We announced the hatching of four chough chicks in April and May. DNA results, from blood samples taken in May, came back this month showing that we have one male and three females. We had guessed as much based on body weights when they were a few weeks old. Males tend to be heavier and of a slightly larger build.
In addition to this we built on their individual identities by giving them names. We intend to name any chicks reared for release on an alphabetical basis and with relevant names. They might not seem obvious choices to a non-Jersey resident but we think they are fitting names.
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 2nd 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.
The last few months at Sorel have been a busy time not only for the choughs, but also their neighbours; the resident flock of Manx Loaghtan sheep. The sheep play a vital role in the restoration of Jersey’s coastline, as their extensive grazing helps prevent the spread of invasive scrub and bracken, opening up areas for more sensitive plants to grow, which allows a mosaic of heathland vegetation to develop. The habitat created by the sheep supports a wider variety of wildlife, particularly specialist invertebrates and birds, and, therefore, helps restore biodiversity (see Grazing for background). The conservation grazing project is a partnership between The Reserve and the National Trust for Jersey.
Manx Loaghtan are extremely hardy sheep which thrive on coastal cliff tops, so are very well suited to their important job of grazing the area of coastline between Sorel and Devil’s Hole. They were introduced to the north coast by the National Trust for Jersey in 2008, and since then the flock has increased in number from 20 to 231, and the habitat where they are found has visibly improved, with bracken much less dominant in the areas they frequently trample.
The flock is managed by local shepherds Aaron le Couteur and Sam Hilton (CS Conservation), not forgetting of course their sheepdog Mist. Every day of the year the shepherds do a head count and visual health check of the entire flock; this can be a very time consuming job as the sheep are somewhat adventurous and are often found scrambling along the steep cliff sides or grazing at the very bottom of the cliffs close to the shore. The adult rams are kept off site for safety, except for the less boisterous wether “Buck” who acts as the flock guardian. Despite common thought, the number of horns is not an indication of sex, with both ewes and rams having 1, 2 or even 3 sets of horns.
The sheep breeding season begins in October, when the breeding ewes are taken from Sorel to the farm to meet the rams and, all going well, fall pregnant shortly after. The first and last months of pregnancy are very sensitive times, so the ewes are kept at the farm for monitoring, but in the interim the pregnant ewes often graze further ecologically important sites. After a five month gestation period lambing begins, with roughly half of the ewes giving birth to one lamb, and half to twins, which have a dark brown fleece that gradually lightens to a mousy brown. As with all sheep, Loaghtan ewes can occasionally have problems at lambing, so a few orphaned lambs were hand-reared by the shepherds this spring; an extremely intensive job as the lambs initially require 24-hour care and bottle feeding.
This year 121 lambs were raised, and after 3-4 months on the farm, they were moved up to Sorel with their mothers. Although the lush grassland of the farm may look ideal for the lambs, they are actually much better adapted to grazing on rough coastal scrub. Work for the shepherds doesn’t stop there though, as a couple of weeks later the ewes and lambs were rounded up for their vaccinations. After a just a few hours all 231 sheep were herded into the fenced off aviary field so that they could be checked and vaccinated, all the while observed by the choughs perched on the aviary roof, apparently quite interested in the spectacle!
Shearing is the next job, and the exact date depends on the weather conditions; Loaghtan wool is very high in lanolin wax, and in warm weather it becomes more viscous which makes shearing a much easier and faster job. The huge amount of wool produced is sold locally, creating extra revenue and reconnecting islanders with Jersey’s traditional knitting industry. Throughout the 16th-19th centuries the Island was an important exporter of knitted goods, so much so that the word “jersey”, describing a woollen sweater, is derived from the Island’s historical trade.
The final job for the shepherds during the busy summer period is weaning the lambs. When the lambs first arrived at Sorel in June they were still suckling, but once they reach over 12 weeks old they naturally begin the weaning process, ready for the ewes to be dried off. The lambs are, therefore, rounded up one more time and moved into aviary field for about two weeks, where they are out of sight of their mothers. Separating the sheep in this way allows the ewes’ milk to dry up and for them to put some weight back on, and the lambs to break the suckling habit in the least stressful way possible.
In addition to providing an extremely efficient habitat management service, the sheep also help produce essential feeding opportunities for the reintroduced choughs. Their grazing and trampling maintains short grass swards which the birds depend on for access to surface-active and soil invertebrates, and the sheep dung provides an important food source of beetle and fly larvae. Dung invertebrates might be particularly important for the choughs in spring and autumn when other insects are less abundant, or during dry periods when the ground is too hard for the birds to successfully probe into (see study by David McCracken here).
The maintenance of low intensity pastoralism is hugely important for the conservation of red-billed choughs throughout Europe, with several studies in the UK showing a significant relationship between sheep and chough populations.
Research on Ramsey Island, Bardsey and the Isle of Man (see IOM paper here) supports this link; in each case, reduced sheep grazing coincided with declines in the numbers of breeding choughs, and when grazing was resumed, the breeding chough populations began to recover. The choughs at Sorel certainly seem to show an affinity to the sheep, and can often be seen feeding in close proximity to the grazing sheep.
Please, therefore, respect the sheep and the important service they provide to our wildlife when visiting the area, and remember if you have a dog, to always keep it under control.
Following last winter’s successful Farmland Scheme, which engaged the help of many farmers in our efforts to stop the decline of local bird populations, we are pleased to announce that this year’s ‘Winter Bird Crops’ are being planted again across the island.
These specialised crops will be planted after the potato harvest and will produce a mixture of seeds and cereals. We have planted out such valuable crops as barley, mustard, quinoa, millet and sunflower (see advice here and free access paper here for importance of these crops). Throughout the winter these crops will provide food for the local birds, which, come spring, will repay this effort by feasting on the bugs and pests attacking the farmer’s commercial crops.
Thanks to a grant from the Co-Op EcoFund and the Countryside Enhancement Scheme, this year Birds On The Edge has been able to provide enough seed to cover twice as much ground as last year’s pilot scheme, to invite more farmers to join, and to expand to new areas such as St Ouen’s Bay.
We look forward to seeing the crops in full bloom and we will update you as soon as the birds start flocking to them.
New research has identified that the world’s most widely used insecticides may be a key factor in the recent reduction in numbers of farmland birds across Europe.
This new research represents a significant escalation of the known dangers of insecticides and follows an assessment in June that warned that pervasive pollution by insecticides was now threatening all food production.
Some, neonicotinoid insecticides, are believed to seriously harm bees and other pollinating insects, and a two-year EU suspension on three of the poisons began at the end of 2013. But the suspected knock-on effects on other species had not been demonstrated until now.
This new research, published in Nature, has revealed data from the Netherlands showing that bird populations fell most sharply in those areas where neonicotinoid pollution was highest. Starlings, tree sparrows and swallows were among the most affected. At least 95% of neonicotinoids applied to crops ends up in the wider environment, killing the insects the birds rely on for food, particularly when raising chicks.
The researchers, led by Hans de Kroon, an ecologist at Radboud University, in the Netherlands, examined other possible reasons for the bird declines seen during the study period of 2003 to 2010, including intensification of farming. But high pollution by a neonicotinoid known as imidacloprid was by far the largest factor.
“It is very surprising and very disturbing,” de Kroon said. Water pollution levels of just 20 nanograms of neonicotinoid per litre led to a 30% fall in bird numbers over 10 years, but some water had contamination levels 50 times higher. “That is why it is so disturbing – there is an incredible amount of imidacloprid in the water,” he said. “And it is not likely these effects will be restricted to birds.”
De Kroon added: “All the other studies [on harm caused by neonicotinoids] build up from toxicology studies. But we approached this completely from the other end. We started with the bird population data and tried to explain the declines. Our study really makes the evidence complete that something is going on here. We can’t go on like this any more. It has to stop.”
David Goulson, a professor at the University of Sussex, who was not involved in the new studies, said the research was convincing and ruled out likely alternative causes of bird decline. “The simplest, most obvious, explanation is that highly toxic substances that kill insects lead to declines in things that eat insects.”
There was little reason to doubt that wildlife in the UK and other countries were not suffering similar harm, he said. “This work flags up the point that this isn’t just about bees, it is about everything. When hundreds or thousands of species of insect are being wiped out, it’s going to have impacts on bats, shrews, hedgehogs, you name it. It is pretty good evidence of wholesale damage to the environment.”
Goulson said that, unlike the Netherlands, the UK did not monitor neonicotinoid pollution and the EU ban would not remove the substances from the environment. “They are still being widely used, as the moratorium only applies to three neonicotinoids and some crops. There is still a lot of them going into the environment. The door is far from shut.”
A spokesman for Bayer CropScience, which makes the neonicotinoid that was examined in the study, disputed the findings. “It provides no substantiated evidence of the alleged indirect effects of imidacloprid on insectivorous birds. Bayer CropScience is working with the Dutch authorities and agricultural stakeholders to ensure the safe use of imidacloprid-containing crop protection products and to preserve the environment.” He added: “Neonicotinoids have gone through an extensive risk assessment which has shown that they are safe to the environment when used responsibly according to the label instructions.”
But de Kroon said new research, including his own, was showing that neonicotinoids posed an even greater threat than had been anticipated and new regulations had to take this into account. In 2012, MPs warned regulators appeared to be “turning a blind eye” to the harm caused by neonicotinoids. David Gibbons, head of the RSPB centre for conservation science, said: “This elegant and important study provides worrying evidence of negative impacts of neonicotinoid insecticides on birds. Monitoring of neonicotinoid pollution in UK soils and waterways is urgently required, as is research into the effects of these insecticides on wildlife.”
A spokesperson from the UK’s Defra said: “Pesticide use across Europe is tightly regulated to protect the environment and public health – [pesticides] are a safe, effective and economical means of managing crops. We continue to review evidence on neonicotinoids.”
As noted here, in Jersey, very few of these products have ever been used. However, their use outside of the Channel Islands will undoubtedly have a bearing on our wildlife too.
The organisers of this year’s Inter-Island Environment Meeting cordially invite you to Jersey. This year’s event will be hosted by Durrell Wildlife Conservation Trust, the States of Jersey, Department of the Environment and the Jersey Biodiversity Partnership at the Durrell Conservation Academy on 9th and 10th October.
At this stage the organisers are still hoping to hear from anyone interested in speaking at the meeting. So, please contact the organisers by 31st July (e-mail address at bottom of page) if you are interested. Anyone wishing to attend the meeting should also contact the organisers.
Talks/presentations are invited from anyone. The first day’s focus will be on reports from plant and animal monitoring projects throughout the Channel Islands. We have presentations submitted so far on the Rare Plant Register, grass snake, wall lizard, common toad, Channel Islands seabirds, Jersey’s mammals and red-billed choughs. There are several slots available for further reports and we would like to hear from anyone wishing to give a presentation. Posters are welcome too.
We do not yet have a theme for Day 2 (Friday 10th October) so would be very grateful for suggestions and, again, offers for presentations. We will decide on a theme following suggestions and any submissions and hope to include contributions from Isle of Man, UK and France. Gérald Mannaerts Coordinateur PANACHE (Protected Area Network Across the Channel Ecosystem) is proposing to include a workshop relevant to this important project to include one or two of the most relevant subjects (citizen science, management of MPA, marine monitoring,…).
We plan to include an optional visit to the vicinity of the chough release aviary at Sorel in the afternoon of Day 2. This visit may, however, be dependent on the autumn weather (think Jersey in October) and chough activity!
To help you now with your planning, the meeting will:
• Start on Thursday 9th October at 10am (preceded by coffee/registration from 9am) • Timings for the first day will be 10am – 6pm. Lunch: 1-30pm – 3pm. Refreshment breaks in morning & afternoon • Timings for the second day will be 9am – 4pm. Lunch 12-30pm – 2pm. Refreshment breaks in morning & afternoon • There will be optional dinner out on Thursday evening (venue TBA) and an optional bar meal on Friday evening (venue TBA)
A small charge will be levied on all delegates to cover refreshments and lunches for Thursday and Friday (please let the organisers know in advance of any special dietary requirements). The charge is anticipated to be £25 per person for two days and will be collected at registration. Payment of the full fee will entitle the paying delegate to entry to the Durrell Wildlife Park.
If you are interested in attending or would like further details please contact Glyn Young glyn.young@durrell.org, the Conference Organiser, as soon as possible.
The organisers look forward to hearing from you and to sharing what they hope will be an enjoyable and thought-provoking Inter-Island Environment Meeting!
Details of previous Inter-Island meetings can be seen here: 2012 and 2013.
As reported last month, Durrell has been artificially incubating chough eggs this year. On 30th April our first egg hatched. Closely followed by a second then three more within a week. These eggs were from the first clutches of two different pairs.
Recently hatched chicks are housed in a heated brooder. Photo by Liz Corry
It is always a worrying time waiting for an egg to hatch. It can take over 24 hours for a chough to hatch out of its shell and ours certainly were not in a rush. If a chick is strong and healthy it has no problems hatching. Occasionally, however, a chick is too weak and struggles. We encountered this in two of our eggs, the chicks began external pipping (chipping away at the egg shell) but were sadly too weak to break out and died in the shell.
The five chicks which did successfully hatch were still not in the clear. As mentioned in last month’s report one of these chicks had complications with a protruding yolk-sac and died within a few days. The other four did much better and grew bigger each day. Quite an achievement considering staff had never hand-reared a chough before and rearing from the egg stage is always the hardest.
Chicks kept in a ceramic dish lined with paper towel to create nesting environment. Photo by Liz Corry
The hand-rearing protocol used was based on our previous experience with rearing passerines. We also looked to Paradise Park for information, as they have tried artificial incubating and hand-rearing choughs in the past, as well as to other global institutions who have corvid experience.
We fed the chicks a diet of finely chopped mice and papaya with insects added from day 3. To start with they were fed every hour from 6am until 11pm. As they get older their energy demands change and they only need feeding every 90 minutes or two hours. We also cut back on the duration of feeds so that by the time they were a few weeks old they were fed from 7am until 7pm.
Chough chicks at around ten days old. Photo by Liz Corry
When we feed them we play back recordings of wild chicks begging, the noise the female makes at the nest when arriving with food and, in between feeds, we play adult flight calls. This helps the chicks to associate with chough voices and not the human ones around them. To aid this we also minimised the amount of human contact time and stopped taking them home in the evenings. At Durrell we usually take the hand-reared birds home with us to avoid making several trips back to the office at night and at 6am in the morning. This stops when the chicks are about to fledge. It becomes too hazardous to drive them home having them hop around in the brooder. For the choughs we stopped once their eyes started opening. This particular species is prone to imprinting and for the reintroduction project it is imperative that they don’t imprint on the wrong thing.
Chough chicks at twenty days old. Photo by Liz Corry
For this reason we also wore a black glove and used red tweezers when hand feeding the chicks. This presented the chick with the rough image of a parent’s head and not a human hand. We want the chicks to have a certain level of tameness for the release process, but we don’t want them taking food from a tourist’s hand. It seemed to do the trick. They never stopped eating anyway. Chicks were weighed daily and, on comparison with wild chick data, by the end of May they were exceeding all standards.
Double-clutching efforts 2014
Chough chicks being hand fed with tweezers. Photo by Liz Corry
Whilst we did show that choughs can produce a second clutch if the conditions are correct, we failed to glean anything of use from those clutches.
As mentioned last month there were problems with parents discarding eggs and the loss (escape) of Arthur disrupted Issy’s attempts. We managed to rescue three eggs to set in our incubator. Unfortunately these suffered from the same problems as the last clutches. Insufficient weight loss leading to embryonic deaths. Hopefully, we can look back through the data collected this year and work out improved incubation protocols for next year.
Summary of hand-rearing programme
Chicks at four weeks old start being a bit more mobile and no longer fit in the brooder. Photo by Liz Corry
Statistically a 33% success rate from 13 eggs is not a great achievement and there are definitely areas for improvement. However, it is still an incredible accomplishment to have hand-reared four chicks from eggs all taken before parental incubation had really begun. It takes a lot of commitment and emotional investment on behalf of the keepers. A lot has been learnt that will not only benefit the chough breeding programme but the other species hand-reared at Durrell too.
Chough chicks take about 6-7 weeks before they leave the nest. Normally the keepers are used to seeing their hand-reared chicks fly within three weeks. This is double the effort and double the wait to see if these four chicks successfully fledge into well adapted juveniles fit for release into Jersey.
Health screening and DNAsexing
Chicks being taken to the Durrell Vet Department for routine health screens. Photo by Liz Corry
Chough chicks are hard to sex visually. It is based on bone measurements and body weights although individuals can vary. Common practice in captivity is to take a pin-prick of blood dotted on blotting paper and send it off for DNA analysis. All four chicks had samples taken and we will await to hear the results in June.
They had their first visit to the vets this month. All routine. We screen faecal and blood samples for various parasites and bacteria whilst the birds are held at Durrell. We will screen again once they are out at Sorel. It allows us to make comparisons and highlight any concerns which may require treatment to increase their chances of survival.
Whilst in the hand, each chick was implanted with a transponder. This has a unique code which allows individuals to be identified if rings are lost or maliciously removed as can be the case in the pet trade. The chicks didn’t seem too phased by their visit as they were eating as soon as they went back to their housing.
Sorel soft-release update
April saw the start of the 2014 soft-release for eight choughs up at Sorel. Very quickly eight became six with the mysterious disappearance of Yellow and Cerise after the first week (see April’s report).
After a week or so of opening and closing hatches each day, Red and the young male White grew in confidence and decided to join the others when they flew out of the hatches.
By May the six had started to fly as a group, feed as a group, and play in the quarry buildings as a group. But, when it came to returning to the aviary they still had their own ideas. Sometimes they would fly back in twos or threes. We could, with relative ease, shut them in to the back sections and reopen hatches waiting for the remainder to return.
When they returned as a group of six it often made it impossible to shut the hatches. There might be at least one bird on the roof on lookout whilst the others fed inside. Any movement like a passing cyclist or friendly team member approaching the hatches and an alarm call would send the group fleeing.
We also encountered the same problem as last year with the pair, Green and Mauve, who don’t like being shut in. They would bolt at the first sign of a keeper. Unless of course they were really hungry in which case their motivation to be outside was overruled by their stomachs. On the odd occasion of one of them being shut in, the other would hang around the aviary begging to be let in with them.
It was quickly becoming apparent that not all of the choughs liked being shut in. We did not want them to start viewing the aviary as a negative experience. The soft-release method had to be adapted. Instead of locking them in as they returned we waited until roost. At this point if the birds were in the aviary they were already fed, settled, and hopefully asleep and oblivious to the keepers. Hatches were reopened the next day and the timing brought forward by 30-60 minutes each day. So eventually the birds were being released at 8am then locked in again at 9pm.
It meant that the team faced a long day spending the last hour before roost accounting for all six birds, then lurking in gorse bushes or hedgerows while waiting until sunset. On a couple of occasions the radio signals indicated that all six were at the aviary, but due to fading light and roost boxes it wasn’t obvious to see exactly where they were. We would not know until sunrise. Twice we found a bird had spent the night in the external roost box on the side of the aviary.
On one or two occasions Mauve would roost in the quarry whilst her partner chose to roost in the aviary with the others. She would reappear at the aviary in the morning for breakfast.
By the end of May the birds had clearly settled into a routine and were adapting well to life outside the aviary. The hatches were finally left open so the birds could come and go as they pleased.
Radio-tracking sessions started to blur into feeding sessions as the birds quickly learnt what time of day to expect staff to be at the aviary. At the first visit at 7:30am you might find them probing the ground by the edge of the cliff path, but as soon as they catch site of you or hear the gate opening they take to the air calling and fly to the aviary. It would also happen during the day, providing they were hungry enough. This time of year there are plenty of insects around to keep them occupied. As well as other distractions/attractions (depending on your view) at Sorel this time of year.
Dispersal range of released choughs
With the exception of the missing birds, the released choughs have not ranged far from their release site. We know choughs can fly far if they feel the need to. Yet during the breeding season they tend to stick within a few hundred metres of their nest site. Our choughs are not exactly in a normal situation though. What is more they are entering into an environment with no other choughs for guidance (or competition) and a habitat that still needs improving.
Last year they quickly turned the quarry into their second home and would venture no further. In fact they didn’t really spend much time elsewhere except the aviary. The only ground they touched in between was Sorel Point.
In April it looked like it was going to be much the same. As the group cohesion outside the aviary strengthened and the birds became more confident it quickly changed. By May they were foraging the grazed land next to the aviary. Probing for insects in amongst the flock of sheep.
Choughs started exploring Crabbé in May but after several exploratory flights decided to stick with Sorel. Photo by Liz Corry
After a week or so of exploring this area they decided to take it up a gear. During the phase of releases when hatches were opened around 10:30 and closed at sunset the group spent a few days visiting Crabbé.
Like clockwork they would fly west when the hatches opened. At first just circling the valley before heading to 2km west then soon straight to their destination. By the time the radio-trackers had jumped in the car and driven round the group would be back at Sorel.
We pre-empted them one day by splitting up and stationing one person at Crabbé before the hatches opened. Sure enough they flew over and continued over the shooting range out of site. Very quickly they returned, flew around Île Agois, then back to the aviary. They did this three times within 60 minutes and never landed at Crabbé.
These were exploratory flights which obviously told them they were better off staying at Sorel as they soon stopped going. This could be for very several reasons. Firstly the raven chicks had just fledged. They don’t pose a threat to the choughs but the parents definitely didn’t want the extra company in ‘their’ air space. A more likely threat would come from the nearby peregrine parents with their newly hatched, hungry chicks. Gunshot from inside Crabbé’s shooting range didn’t scare the choughs but guaranteed they weren’t going to land on the sand bank and grassy areas. The big drawback would be current habitat. A lot of agricultural fields, bracken and other overgrown vegetation are not what the choughs are looking for. There is a small area of short grass around the cliff path approach, but at the time of the chough visits there were hikers and farm vehicles that would deter a first time chough visitor from landing.
What is interesting is their lack of desire to explore the Devil’s Hole side of the valley where the sheep roam. They can see the land from the aviary, but as far as the team know the birds have never touched down over there. Maybe in time when they deplete their insect supply at Sorel.
The choughs also seem to avoid exploring the rocky cliffs on foot and the lower grazed areas that slope down into the sea. Again this might be something that comes with time. For now they seem happy around the aviary. Free board and lodgings. Why look anywhere else?
Training finally pays off
When people hear about how the releases have ‘skewed’ off plan they are quick to assume that the behavioural training has not worked. A bird is a bird; it will do its own thing. In some respects this is true. They haven’t always returned to the aviary when the whistle was blown for dinner but it may not be because they don’t know what the whistle means. There are many reasons why they don’t return and each bird has its own reason.
Evidence that the training has worked came to light once the birds gained confidence and started settling into a routine of returning to the aviary at night.
The choughs are now frequently flying up from the surrounding cliff top when they hear the whistle and heading straight to the aviary. They then land on the target boards where the keeper has left the food. If the food is left inside the aviary they can be cautious and wait patiently on the netting above until the keeper has left. They feel less restricted when the food is left outside and can fly within inches of the keeper’s head following them from target to target.
This has also meant we can continue to record body weights when they land on the scales in just the same ways as when they were locked in the aviary.
An interesting indirect pay-off of the training this year has been evident when they have encountered peregrines. The peregrine nesting season has probably meant there have been fewer interactions with the choughs compared to August and September last year. When a peregrine has flown along the cliff path the choughs take to the air and return to the aviary. They have obviously learnt to associate the aviary not just with food but with safe shelter.
Annual moult
The odd feather seemed to be appearing here and there on the ground at the release site. With all six accounted for and looking happy and healthy it could only really mean one thing. They’d started moulting. A couple of weeks later than last year but nevertheless the countdown had begun. By next month it is likely they will have moulted their tail feathers and dropped their radio transmitters.
UFO sightings over Jersey
We had a report of an unidentified flying object at Mont Orgueil Castle on the 6th. Chris Durbano a site guardian for the castle emailed Birds On The Edge to say he spent Saturday watching what he thought to be a chough feeding around the grounds of the castle. The bird disappeared as the numbers of visitors picked up during the day, but reappeared at closing time. Chris was able to take a photo clearly showing a chough stood on the ramparts of the castle. We suspect from the rings that it was Arthur our breeding male that escaped from the wildlife park on 30th April.
We visited the castle as soon as we read the message, but with the sighting being three days previous he (Arthur) had had a chance to move on. A few days after, we received a call about a chough sighted in a garden at Les Platons. The description of the bird and its behaviour makes it likely that it was indeed a chough. The team were in the area within thirty minutes of the sighting, but there was no site or sound of a chough.
It is more than likely that after being in Gorey, Arthur made his way round the coastline looking for suitable feeding grounds and a safe roost spot. It would be ideal if he made it all the way round to Sorel or back inland to the Wildlife Park. This has yet to happen and we can only hope that he finds sufficient resources to continue his journey.
A plea was made to the Jersey public and colleagues on the neighbouring islands and France were alerted to Arthur’s escape and the missing released pair (see report here). We received a handful of reports none of which resulted in finding them. We are still asking the public to report sightings of choughs via email or by phoning Durrell directly. As more and more choughs are released we will become even more reliant on the help of the public. It might be a small island but the choughs have one advantage over us….they can fly!
Landscaping at the aviary
Strimming round the aviary. May 2014. Photo by Liz Corry
A big thank you to Johnnie McLaughlin, Ecoscape, and Sally Dalman and the National Trust for volunteering to cut the grass and weeds around the aviary. The hedgerows are once again overgrown with bracken and weeds. It has created a haven for rodents especially rats and has been creeping closer to the aviary. Something has been having a go at the aviary netting and we need to deter them. The short grass should also create a better environment for insects, especially ants, which the choughs love to eat.
The National Trust for Jersey is delighted to announce that peregrine falcon chicks were ringed at a nest site for the first time in Jersey since the species became locally extinct in the late 1950s.
The breeding site, on a stretch of Trust land on the north coast, has been monitored by a team of local ornithologists for the last few weeks. The chicks have been fitted with individually marked rings for future identification during an operation where other data were collected including biological measurements of the birds and prey remains in the nest.
The peregrine falcon, a top predator of the skies once common on every continent except Antarctica, almost became extinct in the second half of the 20th century due to persecution and the use of pesticides that caused a fatal thinning of their eggs’ shell (see e.g. here). The disappearance of peregrines on the coastal cliffs of Jersey in 1958 was likely caused by the same reasons.
Thankfully, bans of the pesticides such as DDT and legal protection awarded to the species have allowed it to recover worldwide and eventually make a comeback to Jersey, where a new breeding pair was found in the year 2000. Since then, other pairs have settled on the cliffs of the north and south-west coasts and even in St Helier.
This year the Island population stands at seven pairs of falcons (there is a survey of peregrines in the UK, Isle of Man and the Channel Islands this year), of which five are found on the north coast (two of them on Trust land and two others at Sites of Special Interest). The peregrine has been given Amber status of conservation locally which reflects the small yet seemingly stable population (see full list here). So far this year only five out of the seven pairs have bred successfully, having raised 2-3 chicks each, which have already fledged. Up until now only fledglings that got themselves into trouble and had to be rescued had been fitted with the metal rings, this the first time since peregrines returned that a team of experts has been able to monitor a nest and ring the chicks.
The information from bird-ringing projects like this helps scientists and conservationists to learn about issues such as migration, lifespan and breeding ecology (see e.g. Sussex Peregrine Study). It is hoped that in the future more chicks will be fitted with the same rings and help us further our knowledge of this species’ ecology in Jersey.
The presence of peregrines at a certain area indicates a dynamic food chain and a healthy natural community. The National Trust undertakes active management on its land on the north coast and sees the success of this species as a sign of the recovery of the coastal habitats. It is hoped that we will be able to enjoy the sight of a peregrine falcon cruising the cliffs for many generations to come.
Islanders with an interest in helping to protect Jersey’s bats are invited to a workshop at the Durrell Conservation Academy on 5th July organised by the Department of the Environment and the Jersey Bat Group.
The workshop, which includes talks and training, will help people learn how to survey bat roosts in local buildings to record and learn more about where they roost.
Jersey is lucky enough to have more than 11 recorded species of bats. The most commonly found bat species is the common pipistrelle, but the Island also has long eared bats and serotines.
Volunteers from the Jersey Bat Group and the Department of the Environment record information on bats by making ‘exit counts’ – watching and counting bats as they leave their roost around dusk. Where possible, they identify species using special equipment that translates the ultrasonic calls that bats make into sounds a human ear can hear.
Volunteers are trying to visit roosts that have been recorded in the past to see if the bats are still using them, and are also keen to find new roosts not currently on record. They want to hear from people who think they may have bats on their property. Signs include:
tiny droppings on window ledges or stuck on the side of walls
bats seen emerging from gaps in the property such as from under ridge tiles, or from under fascia boards
clear, cobweb-free gaps under fascia boards.
It’s an important time of year for bats as females will have recently gathered in their ‘maternity roost’ to have their single ‘pup’. They are usually loyal to old successful roost sites, often for generations.
Chair of the Jersey Bat group Nicky Brown said, “Bats are an amazing and vital part of our wildlife, providing a valuable service to our environment; a single pipistrelle can eat 3000 mosquitoes or midges a night.
“But if we’re to continue to conserve the many different species we’re home to, it’s crucial that we continue to monitor their population and raise awareness of their needs. For that, we really do rely on the good will and knowledge of volunteers. If you think you might be interested in knowing more, or helping us with our summer surveys please sign up for the training day, and consider joining the Jersey Bat Group.”
The workshop is open to anyone interested in learning more about bats and who want to get involved helping with the summer surveys. It is being held at Durrell Conservation Academy on 5th July between 2 pm and 8 pm. If you would like to attend, please reserve a place by contacting Nina Cornish on 441624 or by email: n.cornish@gov.je.
If you think you may have bats on your property, or you would like more information on the bat group or the summer surveys please contact Nicky Brown at jerseybatgroup@yahoo.co.uk or David Tipping at d.tipping@gov.je or on 441623.
To guide island-based seabird conservation actions, a new review has been published in Conservation Biology. The paper identifies, for the first time ever, every single island and islet worldwide where globally threatened seabirds breed, as well as whether invasive alien species are present and threatening them.
Seabirds are some of the most threatened marine animals in the world, with 29% of species at risk of extinction. Significant threats to seabirds occur on islands, which is where seabirds breed, including predation and disturbance from invasive alien species such as rats, cats and pigs. However, in many cases, effective island conservation can mitigate these threats.
’Thanks to hundreds of collaborations from seabird biologists around the world, we were able to compile a global database that identifies islands where threatened seabirds are vulnerable to extinction. The Threatened Island Biodiversity database also highlights islands where invasive species eradications are needed or where protected areas are missing”, said Dena R. Spatz, lead author of the paper.
The Biogeography of Globally Threatened Seabirds and Island Conservation Opportunities, written by scientists from the Coastal Conservation Action Lab at the University of California, Island Conservation, and BirdLife International, identified all islands where populations of the 98 globally threatened seabird species (as classified by BirdLife International on the IUCN Red List) now remain, and documented the presence of threatening invasive species, protected areas, and human populations. This list was then refined to identify islands that have the greatest opportunity for interventions to benefit threatened seabirds. It will now form the basis of further priority-setting to determine where action is most urgently needed.
“This information is critical to guiding where to prevent threatened seabird extinctions, and is a rare opportunity for effective conservation at scale,” said Nick Holmes, Director of Science, Island Conservation.
“Invasive alien species like rats cause significant economic damage and harm to people too, but on islands it is often feasible to eradicate invasive species, benefiting local communities as well as native wildlife,” added coauthor Dr. Stuart Butchart, Head of Science at BirdLife International.
Highlighs
Over 1300 present and locally extinct seabird populations (representing 98 species) were identified on 968 islands;
Invasive species – a major threat to seabirds – potentially impact breeding populations on 60% of these islands;
Only one third of threatened seabird islands (359 islands; or 37%) are formally protected (i.e. >90% covered in protected areas), and over half (534 islands; or 55%) have no legal protection. 83% of threatened seabird islands lack adequate protection and/or are threatened by invasive alien species;
Eradicating invasive mammal populations to benefit native species is a tried and tested conservation technique. Most islands with threatened seabirds can easily be saved from these threats because the islands are small (57% were <1 km2), uninhabited (74%), and are owned by relatively wealthy countries (96% owned by higher income countries). Collectively these attributes make islands with threatened seabirds a rare opportunity for effective conservation at scale.
No Channel Islands seabirds are globally threatened although possibly all are now locally threatened with extinction. This new review is, however, invaluable to local conservationists as many of our former and potential breeding sites are home to invasive species (notably rats and cats) and all need protection and restoration if we want to see seabirds in our waters in years to come. Birds On The Edge has reported on several projects around the British Isles aimed to restore locally threatened seabirds which might be appropriate in our islands (see Ramsey, Scilly and Calf of Man).
By Liz Corry
By Cris Sellarés
