Airport skylark survey 2013

Jersey Airport. June 2013. Photo by Glyn YoungOn Wednesday, 26th June, we conducted our annual survey of the skylarks Alauda arvensis and meadow pipits Anthus pratensis at Jersey Airport. As ever, this is one of the hardest monitoring exercises we undertake each year. It’s also the only one where we need security clearance before even setting foot on the grass. The airport is obliged by law to manage its entire site to dissuade large birds from coming into proximity of the planes and the length of the grass throughout the area is very important. All bird-friendly plants are discouraged too but strangely both skylarks and meadow pipits seem to thrive here.

Jersey Airport is now almost the last site for breeding skylarks in the Channel Islands. None have bred at Les Landes for two years and, it appears, there are now none in St Ouen’s Bay away from the Blanche Banques where there are only a small number of birds despite protection for their nest sites. Sadly, now, even at the Airport numbers are declining although how much this is the impact of consecutive poor springs is unclear.

Jersey Airport. June 2013. Photo by Glyn YoungThe skylark team this year, Tony Paintin, Hester Whitehead and Glyn Young once again covered the grassy areas of the airport either side of the runway while remaining very visible at all times and keeping in radio contact with Air Traffic Control throughout. There are very sensitive areas that the team cannot enter and we all have to withdraw to a safe point when a plane is landing, taking off or taxiing.

Skylarks are never very easy to count as some birds can stay put in the grass while others fly up and sing at us. We walk out in a line and record each lark and pipit. Whatever the failings in our technique are though, we have used the same methodology since 2006, and we are beginning to see a trend in numbers developing. This year we counted only 26 larks, our lowest figure so far.


Singing   males

Flushed   birds      


Meadow pipits

15June 2006





12June 2007





5 June 2008





24June 2009





9 June 2010





27 July 2011





27June 2012

26June 2013










Once again we are indebted to the airport authorities for allowing us to count the birds and for helping with security clearance and for providing radios and high-visibility vests etc.

Radio and tv towers killing birds: the solution may be simple

Black-throated blue warbler. Photo by Kevin Grundy www.pannyfants.blogspot.comFrom ABC News

TV and radio towers, blamed for nearly 7 million bird deaths each year in North America are doing the most damage to species that can hardly afford the loss, according to a new study published in Biological Conservation.

In the United States and Canada, at least 97% of the birds that crash into the towers, or the guy wires that hold them up, are the tiny songbirds – mostly warblers – that are considered “birds of conservation concern”.

The latest study comes from the same researchers, members of the Los Angeles-based Urban Wildlands Group, that warned last year of the spiralling mortality of birds that are attracted to the lights, usually red, atop the towers. The lights are required by the USA’s Federal Aviation Administration (FAA) for any tower over 200 feet tall, and there are thousands in North America that are more than 10 times that height.

Black-throated blue warbler. Photo by Mick DrydenThe deaths usually occur during the nocturnal migration of songbirds, especially when the cloud ceiling is low and there is fog or rain. The lights create an illuminated area around the tower and it is thought the birds become confused, switch off their night navigation and begin to spiral around the tower. Some run into the support cables, or into each other, and plunge to the ground.

Travis Longcore, from the University of Southern California and lead author of the current study, said his group wanted to look beyond the sheer numbers and focus on which types of birds were suffering the greatest loses, based chiefly on the number of deaths compared to the overall population estimate of each species.

“Many bird species are killed at towers disproportionate to their abundance,” the study says.

Swainson's warbler. Photo from Powdermill Bird Obs, Pennsylvania“This lets us look at this (the tower deaths) as a factor in the trajectory of the population”. The study indicates that towers are a very significant factor for a number of species, especially small songbirds, some of which are declining in numbers overall.  The researchers found that 58% of the birds killed each year are warblers, including Swainson’s warbler Limnothlypis swainsonii, which loses 8.9% of its population each year, and the black-throated blue warbler Dendroica caerulescens loses 5.6%. It’s not just songbirds though, each year yellow rail Yellow rail. Photo by Sand Bluff Bird Observatory www.sandbluff.orgCoturnicops noveboracensis loses about 9% of its total population because of communications towers, many of which are taller than the Empire State Building.

In addition to communications towers, however, the birds have to fend off cats and other predators, and many are killed when they crash into windows, as urban dwellers know so well. So towers are only part of the problem, but this study suggests they may be more significant than had been thought, at least for certain species.

A solution?

Some recent experiments have shown that a flashing (blinking) light attracts fewer birds than a light that remains on. The FAA recently ruled that tower operators may switch to blinking lights, and some have done so. It could be too that when a steady light is replaced by a blinking light, the birds simply leave. This is not an expensive modification but the results may be immediate.

This research is, of course, based on estimates, some of which wildly disagree with estimates from other researchers, and that may be partly because the situation varies so dramatically across the country. And just simply collecting the data is difficult. Longcore pointed out that a dead bird doesn’t hang around very long.

“Scavengers and predators and decomposers are incredibly effective,” he said. In one case an owl was spotted as it zipped through the night sky and grabbed small birds before they even hit the ground.

However, sometimes it’s easier to find how many birds have died. Scientists found that an estimated 5,000 to 10,000 birds, mostly Lapland Longspurs, were killed on Jan. 22, 1998, near a 420-foot tower in western Kansas. It happened, as is often the case, during a heavy snowstorm. See bibliography of bird kills in USA here

And the number of kills from towers still lags far behind the estimated number of deaths caused by birds hitting windows. And still, the estimates vary widely. One group of researchers, for example, estimated that the number of window-kills was somewhere between 97.6 million to 976 million annually.

Longcore said he believes that if most towers are modified, just by switching to flashing lights, many more songbirds will be around to serenade us in our gardens.

The situation with tall masts in the Channel Islands is unclear. However, there are such things such as those on the north coast of Jersey and this may be an area for future research.


Back To Work at Sorel

By Liz Corry and Anna Plunkett-Cole

Back to Work's new sheep fencing at Sorel. August 2013. Photo by Liz CorryBack to Work and the National Trust for Jersey joined forces in March and launched a new volunteer scheme to undertake a wide range of conservation tasks and provide placements and skills training for locally qualified jobseekers.

The volunteer scheme, which has seen some 60 jobseekers improve their employability by completing a diverse range of projects from meadow restoration to maintenance of Trust properties, is among a number of projects being run by Back to Work.

In July a small team of jobseekers, supervised by Piers Sangan (Sangan Island Conservation Ltd.), were hard at work preparing ground and erecting sheep fencing up at Sorel. Two fields, owned by the National Trust, were sown with grass seed last year with the intention of providing extra grazing sites for the Manx Loaghtan sheep. However, the perimeters of the fields needed to be secured with fencing before the sheep could be moved in.

Back to Work sheep fencing at Sorel. August 2013. Photo by Liz CorryOne of those fields is the site of the chough release aviary and, therefore, the sheep fencing serves a dual purpose. Keep the sheep from straying and keep the sheep from the aviary! Whilst Manx Loaghtans are a mild mannered animal they will eat their way through just about anything and everything.

The team did a great job working in some of the hottest conditions of the year to date. Hopefully, the sheep will be able to reap the benefits of everyone’s hard labour in preparing the fields.

The Back to Work team is based at Social Security and was set up in response to rising unemployment in the Island. It administers all government employment schemes and explores new initiatives to reduce unemployment by working with employers and locally qualified jobseekers to provide sustainable employment opportunities.

Choughs fly again in Jersey!

Well, Wednesday afternoon (28th August) was rather exciting/stressful. We planned to open the shutters at the Sorel aviary to the outside world for 30 minutes at 1700. This first step should be considered part of the training for the birds rather than an ‘official’ release. The idea is that the birds get a few minutes outside each day with the access time lengthened slowly until the birds are left completely at liberty. While the birds may or may not choose to go out of the aviary they will be called in again after 30 minutes and shut inside again.

This soft-release process will be repeated daily until late-September when the birds may remain at liberty unless specifically called back in (they will be fed daily and watched closely for the foreseeable future whatever happens). The first opening of the hatches was not made into an event, mostly because something could have gone wrong or, much more likely, they would not actually go out at all on the first day.

Release Day 1 (28th August)

The first chough out (PG). 28-8-2013. Photo by Annette LoweFirst flight! Photo by Rick Jones, DurrellThe shutters were duly opened at 1700 and we had 30 minutes of ‘freedom’ and three birds wandered outside. One chough flew round a bit but not far from aviary and came in when called. Not a bad start! The birds behaved very well and the value of training and Liz’s hard work were obvious. Target platforms have been put up outside of the aviary to give the birds their own and recognisable perching spots outside the aviary.

Listen to BBC Radio Jersey’s Tori Orchard interview with Glyn Young on the morning of the first ‘release’ (it’s also No 7 in the series of Tori’s interviews here).

Day 2 (29th August)

The ‘release’ process was repeated today when four birds ventured outside including ‘senior pair’ MV and PG. One bird, RD, failed to grasp the idea of the entrances and failed to find its way back inside and spent all night on the aviary roof before going back inside early on Friday morning.

Day 3 (30th August) – the day we discovered that choughs have minds of their own!

The senior pair (well, they are two years old) ventured rather further afield today and decided to explore nearby Ronez Quarry.  There was a heart-in-mouth moment when we watched a peregrine attack the pair but they recognised the threat and, in mid-air, on the longest flight of their lives fought it off – during the attack the falcon grabbed one of the chough pair by the legs but let go pretty quickly. One chough went to ground to avoid the persistent falcon but the pair were quickly re-united and seemed unfazed. That’s the first peregrine encounter out the way, let’s hope that any more have the same outcome.

Choughs return to Jersey. 1st September 2013. Photo by Colin StevensonWhile we can observe the choughs directly, allowing us to follow their activities and check on their wellbeing, the radio transmitters allow us to track the choughs at all times. On Friday the pair moved around confidently, foraged on the ground, displayed, flew out over the sea, perched on a woodpile and generally behaved like ‘wild’ choughs. We quickly learned that the choughs and the local carrion crows just ignore each other now that they can really meet.

Choughs on Jersey's coast again. Photo by Colin StevensonThe radio tracking team went into action and have, over the weekend, recorded the pair’s locations following a research protocol devised in advance. Having said that, the pair have at times been very visible and have appeared over Sorel Point and around the car park. Often they call loudly.

On Friday night the now christened Ronez 2 slept inside one of the quarry’s conveyor belts! They were up early Saturday morning and have continued to put on a good show. Never once have they gone near the aviary even though we know they’ve been able to see it when flying up high. The pair have once more encountered falcons and were seen to actively mob them.

Chough near Sorel Point. Photo by Liz CorryThe free-flying pair seems quite happy in and around the quarry and slept again in or near the conveyor. Wild choughs regularly live in quarries, including in North Wales, the ancestral home of our birds (see video of choughs in a quarry here). There is water in Ronez Quarry, secure roost sites and, hopefully, lots of foraging opportunities and respect from the quarry owners and personnel. The pair has been seen regularly on the grass at Sorel Point. Even with the Ronez 2 out and about, we will continue the slower soft-release of the other five birds but are wary that they have temporarily lost the presence of their senior members. Well, lost them unless they go and re-join them in the quarry!

Red-billed choughs near Sorel Point. September 2013. Photo by Liz CorryNow that there are birds out on the coast, please don’t hesitate to send in your sightings. Check here for details.

We are very grateful to the team-members who have assisted us in observing the release. Alison and Ray Hales from Paradise Park (Operation Chough) have been watching the birds with us all weekend. Mike Stentiford, the project’s staunchest supporter from when it was first imagined was there for the first opening. We must also give sincere thanks to Ronez Quarry who may get to see a lot of the choughs and of us!




Chough report: July 2013

Report by Liz Corry

Sorel fog, July 2013. Photo by Liz CorryChoughs at Sorel

The Sorel choughs have had an ‘eventful’ month, no doubt further building their anticipation for release.

Sunbathing choughs. July 2013. Photo by Liz CorryFirstly they have witnessed a variety of impressive weather fronts. Mystical rolling sea fogs, scorching heat devoid of any cooling breeze, and some impressive thunderstorms. In an ‘exposed’ aviary such as the one at Sorel there is always the worry that the birds do not have enough appropriate shelter or shade. It helps that choughs are a hardy species. More importantly they are always being monitored by keepers and the aviary has been designed with shelter points in mind. A bit like dogs, birds will pant and stand open-mouthed when extremely hot. Fortunately without the slobbering. Extra drinking and bathing water was provided when necessary. The fog didn’t really cause any problems for the birds and the drop in humidity was probably a welcome relief. The birds may have also appreciated the blanket of secrecy provided by the fog as they had very few visitors.

Rodent damage at Sorel aviary. July 2013. Photo by Liz CorryWhile the birds have had only a few non-human visitors besides dogs out on walks, there has, however, been an increase in rodent activity in and around the aviary. This was expected as the months go by and seasons change. Something, most likely a field mouse, has been testing the durability of the aviary netting.

In response to the rodent visitors, a specialised rodent-deterrent paint was applied to the netting around the perimeter of the aviary. The idea is that the rodent is put off from chewing because of the nasty taste. Normally the netting is pre-soaked before being used. Durrell has recently started testing the effectiveness and the aviary at Sorel became the most recent test subject. Unfortunately it appears Sorel mice do not object to the taste. On the plus side Sorel mice are not very adventurous/intuitive and have only focused on one tiny corner. Keepers seem to be winning this battle!

The pair of peregrines that patrol the Sorel-Crabbé cliffs started moving inland towards the end of July. They have been spotted close the aviary on a few occasions, but don’t seem to show an interest in the choughs. Their presence is likely due to the increase in stock doves foraging in the neighbouring fields. As long as the peregrines have plenty of existing food resources we hope they will not need to add soon-to-be-released chough to their menu.

Radio transmitters and veterinary health checks

Moulting process in chough tail feathers. New central feathers growing in, outer ones still to drop. July 2013. Photo by Liz CorryOn 9th July three of the choughs were caught up to look at their tail feathers and assess what stage of their moult they were at. We wanted to look at the three youngsters because one of them was the first to drop its radio transmitter, i.e. it had moulted the central tail feathers. The other two never had a transmitter and would, therefore, provide an interesting comparison.

The chosen three were isolated from the group by calling them down for food and encouraging them into a section of the aviary sealed off by closing hatches. They were then caught in hand-nets by Durrell bird keepers who don’t work at Sorel  (the choice of staff was to avoid any negative association the birds might develop if Sorel keepers were to do it). In the safety of the keeper porch a quick assessment of their moult score for tail and primary (wing) feathers was made.

Attaching radio transmitter. July 2013. Photo by Liz CorryAll choughs moult their tail feathers starting from the centre and working outwards. They start growing new tail feathers at the same time as their primaries (wing feathers) but complete the tail moult before the primaries are complete. All three of our choughs were at a similar stage in that only their central four tail feathers had started moulting. This meant that they definitely were not ready for new transmitters to be attached, but could well be in a few weeks.

A second catch-up was carried out on the 26th when all the birds needed to be given an injection of ivomectin to protect against possible gapeworm infections. Due to timing constraints only four could be caught up. The remaining three were caught up on the 30th.

In the first group, which happened to be all the older juveniles, only one was ready for a radio transmitter. The others were still moulting through the central tail feathers. From the second group, two were ready and had transmitters attached. The remaining birds without transmitters will be caught up again towards the end of August by which time they should have new, stronger, tail feathers.

Whilst in the hand there was the opportunity for a quick general health check of feet, eyes and beak. All looked good and with no obvious sign of a gapeworm infection. There has been one female that developed a slight limp. Her leg was looked at but there was no sign of injury or bumblefoot and the vet was happy with her condition.

Radio tracking team

After advertising through this website, via social media and on Channel TV we have managed to fill the positions for radio-tracking assistants. The team of three are all local to the Island and bring with them a range of skills and experiences beneficial to the project. Training will begin in August prior to the imminent release of the choughs.

Behavioural Observations

Jess Maxwell has had to finish her observations early due to other work commitments. We are trying to carry on with this study up until, and possibly after, the birds’ release. Myles Lamont, Durrell student, is helping out with these until he leaves to join Durrell’s Mauritius programme in mid-August.

Habitat management at Sorel

Mowing field by Sorel aviary. July 2013. Photo by Liz CorryThere have been several different activities going on at Sorel over the last month benefitting the BOTE project. At the start of the month the farmer and his team were out on the NTJ fields harvesting potatoes. This seemed to provide much entertainment for the choughs as they spent less time watching the coastline and more on the farm workers. My guess is they were eyeing up the soil for insects and probably became insanely jealous.

Aaron, the shepherd (CS Conservation), has been very busy shearing the sheep which of course involves the onerous task of rounding them up first. The sheep range over both sides of Mourier Valley so the task takes several days and two very energetic Border collies. The choughs were a little on edge whenever a small flock of sheep would run past, but who wouldn’t be. On the whole, however, they paid little attention to what was going on.

A team from the Government run Back to Work scheme spent several days erecting sheep fencing around the aviary and the field perimeter. Back to Work is a voluntary scheme for qualified jobseekers which aims to provide them with skills beneficial for the workplace. They teamed up with the National Trust to work on several conservation projects including this one at Sorel. The population of sheep at Sorel has grown over the years and they now need to expand their grazing sites. Now that this field has been securely fenced the sheep can be moved in when needs be.

Once the fencing was in place Aaron set to work cutting back the dry, long grass. Great care was taken in using the tractor so close to the aviary. The design of the aviary allows the birds to ‘escape’ to either end depending on where the tractor/disturbance is. Once cut, a team of volunteers organised by the NTJ went up to the site and raked the cuttings into lines. This allowed Aaron to go back at a later date and quickly gather and remove the hay.

Bracken clearance by aviary. July 2013. Photo by Liz CorryOn a less intensive scale, albeit very laborious, work has begun to remove bracken on the embankment that runs alongside the aviary. This will benefit the choughs in that more ground will be exposed for foraging and obstructions from in front of the release hatches have been removed to encourage bird movement back and forth.

Neil Singleton, chough field assistant, kindly volunteered his time to help me pull out the bracken and stinging nettles. Due to the vast quantity of Slow worm by Sorel aviary. July 2013. Photo by Liz Corrybracken, the green waste was taken off site and burnt on Durrell’s fire pit. We have unearthed some interesting finds including a crapaud (a common toad for non-Jersey readers), a slow worm, and sadly a very dead green lizard. The removal of the bracken has also uncovered the hedgerow saplings planted in previous years by NTJ volunteers: a lot had suffered from being smothered by the bracken but some still stand firm and will hopefully continue growing. This work is ongoing.


Cirl buntings – good news from Grouville

On Monday we reported on the fire at Grouville Golf Course and the devastating impact it would have had on local wildlife. The focus of the report was Jersey’s only known pair of cirl buntings and what effects the fire in their breeding territory may have had. After the fire the birds were nowhere to be seen and there was justifiably a lot of concern for their wellbeing. Well, today we found out what happened to them! Almost exactly a year to the day after the first Jersey-bred cirl buntings of recent years were found, and rather late in the year again, what appears undoubtedly to be a chick was seen with its father and photographed by Mick Dryden. The female bunting was seen nearby but we don’t know yet whether other chicks were around – visit Jersey Birds for updates.Father and young cirl bunting. 31st July 2013. Photo by Mick Dryden.Father and young cirl bunting. 31st July 2013. Photo by Mick Dryden.


Fire destroys cirl bunting habitat in Grouville

Grouville fire. 24th July 2013. Photo by Richard Perchard

Male cirl bunting before the fire (June 2013). Photo by Romano da Costa the night of Tuesday 23rd July a fire broke out on the edge of the Royal Jersey Golf Course in Grouville. As well as threatening nearby houses and the infrastructure of the golf course, this fire destroyed important parts of the habitat of our one known pair of cirl buntings. The fire was successfully put out by the Fire Service but not before significant damage to wildlife had occurred – besides the cirl buntings there would have been green lizards and slow worms in the area.  Richard Perchard’s photo of the fire damage was taken at the site of one of the buntings’ feeders, luckily Richard had moved this feeder to another spot that the fire avoided a few months ago.

The spell of hot, dry weather in Jersey always brings the threat of furze fires and disappointingly there is suggestion that this fire was the result of vandalism and may have been started by fireworks. A criminal investigation is underway in the hope of discovering the true cause of the fire and, hopefully, bringing any culprits to justice (see report here). The cirl buntings have not yet been re-sighted and we had hoped that they were nesting as last year young were seen in late July.

The 2013 Inter-Island Environment Meeting is announced

Pleinmont Point, Guernsey. Photo by States of GuernseyThe organisers of 2013 Inter-Island Environment Meeting cordially invite you to Guernsey. This year’s event will be hosted by La Société Guernesiase at the Frossard Lecture Theatre in Candie Gardens on 17-18th October. There will also be an optional field trip planned for the Saturday (19th October).

Candie Gardens. Photo by States of GuernseyAt this stage the organisers would like to have some idea of numbers of delegates, topics and numbers of speakers, so if you are interested in attending the meeting or speaking at the meeting please contact the organisers by 31st July (e-mail address at bottom of page).

Talks/presentations are invited from anyone.  At this stage there is no focus on specific topics but they’d like to develop themes along the lines of “Strategies & Cooperation for Action” and “Engaging with the Community to promote Biodiversity”.  Please do not be put off by these titles – a mix of topics from terrestrial to marine as well as general and from as broad a spectrum of the “Environment Community” as possible will be welcome.

Yarrow Broomrape. Photo by Andrew McCutcheonTo help you with your planning the Organising Group for the Meeting has agreed the following:
• Start time on Thursday 17th October 10am (preceded by coffee/registration from 9am)
• Timings for the first day will be10am – 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)
• There will be an optional field trip on Saturday 10am – 1pm. Sites to be confirmed.  Optional lunch out afterwards.

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 has yet to be decided and will depend on the level of any sponsorship – it is anticipated that a fee of no more than £25 per person will be collected at registration.

Delegates are responsible for all their own travel and accommodation arrangements.  For details of travel to Guernsey see e.g. Aurigny, Flybe, Blue Islands or Condor and for accommodation see Visit Guernsey

The event may be limited to a maximum of 70 delegates.  Whilst the organisers are not expecting a “sell out” they reserve the right to turn down bookings to encourage broad representation from the region and beyond (e.g. the Isle of Man and UK etc.). They look forward to hearing from you and to sharing what they hope will be an enjoyable and thought-provoking Inter-Island Environment Meeting!

Please e-mail the Guernsey Biological Records Centre at for more information and to book a place and what will undoubtedly be an exciting event.

Birds On The Edge Farmland Scheme shortlisted for top local conservation award

By Cris Sellarés

Earlier this month BOTE’s Trial Farmland Scheme was entered into Insurance Corporation of the Channel Islands’ 2013 Conservation Awards and, visited by the judging panel, shortlisted for this year’s award.

The judges for the Insurance Corporation Conservation Awards and BOTE Project Officer Cristina Sellarés at the conservation fields in the north coast.The judges’ site visit was organized and BOTE Project Officer, Cristina Sellarés, was able to show the judges the agricultural fields that are being planted with bird conservation crops once the potatoes are harvested. Cris also explained how these important crops will help our local birds survive the winter, whilst not costing the farmer any extra money thanks to the scheme sponsors. Whilst we are sure that this fine example of habitat restoration project that BOTE is promoting within the local community got the judges’ interest, the main prize was awarded to a marine conservation project by another local organization, Jersey Seasearch, which aims to give young people the opportunity to proactively take part in the protection of our local waters.

Congratulations are in order, so well done Jersey Seasearch! And as for us, we’ll carry on with our work, happy in the knowledge that from this humble scheme we are doing our best for the local birds, the coastal habitats and the Island’s community.

Calf of Man: remove rats to restore seabirds

Calf of Man. Photo courtesy of Manx Heritage

The Calf of Man

The Calf of Man is a 250ha island lying only 500m to the south of the Isle of Man (read more here). It was once home to thousands of nesting Manx shearwaters, the burrowing seabirds that got their common name from these islands. However, brown rats (also known locally as ‘longtails’) landed on the island from a shipwreck in the late 1700s. The rats proceeded to wipe out the huge Manx shearwater colony, and since then only a few of these iconic birds have managed to breed on the Calf. During the autumn and winter of 2012-2013, a team from Manx National Heritage, the Manx Wildlife Trust, Manx Birdlife, the Isle of Man Department of Environment, Food and Agriculture, the Animal Health and Veterinary Laboratories Agency (AHVLA) and the Royal Society for the Protection of Birds worked to eliminate rats from the Calf of Man and make the island safer for all nesting seabirds and encourage the resurgence of the shearwater colony.

Calf of Man. Photo courtesy of Manx HeritageThe small island is dominated by maritime heath, bracken/bluebell and grassland both semi-improved and maritime. Small patches of wet flushes, marshy grassland and rock outcrops all go to form a diverse landscape. Over 340 species of plant have been recorded. Red-billed choughs breed on the sea cliffs and Atlantic puffin once bred on the island but their decline and eventual disappearance are likely to be a result of the rats’ arrival.

The rats and the seabirds

Rats will eat the eggs and chicks of almost all nesting seabirds that they can get to and have been known to kill the adult birds too. There is evidence from all over the world that where rats are present on seabird islands, the seabirds suffer large losses from rat predation. However, not all is lost. There are increasing numbers of programmes to remove rats from seabird islands and there is dramatic evidence of their success even in local waters. Following a rat eradication programme on Lundy Island in the Bristol Channel between 2002 and 2004, monitoring of burrows in 2008 showed an estimated 1,081 pairs of Manx shearwater, an increase of 250% in numbers since 2001.

The Calf project team expects that seabird breeding productivity on the island will start to recover immediately following the eradication. An anti-coagulant bait block, a “first generation anti-coagulant” called Coumatetralyl, was used to kill the rats. This acts by blocking the synthesis of vitamin K and causing internal haemorrhage. The bait was administered in boxes or pipe tunnels to which rats could gain access. Simple blocking devices were needed to discourage entry by young rabbits and birds such as crows.

Poisoned rats typically die below ground in burrows and are unlikely to be eaten by predators such as ravens and gulls. Although secondary poisoning of non-target mammals or birds could not be ruled out, the use of Coumatetralyl was particularly appropriate for environmentally sensitive applications due to its low persistence and low toxicity to birds. A risk assessment was completed for key non-target species on the island particularly for the wood mouse which, although not recorded on the Calf for some time, may still survive. Live traps were maintained in the hope of catching mice for transferral to a safe place and return following the eradication operation. However, no wood mice were found, though the project team suspect that some have survived the rodenticide deployment. Pigmy shrews, an insectivore unlikely to be attracted to the poison bait and Loaghtan sheep were not affected by the poison through careful management of the bait. To the surprise of the team, some young rabbits seemed to be attracted to the chocolate wax blocks used as non-toxic monitoring bait after the eradication phase.

Although also an invasive mammal, rabbits are desirable on the Calf as they provide burrows which shearwaters and (hopefully) puffins can use. Together with Loaghtan sheep, they help keep the grass short which benefits other wildlife such as choughs and low-growing herbaceous plants.

How do you know if eradication has worked?

Following the main eradication phase, chocolate wax-blocks were placed around the Calf, particularly to the coastal fringes where any re-infestation might occur.  It will be necessary to monitor these points into the foreseeable future and certainly for the first two years after eradication in case there are any remaining rats not dealt with during the intensive baiting phase.

Is there a risk of re-invasion?

The project team cannot be sure that rats will not re-colonise the Calf of Man, but they can minimise the risk of a new invasion. Quarantine for all boats and ships that plan to land on the island will need to be enforced and it is hoped that all boat owners who like to frequent the Calf will co-operate fully with all requirements.

Unauthorised landings and shipwrecks will remain a threat but much less so than in the past because of more hygienic conditions on board and tighter controls on landing.

Since rats are able to swim, it is conceivable that they could reach the Calf across the Sound via Kitterland but it is anticipated that the generally strong tidal conditions may reduce this risk.  Monitoring will continue on Kitterland periodically to detect any build up of rat numbers and allow a fast response to eliminate them.

At the time of writing the project team remain cautiously optimistic, despite one suspicious incidence of rat sign which has been dealt with by means of localised intensive baiting.

Do similar situations exist in the Channel Islands?

Yes. Rats may be the main reason that puffins are so rare in Jersey and shearwaters barely survive in Sark. It is probably hundreds of years since a Jersey puffin nested down a proper earth burrow, those that have nested have done so in rock crevices and fissures that the rats can’t reach. Manx shearwaters and storm petrels were probably also widespread here once. Today the Islands’ only real hope for burrowing seabirds is Burhou. This island is rat-free but if any rats ever reached it we could lose all these
puffins. There are plenty of rats on our north coast and while it would be much harder to remove them from areas like Tête des Plémont it is not necessarily impossible. But it would take hard work and a long term commitment and, who knows, maybe Jersey’s puffins could once again be safe and shearwaters once again nest here.

Sincere thanks to Kate Hawkins, Curator: Natural History, Manx National Heritage for helping compile this report.