Chough report: May 2021

Broken and faded leg rings used on choughs. Photo by Liz Corry.

By Liz Corry

Housekeeping

Another ‘catch up’ with the choughs this month. This time BoPercyTrevor, and Chickay all needed replacement leg rings. It provided an opportunity too to check their general health through body weights and visual inspection of feather and body condition.  

Happy to report they all looked well and it’s always nice to reconnect with Chickay again who we hand-reared back in 2014.

In contrast, we declared six adults and four juveniles (< 12 months of age) as missing, presumed dead. A few had been missing for a while; in particular, the juveniles who in this species tend to struggle to get through their first winter. Others like Beanie Baby had suddenly gone from their territory making it more obvious to detect the loss. An updated ID list for the Jersey flock is available here. 

Mystery chough in England

Of course one or more of the missing list may have taken flight off-island. No COVID-restrictions for them! A chough of unknown origin was spotted in Dorset early on in May. The video below was taken at Portland Bill near Weymouth. There was a later possible sighting on the Isle of Wight.  

 

The bird in Dorset was unringed and likely to be a Cornish bird dispersing along the coast. Devon have carried out a lot of habitat management to try and encourage choughs to disperse east from Cornwall, which might have helped this one to reach Dorset.

Whilst doubtful it was a Jersey traveller; I contacted the Portland Bird Observatory just in case. All our captive-bred released birds are fitted with transponders. A quick scan with a pet microchip reader would detect if a transponder had been fitted. This requires the bird to be in the hand, a long shot for Portland, but at least they now know about our project and can bear it in mind next time they have a surprise visitor. 

Choughs travel with Blue Islands airline

England did receive one influx of Jersey choughs this month though. The three males we bred in the Zoo last year finally secured passage to Paradise Park, Cornwall. Ever changing COVID travel restrictions in both the UK and Jersey had placed the export on hold for several months.

Pre-export checks include checking the chough’s transponder number matches the paperwork. Photo by Liz Corry.

Export routes are limited now because only certified ports are permitted live animal transfers. Portsmouth (ferry), Heathrow and Gatwick (plane) are the usual routes we use to transfer zoo animals between the UK and Jersey. Neither were an option this time around and after a lot of ‘blue sky thinking’, red-tape cutting, paperwork signing, and (I imagine) a magic 8-ball, our Animal Registrar managed to open up a route via Exeter. This relied heavily on the generosity of Blue Islands airline who have previously supported Durrell’s work. Port staff handling the transfer at Exeter were equally helpful and handed over the birds to David Woolcock who then drove them down to Hayle.

Once they clear quarantine, these males will join the non-breeding flock housed at Paradise Park and eventually be paired up for 2021. They may even find themselves travelling back past Exeter on to one of the planned reintroductions in Kent or the Isle of Wight.

Hatching underway in Jersey

The wild Jersey breeding pairs became very active at Sorel as hungry bills started to hatch out. We think that the first nests to hatch belonged to  Betty and Pyrrho and Percy and Icho. The males would be waiting at the aviary for the supplemental feed, snatch what they could and zoom back to their quarry nests. They would then return with the females to repeat procedure and spend the next hour or so flying back and forth roughly every five minutes.  

Females tend to stay on the nest for the first week post-hatch when the chicks are most vulnerable. Once they get their body feathers, mum will help in collecting food such as ant eggs/pupae, beetle larvae and, in Jersey, the supplemental diet of mealworms. 

Ronez Quarry reported a new nest in a building the choughs have not used before. We suspect this is Betty and Pyrrho since her last known nest site no longer exists. Ronez also sent through photos on 11th May confirming Dusty and Chickay had succeeded in hatching three chicks. These were the first to be accessioned in 2021 and given temporary names of PP066PP067, and PP068. Whilst not the most attractive of names it signifies that they are the 66th, 67th, and 68th chicks to hatch in the wild since the reintroduction began. 

Chough chicks around 17 days old) in the quarry. Photo taken under license by Toby Cabaret.

I should add that some chicks hatch out, die, and get discarded from the nest without us knowing, therefore, the total number hatched is likely to be higher. The same day we were given the good news about Dusty’s family, Ronez called again to say they had found three other chicks prematurely out of their nest.  

The nest these chicks were from is in a box in the secondary crusher building used by Green and his new partner Vicq. Standard procedure would be to return the chicks to the box and hope the parents continue to feed. This option was off the cards as access to the box requires a scissor lift and at 5pm, with hire companies closed, we had to think outside the box. Sorry, even I just sighed at that pun.  

Luckily Ronez had a spare nest box which they placed on the elevated walkway inside the building. One chick was wobbly to say the least when he was picked up. The other two seemed ok despite the fall. Whilst not ideal it meant the chicks were off the ground out of the way of gulls, predators, and morning site traffic. 

Unfortunately, the three chicks did not survive the night. I collected the bodies on the way to work for the Durrell vet to carry out post mortems. He believes at least one was still being fed by the parents judging by the quantity of undigested mealworms he found.

We don’t know how or why the chicks found themselves on the floor. I suspect the nest box is too small to provide adequate air flow in that quarry building which can lead to over-heating, aspergillus, and/or compromised breathing. We had planned to replace the box with a bigger one for the 2020 breeding season. Lockdown stopped that then and again in 2021.  

Even more of a mystery was what happened next with Green and Vicq. The day after the nest failed, Green was seen flying around with his old partner Pyrrho. Then Vicq reunited with her ‘best friend’ Lily who she spent most of 2020 preening and hanging out with.  

Plémont hatch-trick

Plémont Bay. Photo by Liz Corry.

We all needed some good news after that which is where the Plémont pair come in. Minty and Rey started behaving like new parents desperately looking for food around 14th May. There is sparse foraging habitat within the immediate vicinity of the nest. 

Bracken smothers most of the land in the immediate vicinity of the Plémont chough nest. Photo by Liz Corry.

However, 800 metres away at Les Landes there are fields grazed by horses and the racecourse next door. The male could be seen making regular visits to this site whilst the female remained with the nest. 

The Plémont pair source food for their chicks from paddocks like these around Les Landes. Photo by Liz Corry.

On a visit to the nest on the 19th, I heard the unmistakable sound of a begging chough chick. Too young to be visible. The parents on the other hand were visible. Especially if the raven family flew past. Minty has done a sterling job of keeping the nest predators away shouting at any who dared to go near.

Choughs are expert rock-climbers. Photo by Liz Corry.

By the end of the month, we had visual confirmation of chicks in the nest. Minty and Rey were still busy feeding and nest visits every five minutes gradually changed to every twenty minutes or so as the chicks grew and gained strength. The site of a parent carrying away a faecal sac from the nest is a joyous one. To a select few I guess. We are extremely excited to see what June has in store.

Rey, the female chough brooding chicks at Plémont. Photo by Liz Corry.

 

Leave a Reply