Chough report: July 2016

by Liz Corry

“The Guide says there is an art to flying”, said Ford, “or rather a knack. The knack lies in learning how to throw yourself at the ground and miss”.
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Wild and captive-bred chicks fledged and took flight this month. Photo by Liz Corry.

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

Captive-reared chicks

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

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

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

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


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

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

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

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

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

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


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

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

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

In the meantime…

Durrell’s breeding pairs return to their flock

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

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

Quarry capers

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

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

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

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

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

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

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

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

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

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

Veterinary intervention

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

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

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

Dusty, Egg, and Chickay

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

Summer finally arrived…for a day

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

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

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

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

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

Preparations for release

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

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

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

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

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

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

Final preparations

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

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

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

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

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

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

Operation Chough

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

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

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