teaching science and literacy skills, and promoting pupil creativity and confidence.

For two weeks at the start of June Durrell took over with daily blogs and live webchats about the choughs, Birds On The Edge, and other species Durrell works with. Questions came flooding in; what do choughs eat?, how many choughs do you have?, what is the deadliest bird? We also had lots of lovely feedback and have hopefully helped spur on the next generation of conservationists.

Summer time shenanigans

With summer finally arriving there were changes in the air at Sorel. Some quite literally. The sheep have been sheared to lose their winter coat. Aaron and Ewen rounded them into the aviary field and spent four days working their way through the flock. The streamlined brown sheep are now back out on the cliffs and making new friends.

Three of te raven family with the seep at Sorel. Photo by Liz Corry

The fledged raven family have been spending a lot of time at Sorel in amongst the sheep, patrolling the field edges for food, and generally just hanging out on the cliffs. Considering the size difference, the choughs were probably pushing their luck when they mobbed one for being in their air space. Other than that they have been living happily side by side. The peregrines have been out and about. Thankfully no encounters with the choughs…yet.

With the warmer weather and calmer winds the choughs have largely ignored everything else going on at Sorel and simply concentrated on having fun. Flying high, tumbling, and playing on the thermals.

If you ever wanted to know why the collective noun for choughs is a chattering, here is why…

Nesting advances to the next stage!

By Liz Corry

The merry month of May held true to its poetic title this year and bore witness to the return of breeding choughs in the wilds of Jersey. After the flourish of nest building activity and copulating in April we noticed a change in the adults’ behaviour. Mauve and Blue were often absent or late to the feeds at the aviary. Their respective partners White and Green would be there, hurriedly eat, and then fly off towards the nesting sites. For those of us monitoring the nest sites it was quite tricky to see what was happening. Why? Because they decided to nest in Ronez Quarry!

We could only watch the birds as they flew back and forth between Sorel and the quarry and calculate how much time was being spent at the nest site. This is actually quite useful because as, breeding behaviour changes, so does time allocation at the nest.

Green and Blue head back to the aviary for food whilst White flies back to see Mauve in the quarry…maybe. Photo by Liz Corry

We know patterns of time allocation from breeding behaviour in UK choughs, especially Cornwall where nest monitoring is carried out every year as a form of protection as well as research. The female incubates the eggs and is fed by the male on the nest with the odd flight during the day to stretch her wings and get more food. Once those eggs hatch there isn’t much difference in behaviour as she spends the first week or two brooding the chicks. After which point the chicks are bigger and require much more food so both parents go out and forage.

White foraging alone at Sorel. Photo by Liz Corry

At the start of May we observed the males frequently making solo flights between the nest sites and headland. Combined with the females’ absence along the clifftops it suggested they were incubating!

The really interesting behaviour was watching the male feed at the aviary when we added the supplementary diet. He would then fly back to the nest site, seconds later the female would emerge and then fly together to the aviary. It was as if she was waiting for him to confirm that dinner was ready so she didn’t have to waste energy flying back in case we weren’t there.

I have to say this behaviour was most prominent between Green and Blue. White and Mauve did something similar, but alas White’s young mind would often wander and he would easily be distracted on the flight back if he bumped into another chough, especially Black, the female he was still courting. Mauve had to put a lot of effort in and was often seen at the aviary begging frantically for food from either White or the team.

We decided to increase the amount of food we were supplying since everything was being eaten and the females were obviously needing to maintain their energy stores. The juveniles on the other hand just thought Christmas had come early and revelled in the extra food. We do exactly the same for captive birds at the Park if they are polishing off their food. Our consideration for Sorel, however, is whether this means there is enough food and/or sufficient foraging habitat for choughs during the breeding season. We don’t want the choughs to become reliant on the food we give them. At the same time the fact that we have choughs incubating in the wild for the first time in a century means we would not want to risk starving the birds.

The pattern of behaviour with the breeding pairs continued for three weeks; choughs incubate for 19-21 days. Then change was in the air. On 22^nd May, I received a call from the Quarry, one of their staff reported hearing a ‘cheeping’ noise from Mauve’s nest! We had already paid a visit to the quarry to see exactly where the nest sites were, so we knew that it would not be possible to visually confirm chicks without disturbing the nest. Instead we had to rely on behavioural patterns again. Over the next 48 hours we started seeing Mauve spending more and more time away from the nest site. Due to the Bank Holiday weekend we were not able to access the nest until the Tuesday by which time we were confident that Mauve had abandoned.

White and Mauve at the aviary after their nest failed. Photo by Liz Corry

With assistance from Ronez staff I climbed up and checked in the nest hoping to find something to indicate what had happened. It was spotless.

Impressive engineering from Mauve and White led to one of the first wild chough nests in Jersey in a century. Photo by Liz Corry.

Our choughs have used fibre glass insulation found in the quarry as well as sheep’s wool to line their nests. Photo by Liz Corry.

A perfect nest with twigs, sheep’s wool, and fibre glass insulation (apologies Ronez for any damage to property).

On a more positive note Green and Blue continued as normal and we wait anxiously. I can only hope that the fact their pair bonding is stronger and they are that little bit older means they will have more success.

Dingle and Red

We mentioned last month that Dingle had paired up with Red and started nest building. They are still a pair but never really got anywhere with a nest. Having spoken to quarry staff it appears we had four females trying to nest in various places around the quarry. Moving twigs from site to site with only two finally feeling happy with their choice. This is an amazing achievement for their first year breeding and first year living free in Jersey. It bodes well for the 2016 breeding season.

News from the Wildlife Park

Back at the Park we had a much clearer idea of what was happening. On 1^st May a very punctual chick emerged from the egg that was being artificially incubated. We hand-reared it for the first five days feeding it from 6am until 11pm using the same methods as last year. This time round we were faced with the problem of rearing a chough in isolation. Last year having four chicks together meant they would be socialised and learn from each other exactly what a chough looks and sounds like. With a single chough the chances of imprinting are much higher.

Senior keeper Catherine Francescon feeding the day old chick. Photo by Liz Corry

Staff gently clean chick’s bill after feed. Photo by Liz Corry

We decided to try foster-rearing using Gianna as mum. This was not without its own risks. What is she didn’t take to the chick? Would she know what to do? Would she be able to feed it enough since she had no partner to feed her in the nest? The answer to the latter was easy. We became her partner. We would go in and feed her and if needs be feed the chick as well, but, ideally, she would do it to feel sufficiently bonded with the chick. The first question was the tough one and there was only one way to find out.

When the chick was five days old we moved it in with Gianna. I went in to feed and preen (tickle) her then swiftly switched her egg for a chick. What happened next melted the heart, she went to the nest box as I pretended to leave. I didn’t want to disturb her so walked to the other side of the aviary and watched carefully. She went to sit back on the ‘egg’ then hesitated, looked down puzzled, looked outside (I won’t say ‘at me’ as that is far too romanticised), then very carefully sat down and brooded the chick. The clip below was taken at a later date when Gianna was more confident.

I sat by the safety porch out of sight but still inside in case things turned nasty. It was silent for exactly 28 minutes, then movement.

Gianna removing a feacal sac produced by the chick. Photo by Liz Corry

Heart in mouth I watched, half expecting to see a bill appear with a chick dangling down. Instead it was a faecal sac belonging to the chick. Gianna flew out and across to the opposite corner of the aviary, deposited the faeces, cleaned her bill, then flew back to the nest. Now maybe this is something only a bird keeper can appreciate, but this was one of the most satisfying sights to see.

The next hurdle was seeing if she would feed it. It wasn’t a smooth start. Gianna knew it needed to be fed, she knew exactly what call to make to encourage the chick to beg, but she couldn’t quite work out how she got the food from her bill into the chick’s. It took three feeding attempts throughout the morning as she teased the chick with food overhead. To be fair, a single chough chick in a nest wobbles around a lot when its begging making it a very fast moving target. By the fourth feed something switched on and she figured out what to do.

We continued to support the chick by hand-feeding pinky mice and papaya, but since Gianna did such as great job we left her to it after a few days. We still went in six times a day from 7.30am until 7pm making sure she had enough supplies and, being Gianna, enough attention.

Gianna collecting inscts to feed to her foster chick. Photo by Liz Corry

The foster chick had daily weigh-ins for the first three weeks to monitor its progress. Photo by Liz Corry

It takes 41 days for a chough to fledge so pretty much the rest of May was spent just making sure the chick grew strong and healthy. Once this chick has fledged and is independent from Gianna it will be moved up to Sorel to take part in the 2015 release this summer.

Gianna keeping a watchful eye on her foster chick whilst making sure she is pampered properly at the same time. Photo by Liz Corry

Gianna’s foster chick was the only egg to hatch from Issy’s clutch of five. They re-made their nest but never got around to laying a second clutch for reasons unknown. The second egg being artificially incubated was the one rescued from Gwinny, or more accurately from the Dad who had an aversion to eggs. This pair also failed to lay a second clutch so it was really important that their egg survived.

The incubation period or this egg was an anxious one. It’s weight-loss graph suggested it wasn’t going to survive. Bird Staff worked hard to reduce humidity keeping the incubator and room as dry as possible. In the end a very delicate and nerve-wrecking procedure of drilling a small hole into the shell was carried out. This had the desired effect after which point it was a case of sit and wait. Not long past the due date the chick inside started to chip away at the shell and eventually emerged.

Gwinny’s chick being hand-reared by staff. Photo by Liz Corry

It has responded very well to life outside of the shell and is piling on the pounds in a good way. It now consumes about 20% of its body weight per feed, which equates to a lot of insects. As with the foster chick we hope this one will make it up to the release aviary this summer.

The video below was taken when Gwinny’s chick was only a few days old and had not opened its eyes yet. When the eye slits start to open we feed wearing a black glove and using orange tweezers. The iPod is used to playback the sound a female chough would make at the nest to announce she has food. It isn’t always necessary if the chick is already begging.

Guided chough tours now offered…by choughs. Photo by Harriet Clark.

Moulting begins

We started noticing moulted feathers in the aviary at the start of May. A few days later the choughs at the Park followed suit. For the Sorel choughs this meant that the remaining radio-transmitters started to drop off.

Their batteries are still active so we should be able to find them (unless they fall in the sea). If you are visiting Sorel and happen to find one please pick it up and contact one of the team we can refurbish them for the 2015 release.

Veterinary intervention

Durrell vet Alberto Barbon examining Mauve in the aviary. Photo by Harriet Clark

Digital microscope image of a chough faecal flotation The large dark oval shape in the top left of the image is a syngamus egg. Photo by Ann Thomasson

Shortly after Mauve abandoned her nest we noticed that she started looking a little run down and began sneezing and spluttering quite badly. She was caught up in the aviary and looked at by the Vet. Faecal samples showed she had nematodes and she was under weight. Highly likely to be stress-related, we kept her locked-in for a week and a treatment of Ivermectin. When she was looking better we released her back into the group.

Durrell’s Display Aviary

Thanks to a very kind private donor work can now begin on the renovation work for the display aviary at Durrell.

As you can see from the photos it isn’t an easy job and will take several weeks. Once ready we will once again be able to flock the choughs together over the non-breeding season.

Dismantling netting frame of chough display aviary. Photo by Glynn Bower

Work began this month nf repairing and redesigning the display aviary at Durrell. Photo by Glynn Bower.

And finally…

The Institute of Zoology held a symposium in May entitled ‘Health and disease in translocated wild animals’. Organised by Tony Sainsbury and John Ewen (ZSL), Katherine Walsh and Ian Carter (Natural England), and Matt Hartley (RSPB) the two-day symposium reviewed the impact of disease on species restoration through translocation, and considered lessons learned to guide effective planning and implementation of future translocation projects. Health management of conservation interventions was discussed, including methods of disease-risk analysis, evaluation of disease management alternatives, use of molecular tools to unravel disease risks, mitigation of diseases and methods for post-release health monitoring.

Day 2 of the symposium held at ZSL. Photo by Liz Corry

To kick off the second day Prof. Carl Jones, chief scientist at Durrell, talked about managing behaviour; appropriate socialisation and early learning to enhance survival using our choughs as a case study.

Bean, Dingle and company fulfilled their flagship role that day and brought the Birds On The Edge project to the attention of a international crowd. In a good way I might add!

Proceedings of the talks will eventually be published in EcoHealth and made available upon request.

Here is a tweet from one of the participants: