Chough report: October 2013

Choughs at the Sorel Aviary. Photo by Liz CorryBy Liz Corry

Sorel Choughs

Green and Mauve’s ventures into the quarry came to a temporary close this month after a mysterious turn of events. Ronez Quarry personnel phoned the team to report sightings of the pair in their machinery rooms at the bottom of the quarry. In itself, this Mauve returning to aviary and weighing herself. Photo by Liz Corrywas not unusual but, as it was during the day and the workers were testing out equipment, there were concerns for the birds’ safety. From the reports it seemed that the birds were actually quite calm, perched in the roof space watching the workers below. The real concern was raised when Mauve returned to the aviary minus her partner and minus her radio transmitter.

It is not possible to say how she lost the transmitter. In flight it was clear to see she was missing the two central tail feathers that would have been attached to the transmitter and closer examination showed they had come straight out at the base rather than having snapped off. Maybe she got them caught or something tried to grab her by the tail. Other than the absent tail feathers she was in good health and her body weight was fine.

Meanwhile, Green’s signal had not moved from the building. A site visit was arranged in the afternoon thanks to Ronez to see conditions inside the building and to try to locate Green. His signal was loud and clear but he was not visible. With a bit of detective work he was finally located outside the building on the lower bank. Mauve’s signal (from her missing transmitter) could not be picked up in the area or along the coast. A quarry worker reported seeing one of the choughs with missing tail feathers whilst in the building earlier so we assume she lost them in the quarry, and the transmitter has been broken or the signal is being blocked.

When Green finally made an appearance he was looking a little subdued. Maybe confused as to where Mauve had gone and stressed at being by himself. Fortunately for him, Black was close by and excitedly calling for food when we appeared. This caught the attention of Green who flew closer to Black. After lots of frantic displaying/flirting by Black, Green joined her and then joined her in the supplementary feed.

The next day saw both Green and Black appearing for food each time the we called them. Until that is they flew back to the aviary on their own accord at the end of the day. We tried to get them back inside the aviary, but the onset of thunder and lightning spooked the pair off the aviary roof and back to the safety of the quarry.

Black taking supplementary feed inside quarry. Photo by Liz CorryIn the morning, Green and Black were back at their normal spot in the quarry. An all-day motocross event at Ronez Point, however, meant an alternative supplementary feeding site had to be found. Luckily with the team having access to the upper level of the quarry they could go in and approach from a different angle. Green was spooked by the use of the catapult, having never seen it before, and flew off across the quarry. Black followed but for some reason turned back halfway and returned to feed. Green continued to fly over the 4 X 4 race day going on at Sorel below him and on to the aviary.

Green’s return was certainly welcomed by Mauve and the others, but the whole atmosphere seemed a little subdued. From observing him over the afternoon it was clear that he was not himself. His feathers on his front and the skin on his feet were grey and ‘muddy’. Presumably this was a result from being in the quarry buildings where rock dust settles in thick layers.

Not having the ability to ask your ‘patient’ what the problem is makes it difficult to know how to treat. The additional problem is that any manhandling and catching of these choughs will stress them which may lead to negative associations. Much like dogs when they hear the v.e.t. word, we don’t want the choughs fearing the a.v.i.a.r.y.

Necrotic tissue visible on both feet of Green. Photo by Liz CorryAfter a day in the aviary, Green’s feathers were clean but the feet were still grey. At training he was eating with the group when called although he wasn’t as quick to get to the food as the rest. This was put down to stress but with a mind that if things didn’t improve there might be an underlying health issue. Observations on the second day showed that he was not strong when flying and often couldn’t make it from one end of the tunnel to the other without losing height and landing on the netting or the ground.

The decision was made to catch him up and upon weighing it was found that he was a good 30-40g underweight. This explained part of the weakness when flying.

Looking at his feet it was clear that the grey was not washable, it was necrotic skin most likely a result of a chemical burn. He had also suffered a chest wound at some point as there was a large scab forming.

Green was immediately put on a treatment of antibiotics to fight any infection. Medication is injected into insects which the chough will then eat. In order to ensure he would get exactly the right dose he had to be housed separate to the others for the duration of the course. He was locked into one of the sheds and given access to part of the poly-tunnel during the day.

Faecal samples were submitted to Durrell’s lab including a group sample from the females. Although with no recent clinical signs, both samples tested positive for gapeworm. This parasite is not unusual in captive birds and can also be found in the natural environment. However, the situation the Sorel choughs are in will mean their stress levels are raised and are, consequently, more susceptible to the effects of gapeworm. All the choughs immediately started a two week course of ivermectin. Unfortunately this meant catching them up to inject them and repeating it two weeks later. In turn this meant no releases could happen until the medication was finished.

Whilst this was going on Black made a surprising yet welcomed return to the aviary. She came back the day after Green had returned. In an attempt to coax her out of the quarry we had shifted the feeding site further west around the edge of the quarry. By the afternoon she had decided to return to the aviary taking a direct route along the cliff-path. Once again her body weight had changed little from when she first left.

Since re-joining the other four choughs the group dynamics have subtly changed. Without anthropomorphising too much this is no doubt related to Green’s time spent with Black as well as the loss of Orange and White. Immediately upon returning to the aviary Black stayed back from the group eating and preening and doing her own thing. Every now and then Mauve would leave Green’s side, fly at Black chasing her from her perch, then return right back to Green and preen him (a sign of pairing). With Green, now the only male, locked away, the competition for his attention has become a bit of a free-for-all.

A veterinary check-up after Green’s medication ended showed that whilst his feet were healing there was still some way to go. The most damage is around the ends of the digits leading to a small risk of losing one or two claws. A new discovery of a puncture wound on the right hock meant that the vet wanted to extend the antibiotic treatment. From assessing the scab and injury site this wound must too have occurred whilst out and about in the quarry. The next physical check-up for Green will be after the treatment has finished on 1st November. Until then he will be monitored continuously to watch how much he is eating and if he is in any discomfort.

Choughs at Durrell

This month has seen changes afoot within the breeding pairs. Arthur has taken a fancy to the juvenile female who is now coming of age. This was somewhat predictable since Arthur and Guinevere didn’t progress past nest-building this season and failed to produce a clutch last year. ‘Gwinny’ is now perching and feeding with Tristan the male who we originally paired her with in 2010. The switch to Arthur came about when the two females fought over Tristan in 2012 and Gwinny lost out to Iseult. Keepers will be observing Iseult closely now as the breeding season approaches. Along with Tristan and Arthur there is a single juvenile male in the display aviary with a claim to stake.

George weighing himself. Photo by Jessica BorerGeorge, the hand-reared chough flown over in March to assist with the reintroduction, bid his farewells this month and returned to Paradise Park. With the breeding season approaching he needed to move out of the breeding aviary he was being held in. With no alternative and no possibility of using him at Sorel, Paradise Park were asked if they could take him back. George is quite the character and will be missed by all and no doubt there will be a few holidays booked to Cornwall in the near future!

The Bird Department recently purchased new weighing scales, the same model as used at Sorel. The scales’ design makes it easier for certain species to walk or land on them. Bird staff have started training some of the captive choughs as in this way we can monitor weights and infer general body condition, without having to catch the individual and cause unnecessary stress. George was eager to show off his skills when it came to jumping on the scales. It will require a little more work with novices like Arthur and Gwinny.

Nutritional research on captive diets

Earlier this year, Iona Mucherek-Parramore spent time on the Bird Department collecting data for her MSc in Endangered Species and Conservation. Durrell has developed a close relationship over the years with Nottingham Trent University who send students here for various degree programmes. Iona’s study was looking at the nutrient profile of the chough diets at Durrell and relating it to reproductive parameters.

Choughs in captivity are provided with a breeding diet from January to August and then a general maintenance diet for the rest of the year. Birds require more protein in their diet during egg-production and chick-rearing. We cannot provide the diversity and quantity of insects choughs would need, so finely chopped ox heart is added in January to replicate this.

Iona spent eight days at Durrell collecting food samples and analysing reproductive data. On returning to Nottingham Trent she then had several weeks of lab analysis and the daunting task of dissertation writing. Her final thesis was submitted in October, a copy of which will be kept at Durrell.

The analysis brought to light a few interesting points that need addressing before the next breeding season as they may be influencing egg productivity and survival rates. For example there appears to be no difference in calcium provision between the two diets. Extra calcium is added for the breeding season using grated cuttlefish bone. However, other ingredients are reduced which also contain calcium thereby negating the impact of the cuttlefish bone. Also, the fat content year-round is much higher than one would expect for birds. It should be noted though that there is no published data available for choughs to allow a definitive comparison.

November volunteer activity

Sunday 3rd November – Noirmont Common – 10.30am to 13.00pm

Tackle the scrub advancing onto the small patch of Common toadflax.

From Jersey Conservation Volunteers

November’s Volunteer task will be on the first Sunday of the month rather than the normal second Sunday. This is to avoid the clash with Remembrance Sunday.

Vounteers at Noirmont. Photo by National Trust for Jersey

Meet at Noirmont Common SSI car park at the end of the headland (Jersey phone directory map 7, D5, at the southern end of Chemin de Noirmont). Please let us know if you need further directions

Noirmont Common is a Site of Special Interest on the south-west coast. Our regular volunteers will know it quite well!

Common toadflax. Photo by Alistair BaxterCommon toadflax Linaria vulgaris is a Biodiversity Action Plan Species with a ‘locally scarce’ status. It’s habitat is grassy banks and fields and, therefore, one of the reasons behind this species’ decline in recent years is harsh branchage methods, cutting before the plant has finished flowering, and not removing the cut vegetation. There is a small but thriving area of common toadflax at Noirmont which we are trying to encourage to spread; however, we need to tackle the relentless march of scrub which surrounds the patch and threatens it.

As always, some tools will be supplied, but you are welcome to bring your own if you have them. Cutting tools such as sickles, secateurs and loppers will all be useful as well as rakes.

Good thick gloves (though again we will supply a pair if you don’t have them), sturdy boots and common sense clothes to cope with the elements are recommended.

Children are welcome to attend this task as long as they are directly supervised by a parent or guardian.

Kim ‘the cake’ Koester will be on hand to dish out coffee/tea and cake at the end of the task.

Hope you can make it!

Latest news….Jersey Conservation Volunteers now have a Facebook page where you can keep up with the latest news and events, and post photos from the tasks (many thanks to the National Trust’s Sally for setting it up). Please visit and ‘like’ them at https://m.facebook.com/profile.php?id=309170622555799

Common toadflax. Photo by Sally Dalman

 

Birds On The Edge Autumn Walk – with the National Trust for Jersey

Date: Saturday 16th November
Start: 10.30am
Venue: Devil’s Hole
Duration: Approximately 2 hours

Join Birds On The Edge and The National Trust for Jersey on a tour of this year’s BOTE achievements as we walk along the north coast path from Devil’s Hole to Sorel Point.

Spring walk 2013. National Trust for JerseyFollowing up the very successful Spring Walk, now we have a chance to catch up with the project’s latest news and witness the progress made. We will see the grazing herd of Manx Loaghtan sheep, the bracken clearance works and the conservation fields that are in full bloom to feed our local birds throughout the winter. We hope to see the chaffinches, linnets, goldfinches, skylarks and song thrushes amongst other birds feeding in the conservation crops and learn about the findings of the north coast breeding survey that was carried out in the spring.

While we are on the cliffs we will look out for the choughs and learn how the programme to return these stunning birds to the Island is progressing. We can see the release aviary and get the latest update.

Spring walk 2013. National Trust for JerseyThe walk will last approximately two hours, on undulating terrain, so good shoes are required and a degree of fitness. Bring weatherproof clothing and drinks as, you never know, it might be warm! There will be a pub on hand for lunch later if you choose!

Please meet in the Upper Car Park (above the Priory Inn) at 10.15.

Chough report: September 2013

Black in Ronez Quarry 26-9-2013. Photo by Romano da Costa By Liz Corry

Sorel Choughs

Liz Corry locking hatches at release aviary. Photo by Rick JonesWith the second release at the end of August seeing Green and Mauve flying off to the quarry, September turned out to be a very busy month. After two days of living around the north edge of the quarry, the pair started to explore the coastline eastwards. The blanket covering of bracken heading off to Bonne Nuit was probably the reason they decided to turn back almost immediately and look for foraging sites around Ronez Point. Potential sites are limited in that area but thanks to their training in the aviary and the continuous monitoring by staff they were able to find food.

Using a moveable target board, placed in clear view and on ground where the choughs can land, the birds were lured down for mealworms. Very quickly the pair remembered that on hearing a whistle their keeper would be bringing food. By the second day of supplementary feeding the tracking sessions had turned into feeding sessions with the birds appearing like clockwork.

Choughs weighing themselves on scales in aviary. Photo by Liz CorryFor reasons known only to them, the pair decided to travel west in the afternoon four days after leaving the aviary. They arrived back at the aviary in the late afternoon much to the delight of the rest of the group and the team. The chough pair didn’t need much encouragement to go back inside the aviary. On cue with whistle and food they flew through the open hatches and joined the others.

The next morning Liz was able to get weights from all of the choughs landing on the scales. Green and Mauve had lost a bit of weight from being out but nothing alarming. Naturally they would have burned more calories flying around exploring the quarry and food would be limited compared to that available at the aviary. Providing the birds with supplementary insects whilst out, no doubt kept their body weight at an acceptable level.

Thick fog led to a few days delay until the next release. This was more eventful than the last due to couple of factors out of the team’s control…weather and uninvited ‘visitors’. All seven choughs ventured outside this time and settled quite happily on the ground in front of the aviary probing for insects. Before it was time to call them back, their attention had been diverted to a flock of 30 carrion crows heading inland from the cliff path. The choughs took to the air with great intrigue and circled with the crows for a few minutes. Curiosity satisfied, the crows departed with the choughs heading towards Mourier Valley. Liz tried to call them back but by this stage they were no doubt overwhelmed. In panic the group began to split up with a pair heading over to Devil’s Hole and one bird flying inland towards the farm. All this was being hampered by the onset of a really heavy downpour forcing the birds to find shelter.

Ronez Quarry provides shelter and roost sites for choughs as well as fresh water. Food resources are also likely but not in abundance. Photo by Liz CorryBy sunset three birds (Green, Mauve, and Red) had returned to the aviary. Interestingly these were the only three that had previous experience of having to find a roost outside of the aviary. An example of learning by trial and error maybe? Visibility in low light and rain meant the remaining four could only be located via their radio signals. Two were thought to be in the adjacent fields to the aviary whilst two others were near the dirt bike track.

Upon returning at 06.00 the next day the four were visually located and then followed throughout the day. Very early on Orange, Black, and Blue met up in the quarry. White was also in the quarry but for some reason keeping separate. By the afternoon all four were together foraging around the south side. Unlike the pair that had previously spent time in the quarry these four roosted outside on the rock face.

In light of previous activity, the plan was to keep the three aviary birds locked in acting as call birds and monitor the four outside under the assumption they would return to the aviary. After six days out there was concern that these birds had different intentions. Attempts were made to supplementary feed, but with location and wind conditions they were not very successful. On the evening of the 12th insects were left out in an area the choughs might naturally forage but had not been seen in before. The team were pleased to see the chough there the next morning so the process was repeated. Unfortunately this week appeared to coincide with the departure of summer. Horizontal winds and rain prevented insects from being thrown into the quarry. This probably also forced the birds to stay in the quarry where they knew they could find shelter.

Chough eating mealworms thrown in by team. Photo by Liz CorryOn the 18th radio trackers were picking up a stationary signal from Orange away from the other three choughs. Bad weather the day before meant that simple visuals on all four birds were not possible in the afternoon. Only two choughs could be seen on the morning of the 18th. The signal from the third implied it was with them, but with lots of hiding places and tall vegetation seeing the colour rings was near impossible. With no change by the afternoon the radio trackers were obviously concerned and approached the management of Ronez Quarry to request permission to search lower levels. Unbeknown to the team, Ronez were trying to contact them at the same time. Sadly workers down on the floor of the quarry had found a recently dead chough and had brought it back up to the offices to return to Durrell.

To the surprise of the team the body recovered was that of White and not Orange. It seems that the movement of White’s signal in the afternoon was a result of her being driven out of the quarry in a company vehicle. The body was taken straight to Durrell’s Veterinary Department where a full post mortem was carried out. The cause of death was recorded as starvation. Although internal parasites were found, it is thought that these were secondary and not the underlying cause of death.

The tracking team was granted permission to enter the quarry under the supervision of Kirsten du Heaume, Operations Manager. Several attempts were made to isolate the signal. The search was hampered by signal bounce from the granite rock and health and safety concerns which prohibited access to certain levels. Kirsten kindly searched a few areas not usually accessed, but with no success. As frustrating as it is, nothing more could be done. The signal location remained unchanged for a week and with no sighting of a third chough, Orange was disappointingly declared deceased.

Blue and Black in the meantime were flying strongly, avoiding the peregrines, and ironically once again taking supplementary feed the day White was found dead. Using a catapult, the insects could be thrown against the wind and reach levels the team could not. The two female choughs settled into a pattern of flying to the supplementary feeding site when called and appeared to not have any reason to leave the quarry.

The release process was restarted on the 23rd with the three in the aviary. If Green and Mauve did return to the quarry they would hopefully meet up with Blue and Black and lead them back to the aviary. Red, now a single female with the loss of Orange, would presumably fly with them in fear of being left behind.

This time, however, the birds didn’t leave the aviary field. They made several short flights from target sites to perching points along the hedgerow erected by the keeper. Having high places to land near the aviary allowed the birds to feel more secure and take time to assess their surroundings. All three returned on call and were locked in the aviary overnight. The next day was very different. The pair exited the aviary within 53 seconds of the hatches being opened, took to the sky and flew straight back to the quarry. Leaving a rather confused Red behind in the aviary.

houghs living in the quarry are not always the easiest to see. Photo by Liz CorryAs the pair flew over Ronez Point an attempt was made to call them down for supplementary feed. Blue and Black flew up from the quarry and took to the challenge readily. Green and Mauve flew over calling, but then headed away and over to Sorel point. After feeding, Blue and Black headed back into the quarry. However, for reasons only known to a chough, Blue decided to continue flying and minutes later landed on the roof of the aviary. After 18 Choughs living in the quarry are not always the easiest to see. View through Neil's telescope. Photo by Liz Corrynights of roosting in the quarry and to the delight of Red, Blue spent the night in the aviary.

At the morning’s weigh-in session, Blue was found to be the same weight as when she first left: once again showing the necessity of supplementary feeding if the birds choose to live in the quarry. As Liz was packing away the scales, Green and Mauve landed on the aviary. Like a well-rehearsed routine, the pair walked back into the aviary where they joined the others.

The next release, on the 26th, was somewhat more predictable with the exception of the gunshots coming from the fields inland. Each time a shot was fired the birds would fly up from the ground to a perch and/or shelf. At the same time that the decision was made to call the birds back before they got too upset, the pair decided it was time to leave. They circled the aviary a couple of times before heading straight back to the quarry. Despite their calls being audible to onlookers neither Black nor the pair made an attempt to meet up.

With all the choughs in the aviary, Black has to make new alliances beginning with a friendly game of hide and seek. Photo 1 by Liz Corry

With all the choughs in the aviary, Black has to make new alliances beginning with a friendly game of hide and seek. Photo 1 by Liz Corry

With all the choughs in the aviary, Black has to make new alliances beginning with a friendly game of hide and seek. Photo 2 by Liz Corry

By the end of the month Black had settled into her routine of meeting the team for food and roosting on the quarry face. Green and Mauve happily roost in the quarry buildings, but return to the aviary for food. Blue and Red appear nonplussed by the absence of the others and continue as normal in the aviary.

 

 

Wild bird populations in UK continue to decline

From The Guardian

Linnet. Photo by Mick DrydenThe number of wild birds in the UK is still falling, despite efforts to protect them by changing farming practices.

Since 2003, there has been a 13% decline in the population of farmland birds. In the five years to the end of 2012, the decline was 8% overall. The decline has slowed, according to the Wild Bird Indicator statistics released by the UK Government, and some species are in better health than they were in the 1970s when data began to be comprehensively collected. However, conservationists are concerned that the drop in numbers is continuing, with a halving of farmland bird numbers in the past 40 years. Woodland birds are down 17%.

Turtle doves have had their lowest level of sightings since records began. Lapwings are down by nearly two thirds since 1970, while corn buntings are down nine-tenths in the same period, and the number of skylarks is down by well over half.

Farmland birds suffer from intensive agriculture, as farmers often remove or drastically cut back the hedges and trees where many of them live, while pesticides can leave them with less prey, and a lack of wild field margins cuts down on habitats.

UK’s breeding farmland bird populations 1970-2012. Table from Defra’s Wild Bird Populations In The UK, 1970 To 2012There are some government-sponsored schemes to encourage farmers to make room for wildlife, for instance by leaving field margins wild, cutting down on pesticide and artificial fertiliser use, and leaving some areas fallow or pasture. There are also strict laws against killing rare birds of prey, but conservationists think these are frequently flouted.

Martin Harper, conservation director at the RSPB, said: “The trend for farmland birds continues to go downwards. The decline has slowed, and wildlife friendly farmers who put conservation measures in place on their land must be congratulated for their hard work. But if we are all going to work together to bring wildlife back to our countryside, then the funding must be there for these measures to continue.”

Under reforms to the common agricultural policy, which were agreed this summer, the UK Government has the ability to divert some of the millions of pounds of funds available – which come ultimately from European taxpayers – to environmental stewardship schemes to reward farmers for good practice.

The UK Government, has still not said how they might allocate the funding, which could go up to 15% of the agricultural subsidies budget. But given the government’s freedom of action under the new rules, much of it could go to farmers based not on their practices but on the amount of land they farm, as other subsidies are.

A decision is expected before the end of the year, and green groups are concerned that the amount devoted to environmental measures will not be enough to halt further declines in wildlife numbers.

The situation in Jersey appears very similar and Birds On The Edge is working with our local farmers to monitor locally endangered birds and enhance the habitats of their farmland via a sponsored trial scheme. Some of the fields in the north coast have been planted with hedges and the fields have been sown with conservation crops that are providing birds with a source of food throughout the winter. The public will hopefully be able to see these fields and the birds feeding on them on the Birds On The Edge Autumn Walk – details to be announced soon.

The full UK report Wild Bird Populations in the UK, 1970 To 2012 can be downloaded in full here

Conservation crop in field on Jersey's north coast. Photo by Cris Sellares

PIB discharge at sea BANNED!

Alderney Wildlife TrustFrom Alderney Wildlife Trust

Following action by The Wildlife Trusts, RSPB and RSPCA the International Maritime Organisation (IMO) decided to reclassify Polyisobutelene (PIB), under the International Convention for the Prevention of Pollution from Ships (MARPOL), making it illegal to discharge any amount into the sea.

The IMO is stopping ships from discharging PIB at sea after birds covered in the sticky substance were washed up on the Channel coastline. Over 4,000 seabirds washed ashore, dead or dying between February and May, after there were two separate spills. The substance which has been likened to PVA glue in consistency, coats the birds feathers, rendering them unable to fly or maintain core body temperature.

The tragedy, the largest marine pollution incident of its kind in the region since Torrey Canyon, shocked thousands of people. At a meeting of the IMO’s working group on the Evaluation of Safety and Pollution Hazards of Chemicals (ESPH), it was decided to change the classification of high viscosity PIBs and prohibit any discharge at sea from 2014. This will also apply to new “highly-reactive” forms of PIB, which are currently being transported un-assessed.

The recommendation to do this had been made by the Maritime and Coastguard Agency (MCA) on behalf of the UK Government, following vigorous campaigning by wildlife charities and the public.

This was a decision which was expected to take years and the efforts of all those who lobbied so hard in the Channel Islands should not be forgotten.

Thanks go out to GSPCA, JSPCA, Durrell,  La Société Guernesiaise,  La Société Jersiaise and the National Trust for Jersey who joined the AWT campaign and all of their Facebook and Twitter followers! The Birds On The Edge report can be read here.

Today’s decision is a real step forward, safeguarding our seas and sealife for future generations.Razorbill. Photo by Mick Dryden

 

How many birds die each year in human-related ways?

Hen harrier and hazards. Photo by Mick DrydenFrom BirdLife International

It is becoming increasingly obvious that our already declining bird populations, threatened by widescale habitat and climate changes, are put under further pressure through the actions of humans. Scientists with Environment Canada have found that human-related activities destroy roughly 269 million birds and 2 million bird nests in Canada each year. Most human-related bird deaths (about 99%) are caused by impacts of feral and pet cats, and collisions with buildings, vehicles, and electricity transmission and distribution lines.

Over the last four years, 20 Canadian scientists conducted extensive analyses that enabled them to release the first-ever estimates of annual direct bird mortality from human-related sources. The results have just been published in a special issue of Avian Conservation and Ecology.

“Because birds are excellent indicators of biodiversity, the newly-released articles from Environment Canada highlight areas where broader biodiversity may be impacted”, said Dr George Finney, President of Bird Studies Canada. “These results provide a crucial first step toward understanding the relative importance of bird mortality factors, and will inform future research directions, conservation actions, and policy decisions.”

Feral cat. Photo by Stephen PiggottCats appear to kill as many birds as all other sources combined. Feral and pet cats are believed to kill more than 100 million birds per year in Canada. An estimated 60% of those are killed by feral cats. Bird species that nest or feed on or near the ground are especially vulnerable to cat predation.

“We are deeply troubled by the disquieting research published today on the number of birds killed every year in Canada due to human-related activities”, said Ian Davidson, Executive Director of Nature Canada. “Fortunately, there are concrete and sensible ways that people and governments can prevent the needless death of birds, especially now during the migratory season.”

Collisions with electricity transmission and distribution lines have been identified as the second-largest human-caused source of bird mortality in Canada. Between 10-41 million birds per year are killed by collisions with transmission lines; between 160,000 and 800,000 birds are electrocuted by distribution lines; and about 400,000 nests are destroyed annually due to vegetation clearing under powerlines.

Grey heron. Photo by Mick DrydenCollisions with residential and commercial buildings are the third-highest of the human-related sectors, killing an estimated 16-42 million birds each year – mostly at houses. Following bird-friendly building guidelines can help individuals and building managers reduce the risk to birds. Using commercial products, special glass, or homemade solutions to make windows more visible to birds can reduce daytime collisions. Night-time window collisions can be reduced by leaving lights off in low-rise and high-rise buildings.

An estimated 13.8 million birds are killed annually by colliding with vehicles on Canada’s primary and secondary roads.

There are about 10 billion birds in Canada. The estimated total of 269 million bird deaths per year caused by human-related factors constitutes less than 5% of the overall population. Bird deaths from other causes (such as natural predation, disease, severe weather, or habitat loss) are not reflected in the estimates.

Whilst Canada is undoubtedly a very large country we can still see that the Channel Islands will contribute annually to the global, and un-estimated, man-made, and avoidable, toll of wild birds. We are increasingly beginning to realise how important our islands are too for migratory birds just passing through. How many each year fail to reach their destination through some man-made structure in their path that they don’t see? Or from the house cats and feral cats that are found everywhere in Jersey except on our offshore reefs – and even there birds aren’t safe from man-made problems! And, when thinking of feral cats, is it any wonder why we have so few lizards in some places!

Barn swallow. Photo by Mick Dryden. Many thousands fly through Jersey each year

Chough report: August 2013

Maiden flight of green. Photo by Annette LoweBy Liz Corry

Radio transmitters and veterinary health checks

The four remaining birds without transmitters were caught up on the 20th to have new transmitters attached. In the process the other three were also caught to check there were no issues with their new transmitters.

None of the choughs had completed their moult. However, they are at a very advanced stage and therefore fine for a release. It was noted that a knot was loose on a couple of transmitters that had been fitted last month. This was not deemed a huge concern since they are attached in other places including the transmitter being glued to the feather shaft.

Habitat management

Sheep at Sorel. August 2013. Photo by Liz Corry This month the National Trust began treating designated areas of bracken with an herbicide as part of their removal programme. Asulox was applied using a hand sprayer. As a safety precaution all the sheep were temporarily removed from the cliffs and housed in the aviary field for four weeks.

The choughs did not seem to mind having new neighbours. In fact it probably provided a novel form of enrichment. Choughs and sheep at Sorel. August 2013. Photo by Liz CorryThe sheep were moved back out before the end of the month.

Soft release underway

The soft release phase began at the end of August (report). The first day went better than imagined with three birds venturing outside. Albeit on the shelving around the aviary. Green (PG) had the honour of taking the maiden flight onto the roof of the aviary and around the tops of the hedges, but didn’t go far. When it came to calling them back after 30 minutes the whole group flew down to the shed end for the food. Green was faced with the dilemma of how to get through roof netting to reach the food. After a quick brainstorming session he remembered where the hatches were and flew back in.

The second night was similar in that three ventured outside this time being a bit more adventurous. When it came time to call them back the three were on the roof of the shed. Eager to get to food two of them worked out straight away where to go. Red (RD), on the other hand, was completely baffled and spent the next two hours trying to figure out how to get in. Her dilemma was twofold: how to get to the food through netting?; how to get to the food without leaving her partner, Orange (OR), who was locked in the shed? She ended up spending the night on the roof. At 6am when keepers returned she was still perplexed. By 9am she had been coaxed inside by giving the birds in the aviary access to the whole polytunnel. As they flew to the end where the hatches are she followed. After a few minutes of letting her familiarise herself with the shelving the aviary birds were shuffled back and the hatches were opened.

As this is a pilot study Red’s experience has provided an opportunity to learn and improve. Roosting boxes have now been added outside the aviary in case a bird repeats her experience. This might also act as another anchor for keeping the birds close to the aviary and reduce the need to search for roost sites further away.

 

 

 

Chough update: setbacks and personal agendas

Chough looking for food at Ronez Quarry. Photo by Liz CorryBy Liz Corry

Setbacks

On 6th September things changed and, with the Ronez 2 pair back we had four other birds living in the quarry instead. Now, with four different, and very individual, birds out we had to learn again how to find each one. Several times a day. We managed to get some insects to all four birds by the next weekend but the wind and rain made it impossible to get adequate supplies down onto the ledges (think mealworms flying backwards over your head). On the 18th we became very worried about OR as his signal suggested that he was no longer moving and had been in the same spot for a while. However, very sadly, while trying to pinpoint his exact whereabouts in a difficult area within the quarry, a second bird (WT) was collected freshly dead by Ronez personnel from the floor of the quarry. Gross post mortem results seem to point at starvation. This was very worrying as we were seeing the birds foraging, suggesting that either they can’t find anything suitable to eat or that they are very naïve in their foraging (we do not know how much food is even available as we cannot safely access the foraging sites).

Chough looking for food at Ronez Quarry. Photo by Liz CorryImmediately after the sad discovery of WT we watched the two surviving quarry birds (DB and BK) actively foraging but also flying around well, calling and looking fit and healthy. We accompanied the quarry manager in a further, thorough, attempt to locate OR but although we could get within a few metres it was unsafe to get right into the probable site we were getting a signal from. This meant we had effectively to write off OR as lack of any movement after more than two days could only really mean one thing. Losses like this, while upsetting to all involved, add to our understanding in this project and in fine-tuning the release. We always knew, and were pre-warned by colleagues who have led very successful release projects of this nature, that there would be losses along the way. As you can imagine though, the knowledge that losing some birds was inevitable did little to soften the blow.

DB and BK continued to look good, looked fit and active and must have been getting at least some food. We gained too in confidence that as they settled into a routine we could supplement their food in the quarry more. On the 21st, with an anglers’ catapult, we got insects down to the two choughs where they were and from there on they seemed to remember their training. Within a couple of days the two were hopping over the quarry fence to Ronez Point when called and getting plenty of food, and plenty of attention!Choughs at Ronez Point. Photo by Liz Corry

Choughs: birds with their own agenda

Meanwhile, back in the aviary the birds were fine and continuing to respond well to the whistle. We went back to the release plans for these three birds and once again it seems that they themselves are working to their own, well planned, agenda. On the 23rd the three choughs went out and safely came back on call. Then, the following day as the hatches were opened, MV and PG, the Ronez 2, without any hesitation, not even bothering to look around, flew straight to the quarry, passing DB and BK as they went in. They had to have planned that one! That night they once again slept in the conveyor (DB and BK have slept each night on the quarry cliffs).

Choughs at Ronez Point. Photo by Liz CorryAnd………. As if the personal plans of the Ronez 2 weren’t enough to be getting on with, as I returned to the aviary to say goodnight to RD who had decided to stay indoors, DB was there waiting for me! She went straight in and joined RD after 18 nights away! BK, however, spent the night alone in the quarry.

What will they do next?

We woke, worried about how BK was faring alone but she quickly came for food. Back at the aviary, DB weighed herself on the scales and could be seen to be at her normal weight. The Ronez 2 pair flew around a bit, ignored BK, and went back to the aviary and let themselves in. This is pretty well what they were meant to do, to go out, explore, learn about the wild and come back to the aviary for security and food while they adapt to freedom. We just wish they would all do it at the same!

Lessons learned

Choughs at Ronez Point. Photo by Liz CorryWe always knew that there would be setbacks; this is a trial, a pilot study, because no one really knew how captive-reared choughs would adapt to the wild. It is becoming apparent that individual birds all have their own characters and this individuality may be the very key to their survival chances. So, while there have been some very sad and dispiriting days, we will continue with the momentum of this trial. The sight of these beautiful birds, and the interest and excitement being generated by their release, is so very encouraging.

 

Further woe for turtle doves

Turtle dove in St Ouen's Bay. Photo by Miranda Collett

From British Ornithologists’ Union

Can things get worse for turtle doves in northern Europe (for example, if you can’t shoot them at home, shoot them on holiday)? Possibly, for the first time anyone knows, none nested in Jersey this year when only 20 years ago they were common in places and their purring was a well-known summer sound. To understand what may be behind this region-wide decline, all aspects of the species’ ecology are being investigated, including the effects of disease. See updates on this beautiful bird through Operation Turtle Dove.

Very little is known about some of the potential problems facing turtle doves on their breeding grounds in Europe, their wintering grounds in Africa and their migration routes. But could disease be an additional problem for this fast-declining bird?

Scientists from the University of Leeds, along with the RSPB, have been working on this and recently published a paper

Turtle dove. Photo by Mick DrydenColumbidae (doves and pigeons) appear to be more susceptible to some diseases than other species, and being gregarious, the transmission of disease can easily spread from one bird to another. Trichomoniasis is a disease commonly found in Columbidae and is caused by the Trichomonas gallinae parasite. It is known to be a problem for the endangered Mauritius pink pigeon for example, where it can result in high mortality in young pigeons in the nest. It has recently been found in greenfinches, passed on via infected garden bird feeders, and led to a 35% decline in greenfinch numbers within a year in the UK (see BOTE reports here and here).

The joint study aimed to establish whether the parasite was present in wild turtle doves, as well as in three other related species – collared doves, woodpigeons and stock doves. It also aimed to understand the disease better and find out whether the parasite found in doves and pigeons is the same strain as that killing greenfinches.

The team found the parasite present in all four pigeon and dove species, but turtle doves and collared doves were the most likely to carry the parasite with 86% being infected. This was the first time that the parasite has been confirmed in turtle doves in the UK. Unlike the other Columbidae studied, turtle doves rely on seed food all year and they are a migratory species. Increased agricultural efficiency has reduced the availability of arable weed seeds during the period when turtle doves migrate back to Europe from Africa and it is possible that this food stress makes them more susceptible to disease.

Turtle dove. Photo by Romano da CostaOn farms where supplementary food was put out for game birds, more of the doves and pigeons were found to have the parasite. This suggests that in a similar way to the disease being passed between greenfinches on garden feeders, the parasite can be passed between wild birds on farms. This is likely to be due to a food source, whether supplementary feeding or accidental spillages, attracting a lot of birds to the same place, meaning it is easier for the parasite to pass between birds of different species. Of the birds that were shown to have the parasite, hardly any were showing clinical signs of the disease, such as saliva round the beak, so it is unclear what effect, if any, this parasite is actually having.

Four strains of this parasite were identified, but more work is needed to find out whether any of these are identical to the strain killing greenfinches. Overall, as well as providing the first evidence of the extent of infection in turtle doves in the UK, this work also highlights the need to understand the effects and implications of Trichomonas parasites on the host bird.

This work was jointly funded by the RSPB and Natural England through the Action for Birds in England Partnership.