Update by Régis Perdriat of the LPO Station at l’Île Grande

Regis reports that in August and September this year there have been 2-3 red-billed choughs visiting the vicinity of the Station and Brittany’s Sept Îles Reserve. With 50+ pairs of choughs breeding in Brittany, the species’ nearest stronghold is Ile Ouessant (Ushant), the island at the western end of the Brest Peninsula.  

These sightings are not the first as in recent years there have been several choughs recorded in the reserve and in the vicinity of the Île Grande station:

• 1-2 birds were seen at the LPO Station between 18^th October and 6^th December 1987;
• 1 bird seen at the LPO Station 31^st October and 2^nd November 1994;
• 1 bird seen in August 1997 on Île Rouzic (the island of the Sept Îles with the gannet colony);
• 3 birds seen between the 8th and 20th August 2005 (one bird had been ringed on Ouessant in May of the same year and was back on Ouessant two months later);
• 7 birds were seen at the LPO Station on 3^rd October 2007 and 2 on the 17^th October;
• 2-3 birds seen regularly between the 20th August and the 17th of September 2012.

Interestingly there have been sightings of choughs even further north including birds at Cap Fréhel, Calais and even a juvenile at the Antifer nature reserve (Seine Maritime).

These records from l’Île Grande and the Sept Îles Reserve on Bittany’s north coast well show how much these birds may roam along the coast to the south of Jersey.

Report from Liz Corry

Captive choughs at Durrell

In the wild at this time of the year breeding pairs, juveniles, and non-breeding adults are coming together to form their winter flocking groups. In captivity this is replicated by moving all the birds into our large display aviary. However, due to the imminent re-introduction plans we are keeping the potential release candidates separate from the other choughs. So Operation chough-fle shuffle was put into place by the keepers this month.

The shuffle began with the breeding pairs being moved out from their aviaries to off-show holding facilities (LNQ). The non-breeding birds (release candidates) in the display aviary were moved down to the breeding aviaries. Then, finally, the breeding pairs could be moved into the display aviary.

To avoid any negative associations with their keepers the non-breeding birds were netted by non-uniformed staff and handled by different species’ keepers. Once in the hand all birds were weighed, had a general health check, and had blood samples taken by the vet for disease screening. A group faecal sample was taken prior to the catch-up for disease screening, which was also submitted as part of Durrell’s bi-annual screening process.  It took two days to catch up all six birds because they first needed to be lured into the shut-off cage before netting. After the first two birds were trapped the others became understandably wary of going in the shut-off, hence the two days.

With the display aviary empty and cleaned both breeding pairs were caught up once again and moved down into the display aviary. They were released at the same time to avoid one pair establishing a territory before the other. Observations were made by keepers for the first two hours after mixing and continued intermittently over the next few days to make sure everyone was harmonious.

As expected, last year’s dominant pair, Tristan and Issy, made their presence known and repeatedly flew around the aviary vocalising. This was matched by Arthur and Gwinny although they preferred to stay perched high. There were a couple of mid-air scuffles in which Tristan brought one of the other birds to the ground but these only lasted a few seconds. The birds are more confident in the aviary than they were last year and are more tolerant of the keepers being in the aviary. Arthur and Gwinny are always first down for insects: this could be seen as a positive thing if the birds are more confident. However, it might be that the other pair is stopping them from getting to the main food dishes when the keepers are not there. This behaviour is being closely monitored by the keepers.

As we prepare to return the red-billed chough to Jersey this recent summary of the bird’s disappearance from Cornwall and its successful return is very timely. See Cornish Choughs for the whole story.

Key dates

1800s: A marked decline in numbers of choughs in Cornwall due to persecution and habitat decline
1930s: Probably only half a dozen breeding pairs remain in Cornwall
1947: Last successful breeding recorded in Cornwall
1967: One of the last pair found dead
1973: Last chough in Cornwall seen in February 1973

1973-2000: A handful of records of choughs passing through, two birds arrived at Rame Head in 1996 and stayed for 6 months
2001: Choughs return naturally to Cornwall – a small influx of birds recorded and three birds settle at the tip of the Lizard peninsula
2002: Choughs successfully breed in Cornwall again
2006: Two pairs of choughs raise young in Cornwall. Also first documented record of colour-ringed Welsh choughs in England (seen in Somerset and north Devon)
2008: First chough chicks born in West Penwith, Cornwall, for 150 years
2011: Six pairs nest in Cornwall
2012: Seven pairs nest in Cornwall.

Has that natural recolonisation been successful?  These figures show the slow but steady increase in the number of breeding pairs and youngsters fledged from Cornish nests. Not all young choughs are expected to survive, these are long-lived birds with a high mortality rate, especially in their first year, but the survival rates of Cornish birds are very good compared to other UK populations.

Year    Pairs     Young fledged
2002   1            3
2003   1            3
2004   1            4
2005   1            5
2006   2            8
2007   2            9
2008   2            6
2009   5            8     Two pairs successful, two young pairs attempt to breed
2010   6            9     Three pairs successful, two attempt and one male pair
2011   6            15   Four pairs successful, one pair’s eggs predated, plus one male pair
2012   7            18   Five pairs productive, plus one young pair and one male pair

Reports from Liz Corry

JULY 2012

Captive breeding at Durrell

All of the choughs have started to moult: juveniles around the 11^th whilst the breeding pairs started a few days later.

Captive breeding at Paradise Park

The sexes of the three chicks bred this year have been confirmed as 1 male and 2 female.

AUGUST 2012

Captive breeding at Durrell

All the choughs are now being given their non-breeding/winter diet whereby the protein levels are reduced, i.e. the ox heart has been removed and less insects are given. In past years we have given mixed corn in winter as wild choughs are known to forage in cereal fields when insect numbers are low. However, the choughs in captivity at Paradise Park and at Durrell rarely touch the corn so it has been removed from the diet completely.

The breeding pairs have now finished for the season. Normally they would be integrated back into the display flock; however, due to the release planned for this autumn/winter we will keep the breeding birds separated from the potential release birds for now.

Display flock

The low productivity of chough chicks this year means that the trial release cohort will consist of the three chicks hatched at Paradise Park this year and another three selected from the older juveniles in the display aviary at Durrell. In preparation for their release these birds will be trained to fly to target boards for food as this will help with the supplementary feeding once in the wild and allow the keepers to call the birds back if they need to be shut away in the release aviary.

Training began at the end of July and looked promising at the start of August. The birds are accustomed to flying down for food, but they need to learn to respond to their cue for food. Working with a large group rather than training on an individual basis has proved challenging. We increased the number of target boards so that each bird has a chance of getting to food which in turn strengthens the learned behaviour. However, there are still a couple of individuals who hang back whilst the dominant birds fly down first and take all the food. We will continue with the training and looking at ways to improve the birds’ success.

Notes 

All the juvenile choughs have somehow managed to lose an ID ring. Five have lost their metal rings and the sixth has lost its plastic ring. One metal ring has been recovered and it looks as if it has been prised open. All six birds can still be identified but new (and improved) rings will be added before any release.