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).
Local ornithologists are investigating the possibility that Manx shearwaters may be trying to breed near Plémont, after a recent survey suggested once again that some of these birds might have been prospecting the area for nesting opportunities.
Manx shearwaters are shy, burrowing seabirds related to fulmars, petrels and albatrosses that spend most of their life at sea and only land to dig a burrow where they will lay a single white egg. Like that other burrowing seabird the puffin, shearwaters are susceptible to human disturbance and predation by introduced mammals such as rats, cats and dogs. In areas where these predators are found the seabirds favour coastal cliffs that are difficult to access. Even then, they will only visit their nests during the darkest nights, to avoid predation by gulls and other birds.
Their name comes from the Isle of Man, where once a large colony was found on the Calf of Man. The species became extinct there after a shipwreck in the 18th century accidentally introduced rats onto the island. Rat eradication projects have succeeded in restoring the breeding colonies of this seabird not only on Calf of Man but also on Lundy (where the population has grown from 166 pairs in 2001 to over 1,000 in 2008), the Isles of Scilly and Ramsey Island (where its population grew from 850 pairs in 1998 to over 3,800 in 2012).
In the Channel Islands small numbers of Manx shearwaters have, in recent years, nested in Sark and Jethou, although no surveys have been undertaken recently. The closest colonies are in the Isles of Scilly and Brittany. In Jersey, small numbers have been recorded in the vicinity of Plémont almost every summer at the height of the breeding season. Unfortunately it is unclear whether they have actually nested here or are merely non-breeding individuals visiting the area looking for a potential future nest site.
This year’s survey detected more shearwaters (four were over the land after dark) in the area than in any previous years, and local biologists are eager to find out if the species is breeding in Jersey. Further surveys are planned for the next few weeks.
Whilst the birds may not be breeding this year, they might be prospecting the area for a suitable nesting site, and their presence is an encouraging sign. If shearwaters were to establish a small breeding colony in the Jersey it would greatly enhance the ecological value of our coastline and maintain seabird diversity of the Channel Islands. Pairs from this species form life-long monogamous bonds and can live for over 50 years, so it is hoped that a breeding colony would have a long and safe future in the coastal cliffs. Any possible restoration projects at Plémont like those mentioned above aimed to encourage nesting by shearwaters could only be beneficial to puffins as well.
The avid reader amongst you will have noticed a delay in monthly reports of late. There are two very worthy reasons for this. The first is the extraordinary busy schedules of the breeding season and the release project. The second is the sensitivity surrounding both those areas. However, I am now pleased to be able to report on the highs and the lows of April and it was well worth the wait!
Breeding season begins at Durrell
A decision was made at the start of the season to hand-rear the first clutch of eggs from each pair and try double clutching. The parents would then be allowed to rear the second batch. Hopefully we would increase productivity and have a mixture of hand-reared and parent-reared chicks to release into Jersey. Each group would share their knowledge with the other, thus avoiding imprinting in the hand-reareds and making the parent-reareds more willing to co-operate with training.
The first chough egg of the season was laid on 6th April. Nest-cameras had been setup in all three breeding aviaries so keepers could closely monitor progress. And boy did it pay off!
Down in Shep’s Field we had Gwinny with her inexperienced male (Mauve) in SF3 aviary and Tristan with our inexperienced female, Black, in SF2 aviary.
Gwinny’s nest with an egg before the male removed them. Photo by Liz Corry
Despite Gwinny being the first female to start nest building she was the last to lay. In fact she did so only after the others had already laid their clutches. On the 25th keepers noticed that there was an egg in her nest and a second on the 26th. Then suddenly nothing!
Searching back through the recorded footage an interesting relationship unfolded. Bearing in mind these two birds did not choose each other as the other pairs did it was quite warming to observe the male feed Gwinny in the nest.
Closer observations, however, showed a very inquisitive, slightly confused, male. With an egg in the nest, the male would often stand on the edge of the nest peering at it. Gwinny would come back, chatter at him and display until he left the nest. On the morning of the 26th the male edged further into the undefended nest, moved a few twigs, and then carefully removed an egg.
Gwinny laying an egg whilst the male watches with interest. Photo by Liz Corry
He repeated the behaviour an hour later leaving behind an empty nest and a very disheartened female.
In SF2 things were looking more promising. A nest had been built and an egg was laid on the 6th around 23.00. The video showed an exhausted female panting and pushing out the egg, resting in the nest until dawn and then leaving to find food. When she returned three hours later she looked in the nest and spotted the egg. Having never seen an egg before, and maybe not realising that is what she had been pushing out (?), she decided it shouldn’t be in her nest and carefully removed it.
Black removing her first egg from the nest. Photo by Liz Corry
A decision by staff was made to swap the next egg she laid for a dummy egg and artificially incubate the next egg. For some reason the male took offense to the dummy egg and removed it in the evening. In total the female laid five eggs, but with one already destroyed, only four were taken to Durrell’s Bird Department for artificial incubation.
Black was only left with the dummy eggs for a couple of days after the last egg was laid. They were removed by keepers to encourage the pair to double-clutch. They did! On the 26thBlack laid an egg in the morning, but once again destroyed it by the evening. A second egg appeared on the 29th and was taken for artificial incubation. Egg-laying stopped.
Tristan and his female Black fighting in nest-box. Photo by Liz Corry
Without looking back through the footage keepers would never have known that on at least two occasions in the nest-box the pair had been physically fighting. This implies that despite choosing each other as mates there is something amiss. It might just be her inexperience and a second season may be needed before the pair can become harmonious.
The third pair, both established breeders, housed in the display aviary starting laying on 6th April as well. The camera in here is linked straight to a monitor and not recorded so information is based on keepers’ periodic observations. This pair followed the plan of laying a clutch of five eggs which could then be exchanged for dummy eggs after a period of parental incubation. From observations it appeared that Issy (female) did not really sit tight on the eggs when it came time (they incubate from third or fourth egg). When keepers’ observed from outside of the aviary she would leave the nest every time the public went past. This problem needs to be addressed by next season.
Issy also went on to produce a second set of eggs two weeks after the dummy eggs were taken away. Unfortunately, for some reason she did not take to these eggs. The first was kicked out, the next two were taken for artificial incubation, but she kicked out the dummy eggs. There was an additional problem. Two days after the first egg of the second clutch was laid Arthur (her mate) escaped. He was seen in the morning on the other side of the netting. Presumably he left through one of the holes in the netting. These cannot be fixed by staff without scaffolding or a cherry picker and during the breeding season neither can be used.
Arthur paid a visit to the other choughs down in Shep’s Field before flying over the Orang-utan House and out of sight by 10:30. Appeals to the public resulted in a positive sighting at Gorey Castle four days later and then two days later at Les Platons. There have been a handful of reports since but all describing blackbirds or (we think) in one case a jay. We have tried to follow up as many as possible. In reality it will be very hard to recapture Arthur unless he is weak or injured. If he is located and remains in that area it might be possible to supplementarily feed him and later, if the situation allows, trap him. For now we have to hope that Arthur has the means to survive and may well be the first breeding chough to live in Jersey.
Artificial incubation of chough eggs
Four of the eggs set in the incubator. Photo by Liz Corry
In 2012 Durrell attempted to incubate two eggs from an abandoned nest. These unfortunately failed early on. So you can imagine how nervous keepers were this time round with nine eggs to incubate followed by another three from the second clutches. With advice from Paradise Park, who have achieved success in the past, and using our existing knowledge with other species we managed to hatch five eggs. A lot has been learnt from the experience and will be used next season to increase this success rate.
All eggs were weighed and candled on a daily basis to monitor development. Egg weight-loss graphs were plotted so incubation parameters could be altered in accordance to development. Eggs such as these are expected to lose 15% of their original weight by the time of hatch.
Eggs are candled and weighed daily to monitor development. Photo by Liz Corry
Our eggs all appeared too wet and were not losing enough weight so humidity was reduced dramatically. For some eggs it was too late or made no difference. Some embryos died early on, two eggs reached the chipping stage but died before hatching. One chick hatched but had developed an abnormality with its yolk-sac which led very swiftly to death.
Post mortems were carried out on eggs and chick to try and underpin the cause(s). No evidence of bacterial infections was found. Most signs pointed to failings with the environmental conditions in the egg.
The first egg hatched on 30th April with the second close behind. Photo by Liz Corry
For those eggs that were successful in hatching there will be more to read in May’s report. Not simply to keep you hanging on bated breath, but because the first egg only hatched on 30th April.
First release of 2014
The choughs at Sorel have spent the last few months riding out the winter gales in the aviary. All hatches firmly battened down. With conditions favourable and all health checks passed it was time to restart the releases. On 9th April the hatches were opened and the birds allowed to fly free. The intention was to give them thirty minutes of playtime before calling them back in for food. What happened in those thirty minutes was exhilarating, poetic, and simply nerve-wracking for both chough and their team.
The group of eight choughs took to the air, rising higher and higher, swooping left, swooping right. Sometimes in a 3, 3, 2 formation, at others a 2, 2, 4, and 5, 1, 2. It was like watching a red arrows display only without the trailing smoke (in discussion for next year’s releases). All the time they stayed around the neighbouring fields, never really crossing over Mourier Valley, never out of sight to the east and only two or three fields inland. Bearing in mind at the height they were reaching they would be able to see Jersey in its entirety.
Day 1 of the 2014 release and the choughs fly higher than ever before (look for two black dots to the left of the vapour trail). Photo by Liz Corry
As the stop-clock ticked down and their keeper was about to call them back for dinner, the inevitable happened. They headed for the quarry. Interestingly when the keeper blew the whistle one bird, Red, headed back to the aviary. She did the same thing last year after her original mate died in the quarry. She has the desire to explore, but maybe it is overcome by her knowledge of easy food and protection at the aviary.
Red obediently returning to the aviary. Photo by Liz Corry
We had thought she would stick with her new partner, Yellow, the older male who arrived in December. With hindsight and all the ingredients of your favourite soap opera we should have realised otherwise. Whilst in the aviary Yellow had been seen courting Red and they would often feed and roost together. As hormones kicked in for the breeding season Yellow started making advances on Mauve. Mauve’s partner, Green, naturally objected to this and on a few occasions the team had witnessed fights between the two males. Red, whilst still keen on Yellow, was starting to get the cold shoulder.
Yellow, the oldest in the group, before he disappeared on Day 1 of release. Photo by Liz Corry
It is hard to tell who is who when they are flying high above your heads, but we know that Yellow parted ways after the thirty-minute mark on the first day of release. When the others flew to the quarry, Yellow headed inland. Rather naively we thought he was heading the long way round to the quarry, but after a relatively short time of radio tracking to account for the other six birds we had lost his signal completely. Not only had he ditched Red but the entire group. We expected from previous behaviour that the two older males would not want to hang out together given the choice, but we didn’t expect a new arrival to leave the entire group.
To further add to the confusion only five choughs were visible in the quarry yet six signals were being picked up. After many questions, equipment testing, and stroking of chins it became clear that the sixth signal was not a true signal. Instead it was a combination of electrical interference (e.g. electric fences surrounding horse paddocks) and picking up the tail-end of another bird’s frequency. Much like when you tune in a transistor radio and can hear two stations competing. This missing bird was Cerise a 2013 female brought to Jersey in December. We think she might have followed Yellow.
By the end of the first day there was one chough in the aviary, five roosting in the quarry, and two missing. It is worth noting that the birds in the quarry visited the exact same sites as they did last year and did not deviate. They returned to the aviary over the course of the next two days and were locked back inside as they arrived. Releases were put on hold until we had a better idea of where the missing birds were.
The new students Pierre and Adam were put to the test straight away. The team covered many miles on foot and even more by car in an attempt to radio search the island in a short a time as possible. After two days of hearing nothing but white noise it was an tremendous feeling to be able to hear the beep beep of a transmitter signal once again.
It was Yellow’s signal, detected at Noirmont Point but coming from the St Aubin side. This is an area 9.5km south of the release site. In fact it is quite close to the last reported breeding site for choughs back at the start of the 20th Century. The cliffs to the west of the point seem favourable for a roosting chough and Noirmont has a large area of suitable feeding ground. However, these days it is a popular tourist and recreational area so disturbance is frequent. What didn’t quite fit was the exact location of the transmitter; low sandy cliffs and a forested area above them. Visual searches were hampered by the tides and when access was finally gained the signal had disappeared. No sight or sound of Yellow has been detected since. Nothing at all has been heard from Cerise.
Within the first few days of their disappearance two other search methods were adopted based on previous studies. Lee Durrell kindly allowed the use of her plane piloted by Colin Stevenson. Whilst the choughs in the aviary could be detected from the air no other signals were picked up. This method has its flaws. It is very dependent on the bird being out in the open. It is also easy to miss something as you can’t tell the pilot to “stop, back up, I think I heard something”.
A search from the sea was also attempted. Peter Haworth of New Era Vets loaned his boat and services to search the north coast. Signals from the Sorel choughs could be detected, but no others. Time constraints meant that further boat searches have not been attempted.
The releases of the six remaining choughs continued on 15th April. At first the birds were behaving as individuals. The pair Green and Mauve would fly off to the quarry in search of the buildings. The lone females, Black, Blue, and Red would follow but head to the grassy areas in the quarry. They would return to the aviary but often Black and Blue would look to Green and Mauve for guidance as to when to do this. White, the 2013 male brought over in December, did the opposite.
For the first week of releases White wouldn’t leave. Photo by Liz Corry
His behaviour was typical of a scared bird that wanted to be with other choughs but didn’t want to leave the security if the aviary. His first day of release on the 9th saw him return in the evening to the cliffs by the aviary. He spotted the team but was too anxious to take food and went back to the quarry to roost with the others. He returned the next morning and went straight into the aviary. For the next week or so any time the hatches were opened he would fly to them with the others but never actually leave. He would fly straight back to the other end and call loudly. Almost as if he was shouting “Where are you going? Why can’t we just stay here where the food is? I don’t like wide open spaces. Come back”.
White searching for the others at sunset on Day 1 of release. Photo by Liz Corry
Finally he caved-in to the pressure of being left alone each day and joined the group. By this point the other five had started flying and feeding together. The team found it difficult sticking to their original plan of calling birds back and locking them in as they arrived. For starters this meant waiting around all hours from dawn until dusk. We were also faced with the intelligence of the pair. Whilst they knew that returning to the aviary meant food, it also meant they would be locked in and their freedom to roam the quarry restricted. At the first sign of one of us approaching the aviary they would bolt straight out and off to the quarry. Unless they were desperately hungry or one had been caught and the other wanted to be with it. April was a hectic time for all involved. Yet all signs were positive that the release process was heading in the right direction and choughs were once again flying free in Jersey.
A new study has found that anthropogenic electromagnetic noise, emitted everywhere that we use electronic devices, has a negative impact on birds’ magnetic compasses. The work, which used robins as a study species at the University of Oldenburg, found that the birds could not use their compass when exposed to electromagnetic noise but, when shielded from it, soon regained their navigational abilities. The ‘noise’ is produced by equipment plugged into mains electricity supplies and through AM radio signals.
Prof Henrik Mouritsen (University of Oldenburg) said “They (birds) have their different compasses: a star compass, a sun compass and a magnetic compass”. It is thought that a built-in magnetic compass, which senses the Earth’s magnetic field, helps them to find their way. Prof Mouritsen told BBC News he stumbled across the fact that low frequency waves could be interfering with this by accident while studying European robins.
“The basic experiment we do in bird navigation research is that we put birds into an orientation cage,” he explained. “They are so eager to migrate, that they will jump in the direction in which they want to fly, and if you turn a static magnetic field in the horizontal plane they will start to jump in a different direction.
“That experiment has worked for more than 40 years in a number of locations. But here in Oldenburg, we couldn’t get that basic experiment to work until one day we got the idea to screen these huts on the inside with aluminium plates so the electromagnetic noise was reduced about 100 times.
“And suddenly the birds started to orientate.”
Over the course of the next seven years, he and his team carried out numerous experiments to look at how the weak electromagnetic field affected the behaviour of the robins. In essence, he found that birds exposed to electromagnetic “noise” between 50 kHz and 5 MHz lost all sense of direction. But when the field was blocked out, they found their bearings again.
Prof Mouritsen said that migratory birds flying over towns and cities, where there are more homes and businesses that use electrical devices, would be most affected – and they would probably resort to back-up navigational systems.
“The birds wouldn’t be completely lost because they have three different compasses: a star compass, a sun compass and a magnetic compass, and they work independently of each other. As long as it is clear they should be fine with their sun compass or star compass.”
These findings are particularly fascinating when considering the vagrancy of migratory birds. While the impact of electromagnetic noise is unlikely to be a primary cause of vagrancy, its potential to disrupt migrating birds — whether lost or following a more typical path — is evident if and when they pass through populated areas, where use of electronic devices is high, and there can be no doubt of its potential as a contributing factor. Further study on other migratory species would be useful in establishing the true extent of such problems.
Fishing vessels have a far bigger ecological footprint than previously thought, according to research which tracked the movement and behaviour of seabirds using GPS devices.
Scientists discovered that northern gannets change their behaviour in response to the presence of large vessels such as trawlers, suggesting each boat can significantly influence the distribution and foraging patterns of these and other marine predators.
Northern gannets are known to feed on discards from fishing vessels as well as diving for fish, and their population has been steadily increasing for decades. Studies have confirmed their use of fisheries waste by showing that the birds are eating fish that have come from far deeper than they are able to dive.
Scientists at the Centre for Ecology and Conservation at the University of Exeter and the Coastal & Marine Centre at University College Cork analysed GPS tracking data from 74 gannets from six breeding colonies around Ireland, and combined these with similar GPS tracking data from fishing vessels.
The information gathered revealed that gannet behaviour is influenced by fishing vessels at distances of up to 11km – the first estimate of the distance at which vessels start to affect these birds’ behaviour.
Dr Thomas Bodey of the University of Exeter, who led the study, said: “Our work suggests each fishing vessel has a substantial footprint, with the behaviour of seabirds affected within a 22km diameter circle surrounding it, much larger than we expected.”
By studying bird-boat interactions, the team also discovered that individual gannets can adjust their behaviour depending on whether the vessel is actively fishing or not, and also based on the type of fishing gear carried.
Dr Mark Jessopp of the Coastal & Marine Centre at University College Cork, a co-author of the work, added: “The fact that birds responded differently to boats depending on whether they were fishing or not, and the type of gear they were carrying, indicates just how finely attuned these animals are to the opportunities humans can provide”.
The findings help to understand the spatial influence of fisheries, which is critical to marine planning and policy – including shipping, offshore development, bycatch and fisheries themselves.
Co-author Professor Stuart Bearhop, also of the University of Exeter said: “We know that seabirds are facing many impacts within the marine environment, and we have tended to think that interactions with fishing boats were a localised phenomenon. Our work indicates that the scale of impact on these top predator’s behaviour is much broader.”
Gannets are the UK’s largest seabird, foraging up to 500 km from their colonies. They forage almost exclusively during daylight hours, with birds resting on the sea surface at night. They are visual foragers with no external nostrils and relatively small olfactory bulbs.
All fishing boats greater than 15 m in length must carry a GPS transmitter as part of the European Union Vessel Monitoring System.
From The Guardian
By Cris Sellarés
