Two populations of an animal which thrives on two UK islands are to be removed. These are populations of invasive brown rats which are accused of threatening the future of several species of locally rare seabirds.
The human inhabitants on one of the islands, St Agnes, have been consulted and they have given a unanimous go-ahead for the rat clearance on their remote homeland and the neighbouring isle of Gugh.
The Scillonian archipelago plays host to breeding populations of 14 seabird species (approximately 20,000 birds) but for years one of the major threats to the mainly ground-nesting birds has been rat predation of eggs and chicks. England’s only colony of storm petrels is said to be at risk from the rats, as is the local population of Manx shearwaters – for which the UK has a global responsibility.
The project aims to protect and restore the seabird population on the islands, which declined by almost a quarter between 1983 and 2006. Such birds are far outnumbered today by the brown rats which, according to a feasibility study, have a total Scillonian population of more than 34,500. Around 3,100 rats reside on St Agnes and Gugh, which happen to be close to the seabird breeding isle of Annet.
Julie Love, of the Isles of Scilly Trust said that “the feasibility study showed that rats can swim across from St Agnes and Gugh to Annet,”, “they eat both the eggs and the fledglings – in fact rats are even known to eat the rare Scilly shrew.”
David Mawer, the Isles of Scilly Trust senior conservation warden, added: “Seabirds already attract visitors to Scilly, and this project and the clever use of technology can reveal more of their fascinating lives, whilst leaving the seabirds free from unwanted disturbance.”
The rat-removal operation will take place in winter months and use special bait stations to prevent poisoning of non-target species.
Tony Whitehead, of the RSPB which is involved in the project, said “It is worth bearing in mind that it’s ten years this year since we removed rats from Lundy – with a resultant increase in seabird numbers. The Manx shearwater numbers there are now up by 250%”.
“This is part of a global push to restore island seabird populations from the teeth of invasive species,” he added.
Read more on the Isles of Scilly Seabird Recovery Project read here and details on the rat eradication here
For a detailed account of the rat eradication programme on Lundy Island dowload Conservation Evidence paper here
The current cold spell in north-west Europe will have been accompanied by the usual media activity in many places. Much of the news generated will focus on the regular “why weren’t we better prepared” headlines. One group, however, that know exactly what to do when snow comes in the area are the many thousands of birds that winter in the region. While resident birds not used to such cold weather might have to make do, those species that have come from further north are quick to up and move until they find something more suitable. The most obvious places for these versatile wanderers to head for are the coast and offshore islands that are usually much milder than inland areas. And so, with the snowfall on Friday, Jersey welcomed many thousands of new arrivals.
The usual clue to a cold-weather migration of this sort is the presence of lapwings on verges and every small field. While big flocks might develop in areas like the fields around St Ouen’s Pond, lapwings may happily feed alone in much smaller areas. The 2-300 lapwings on the Island on Thursday had been joined by possibly over a thousand more by Friday. Several small flocks of golden plovers came in with the lapwings – these two birds often join together in winter.
The other abundant and obvious visitors are the thrushes. There were already plenty of wintering redwings on the Island but on Friday morning they were joined by many thousands more that had arrived across the parishes in fields and gardens alike. New blackbirds and song thrushes had arrived too and were obvious as they tried to feed on the roadside at first light. Fieldfares, a bird formerly more common in the Jersey winter when winters were much colder than now, had also come in but only in smaller numbers so far. Interestingly, there are many less waterbird arrivals like ducks and grebes suggesting that so far it is only snow on the fields moving the wanderers and not the kind of cold temperatures that freeze ducks out of their ponds.
Today we reached a significant milestone when the 2,000th data sheet was input into the Farmland Bird Monitoring database. The first sheet, from Crabbé, was filled out on 1st April 2005 when we made 45 records involving 100 birds of 15 species. The 2,000th sheet, from Les Creux on 19th January, detailed 144 records of 729 birds from 25 species – an event greatly helped by the arrival of heavy snow. At the beginning of this long-term survey there were only five sites being monitored but that has now increased to 18 transects at 16 sites covering farmland, parkland, woodland, heath and unimproved grassland. To date 160 bird species have been recorded including six escapes (three living wild), two feral and two introduced species. The species total includes two identifiable subspecies of white wagtail (most records go under just the one catchall race!) and two yellow wagtails. We have so far input over 80,000 records detailing 200,000 birds!
The data collected in this survey is not suitable to estimate the size of our bird populations at any of the individual sites or for an overall Island figure. This form of consistent data collection does, however, provide a fantastic tool for seeing how our birds are faring both within a year and from year to year.
Each fortnight, 21km of transects are walked once whatever the weather. To date, 24 observers have contributed records with a core of around 10 real diehards who laugh off the horizontal rain and the attention of the many dogs we seem to meet on each transect. The real benefit to a scheme like this will only begin to be seen several years after the start as long term trends in our bird populations become apparent. While some transects have now been counted for nearly eight years others have come in to the project much more recently. The database will allow us to look at population trends at single sites or at combinations of sites. Obviously the biggest benefit will come from the biggest size of dataset and at the moment that is the set that comprises of the five original sites (Les Landes, Crabbé, Les Creux, Les Blanche Banques and Noirmont). In the future we will be able to run off graphs like that here for linnet from a combined dataset of maybe 16 sites. The greatest value of this project is in highlighting the status of our Island’s birds, of the environment in which they live and in planning for the future.
So, with this project…..
What are the most recorded species? Blackbird, robin, wren and great tit seem to be seen most regularly but possibly chaffinch is the most recorded overall;
What is the rarest? Luckily for the recorders several of the rarest birds recorded in Jersey have turned up on a transect during a count including solitary and buff-breasted sandpipers. Fan-tailed warbler and firecrest were first found nesting on a transect and the returning cirl buntings were found on one too;
And favourites? Each of the counters has their own favourites but the occurrence of bearded tits in St Ouen’s Bay and the possibility in season of migratory yellow wagtails, wryneck and ring ouzel are always highlights. However, little can beat finding a bittern or a long-eared owl stood on a transect staring at the observer!
And the least favourite? Well, surely there are none but some can be a bit tricky at times to pick out as they skulk or when their songs resemble others -dunnocks and garden warblers stand out here (or are too high-pitched for ageing recorders like me);
And the saddest? The loss of yellowhammer and steady declines in stonechat and skylark numbers are perhaps most poignant;
And the next species? Well, there are some obvious candidates but surely it will be red-billed chough!
Gianna was caught up for x-rays on the 18thafter a long course of anti-inflammatory drugs (Metacam) had made little improvement on her condition. The x-ray showed a fracture in one of her digits on the left foot that had tried to heal unsuccessfully. This explained the large amount of swelling that had developed around the digit. The vets applied a bandage to the foot designed to provide pressure relief on the joint and encourage her to use the foot. To prevent the muscles and tendons becoming locked up in one position the bandage will be changed weekly and alternate between having the foot in a flat position and a gripping position. Gianna was put back on a course of Metacam given in waxmoth larvae and kept in the shut off cage until treatment has finished.
Progress of the release aviary
As expected with any project there have been the inevitable delays. Gale-force winds and rain stopped play on couple of days, but Trevor and his team have continued to battle away. The polytunnel hoops are in place as are the framework for the shed. Various holidays this month meant that work stopped on the 15th and will resume in the first week of January. Durrell’s Bird Department staff visited the site on the 4th to see the build and offer moral support to Trevor and Jason in the form of gingerbread. I think it did the trick, except now they are placing orders!
The Farmland Bird Monitoring project has been further enlarged to include two new woodland sites. The new sites, at Rozel Manor and La Poudretterie (du Scez) near La Saie in St Martin increase the number of woodlands monitored to five with St Catherine’s Woods, Fern Valley and St Peter’s Valley. They also increase the overall project to 18 transects at 16 sites, each to be visited once every two weeks throughout the year. The two new transects are 843 and 1,543 metres long respectively.
The two new sites are both privately owned and monitoring is done with the kind permission of the owners. Birds recorded will be entered into the project database but will also be used for woodland management trials aimed for 2014 as part of a joint project by the Department of the Environment and Game & Wildlife Conservation Trust.
Early visits to the two new sites have found that all the expected birds are present including great spotted woodpecker, goldcrest, short-toed treecreeper and common buzzard. The real excitement, however, might be more in seeing which species are there during the breeding season.
2013 is shaping up to be a special year for Northern Ireland’s only breeding pair of chough. The pair spent this Christmas at home, a first for the country’s rarest breeding bird.
In 2012, for the first time, the chough bred on the RSPB’s Rathlin Nature Reserve where the RSPB are managing a large area of land for chough and where the birds can be seen feeding throughout the year. In previous years the birds have left the Island around late October and disappeared from the north coast until February when they return to prepare for a new breeding season.
Chough outside of Northern Ireland usually spend the winter roosting on or near their nest site. However, in the past the Rathlin birds seem to have fancied a change of scenery and despite the best efforts of the RSPB, their location in winter has remained a mystery.
The RSPB think the young from the previous two years are spending winter apart from the parent birds, on grounds somewhere on the north coast.
Michael McLaughlin, RSPB Agri Environment Officer commented, ‘The reason the birds are staying this late in the year is most likely due to the great work of several dedicated landowners on the north coast who take on targeted chough habitat management.’ This type of specific land management is carried out with the help of RSPB advisors, through DARD (Dept of Agriculture and Rural Development) Agri Environment Schemes and gives a lifeline to some of Northern Ireland’s rarest species, including the chough.
In the summer and winter chough are most often seen at Rathlin on land managed for them under the scheme, which provides excellent feeding and entices them to spend the whole year at home instead of moving away for the winter. The RSPB’s reserve on Rathlin is perfect for these birds, the reserve is also extremely important for other species including corncrake, breeding seabirds, plants and the illusive hare.
A further bird monitoring transect has been added to our Farmland and Coastland Bird Monitoring Project. This transect, a second in the Sorel Point to Mourier Valley area, is the 16th that we are counting birds along. As with the other transects (15 at 14 sites), this 1,070m path will be visited once every two weeks from January 2013 and all birds present recorded. The new transect runs along the National Trust for Jersey land on the south of Le Don Paton. This land will be farmed in a rotation that will be beneficial to wildlife with some of the fields providing food for birds each year. In December 2012 there are over 200 linnets feeding in these fields with good numbers of chaffinches and meadow pipits present. Up to three marsh harriers are regularly present and migrant birds such as swallows and winter thrushes will no doubt be recorded at the right time of year. The new transect compliments the existing Sorel to Mourier Valley transect that runs along the cliff path.
The project’s monitoring guidelines are available for download here
With obvious concerns about how Jersey’s choughs may contend with the potential threats in their environment, it is reassuring to hear these thoughts on the birds that naturally recolonised Cornwall.
Cornish Choughs note that choughs are really feisty, they certainly punch above their weight using their feet and talons as weapons, often tackling birds much bigger than themselves. Sometimes they make contact in mid-air, it is nail-biting watching a male chough attempt to grapple with a peregrine and the famous Lizard male sustained a serious injury to a leg a few years ago after fighting off a herring gull. Choughs often walk along with a pronounced limp and can have slightly deformed legs where they have broken and healed wonkily! These images by Colin Seager show immature choughs practice fighting – all good preparation for defending a territory in later life.
Claire Mucklow from the RSPB’s Cornish Chough project personally adds that from her experience choughs think they are invincible – and mostly they are!
Update from Regis Perdriat LPO Station at Île Grande in Brittany
There has been much interest in Jersey with the three choughs that appear to be setting up home in the Sept Îles Reserve. As potential colonists at the reserve, their choice of feeding habitat is interesting and is being monitored closely. The three birds move between two of the islands, Bono and Île aux Moines and feed mainly in the areas of maritime grassland or “silene maritima” lawn. There are still good areas of this habitat in patches along the Jersey coastline so it will be interesting to see if birds prefer this habitat in Jersey or whether they prefer something more agricultural. There are particularly obvious similarities between the photographs taken at the Sept Îles and Les Landes and Petit Plémont.
On the 7th Gianna was taken from quarantine to the vets to be x-rayed under anaesthetic and then moved to the shut-off cage in the Display Aviary to join the two breeding pairs. She weighed 294g on leaving quarantine which is an average weight for our adult females.
When she first went into the new aviary, Gianna was greeted by Tristan and Issy who sat on top of the cage and took a great interest in her. However, this interest was short lived and they did not really bother with her after that. Gianna was let out of the cage after a week so she could acclimatise to the new surroundings and the birds got to know each other. For the first fifteen minutes she quietly walked up and down the shelving at the back weighing up her options. The pairs were perched high preening each other and paid no attention. However, as soon as she vocalised, Tristan and Issy flew straight down and Tristan started fighting with Gianna. The contact only lasted a few seconds until Gianna flew up and circled the aviary a couple of times. Whenever she flew near Arthur and Gwinny they would display to her and sometimes chase her but it was only half-hearted. Once the hierarchy was explained, Gianna was left alone. She spends a lot of the time on the ground or on the rocks at the back left corner of the aviary.
With Gianna now in the display aviary and getting attention from the keepers, the other choughs perch lower and come down to the ground when the keepers are present, making the exhibit a lot more interesting for the public.
After a few days of being mixed, Gianna was seen to be holding up her left leg quite a bit. Often birds do this to thermo-regulate but they usually swap between legs. The fact that she was using the same leg became a concern and the problem became more pronounced so on the 27th she was caught up to be seen by the vet. She can grip with her left foot but doesn’t want to put any weight on it. The left leg felt slightly warmer than the right which could suggest an infection. She was put on a five day course of antibiotic but showed no improvement. The course has been extended to see if that makes any difference before opting for more invasive measures. Gianna remains in the Display Aviary but is temporarily separated from the other birds.
It is interesting to note that Gianna has a higher pitch call than the other choughs. This could be a consequence of something she picked up whilst being isolated in captivity when young. Maybe it’s the Italian in her!
Trial of new ID rings for released choughs
When the choughs are finally released into Jersey and free to roam, we need to be able to follow them around and differentiate between individuals. There is always the possibility too that they may fly off the Island and head elsewhere. If they do, then people away from Jersey need to be able to identify that they are ‘Jersey’ choughs. For this reason we have been investigating the best possible ID ringing programme that will not conflict with UK or France ringing schemes.
We plan to attach a standard issue metal ring to one leg of the bird which will have the Jersey Museum address stamped on it. The address will only be visible if the bird is in the hand, e.g. caught in a mist-net, found injured/dead, or the observer is extremely lucky with their binoculars. A colour plastic ring will be also be used to identify individuals. All birds within the Durrell collection are fitted with plastic and metal rings so they are quite used to wearing them.
After discussions with Tony Cross, who is responsible for ringing Cornish and Welsh choughs, we have decided to try a new type of ring with the choughs. Darvic style incoloy (nickel-chromium alloy) rings are hard wearing rings used for coastal birds. They can be made the same diameter as standard chough rings, but are much longer allowing for a number to be engraved along the length. Paul Veron in Guernsey kindly supplied us with some perfect rings originally made for black-headed gulls.
On the 8th we caught up one of the juveniles not being released (B6977) and attached the new ring. She is now identified by “2A01” on her left leg and white on her right. After twenty days she was caught up again to check the fitting and make sure there was no rubbing or injury to the leg. The ring is free to rotate and so far no rubbing can be seen and she doesn’t show any particular interest in the tag which is also a good sign. She has put on 25g in weight since the tag was attached. This could simply be due to eating more as the temperature has dropped.
Radio-transmitter trials
This month, video cameras were placed in the two aviaries housing the juveniles during feeding time. One aviary houses the birds with dummy radio transmitters and the other aviary has the candidates for release, i.e. with no dummy transmitters. The aim of this was to see if there were any behavioural differences between the two groups. The weather restricted the number of days this could be done since the cameras are outside and not waterproof. However, we were able to get footage of the birds which is still being reviewed. At present there seems to be no significant difference between the groups. All birds forage and fly with no restrictions.
B6975 and B6976 were caught up on the 28th to check on the condition of the dummy radio transmitters and the birds themselves. The birds appear fine with minimal disturbance to the tail feathers. There was no further damage to the glued areas although it does look like one of the threads is looser than when first attached. An order has now been placed for the real transmitters to be built with delivery expected in January.
An interesting note is that the three birds under various trials in one aviary (SF2) are spending less time hiding in the nest-box when keepers are present. The other group (in SF3), chosen for release because they were more confident, still hide every time.
Progress of the release aviary
Planning permission for building a release aviary at Sorel was granted on the 13th. After preliminary meetings with the National Trust for Jersey and Aaron Le Couteur, the shepherd, groundwork began on the aviary.
The field where the aviary is being built will also be used to graze sheep in the spring. For this reason there needs to be a sheep-proof fence erected not just around the field but also the aviary itself. Hopefully, this will also act as a deterrent for the public getting too close to the birds. During the time we have been present at the site there have been dog walkers every day either next to or in the same field and often with their dogs off the leads. Whilst we do not want to discourage dog walkers in the area we do need to ensure that the birds in the aviary do not suffer any stress related to this. There will be publicity including messaging boards around the site to inform people of the project and ask for their support.
Trevor Smith from Durrell’s Maintenance Department is leading the build onsite with assistance from staff and volunteers. The first post went in in the ground on Friday 23rd and so far, despite battling the elements, Trevor has made great progress. Aaron Le Couteur has kindly loaned the team the use of his lockable trailer for equipment and water tank for the duration of the build. The weather will be the deciding factor on when the building can be completed, but we hope to finish by Christmas.
Two populations of an animal which thrives on two UK islands are to be removed. These are populations of invasive brown rats which are accused of threatening the future of several species of locally rare seabirds.
The Scillonian archipelago plays host to breeding populations of 14 seabird species (approximately 20,000 birds) but for years one of the major threats to the mainly ground-nesting birds has been rat predation of eggs and chicks. England’s only colony of storm petrels is said to be at risk from the rats, as is the local population of Manx shearwaters – for which the UK has a global responsibility.
