By Liz Corry

Fledging

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.

By Liz Corry

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 2^nd 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.