Migrating birds might not be able to fly home fast enough to meet shifts in springtime

Willow warbler. Photo by Mick DrydenFrom Carbon Brief

Flying back too early or too late for spring is costly for migratory birds. Their arrival must coincide with the emergence of food sources, such as caterpillars, in order to enable them to feed and successfully rear their young.

Birds that overwinter in warmer climes, including willow warbler, tree pipit and barn swallow, will be unable to cut their migrations short as climate change causes spring to arrive earlier in many parts of Europe, as new evidence suggests that some birds are much less adaptable to climate change than previously hoped.

Tree pipit. Photo by Mick Dryden

Time to fly

Each winter, around half of the UK’s birds take off to find food in a more temperate climate, returning to their ancestral breeding grounds the following spring. However, scientists fear that this annual migration could be disrupted by climate change, which is causing spring to arrive six-to-eight days earlier in Europe than it did 30 years ago.

Evidence suggests that some birds will be able to adapt by leaving for their winter grounds later in the year or wintering closer to home (see BOTE report here). However, not all birds are able to perceive subtle shifts in temperature and instead rely on the number of daylight hours – which is unaffected by warming – to tell them when it’s time to fly.

For these birds, keeping pace with an earlier spring means getting back from their wintering grounds more quickly. But the solution isn’t as simple as flying at a faster speed because birds simply do not have the energy to beat their wings any harder during their lengthy migrations. A new study, published in Nature Climate Change, looks at a third option: reducing the length of “stopovers”. These are the avian version of a pit stop, where birds feed and rest before continuing their journey. While shorter stopovers can significantly speed up a migration, it’s unlikely to be enough, the study finds.

For example, cutting time spent resting by 50% would lead to birds arriving in their spring grounds just two days earlier, on average. In comparison, the peak availability of caterpillars – a key source of food for birds – in UK forests advanced by 20 days between 1980 and 2008. This mismatch between the arrival time of birds and their foods could spell trouble for many bird species that are unable to adjust the start of their spring migration, says lead author Dr Heiko Schmaljohann from the Institute of Avian Research in Germany:

“The inability to sufficiently adjust or adapt the breeding area arrival timing leads to an increasing mismatch between food availability and its demand. If this mismatch increases for a species population, it is possible that this may lead to a population decline.”

Schmaljohann adds that although there are some birds which seem to be adjusting their spring arrival date in response to climate change, such as the pied flycatcher, it is still not known which species are most at risk of decline:

“The pied flycatcher has advanced its breeding area arrival timing the most. Whether they have a better ability of detecting how conditions will be at the breeding area in one to two months is totally unknown. It is extremely unlikely that birds, being still at their African wintering grounds, can anticipate the environmental conditions they will experience at the breeding areas in advance.”

Pied flycatcher. Photo by Regis Perdriat

Calculating migration speed

To understand what drives the speed of a migration, the researchers reviewed data from 49 tracking studies of 46 different bird species.

They found that the overall migration speed is largely dependent on the number of stopovers, which they defined as spending more than one day in the same location. Researchers then used mathematical modelling to predict how reducing the amount of time resting while flying home could help birds to speed up.

Their modelling considered the average flying speed, the total migration distance and how birds can vary their speed in response to changing environmental conditions. In the future, birds may actually be forced to take longer breaks as their stopover grounds will likely be affected by climate change, says Dr Schmaljohann:

“When birds experience unfavourable conditions, such as drought, heavy rain and cold temperatures, the feeding conditions deteriorate. The feeding conditions directly affect total speed of migration via stopover duration.”

Adapting on the fly

This new research may help to explain why birds appear increasingly unable to keep pace with climate change, says Dr Stephen Mayor, an ecologist from the University of Florida, who wasn’t involved in the study:

“You would think that birds which migrate thousands of kilometres with the changing seasons would be experts at adapting to climate change, but this evidence suggests birds are much less adaptable than we might hope – probably because the climatic changes are so rapid and variable.”

The full paper The limits of modifying migration speed to adjust to climate change, Nature Climate Change can be seen here

 

Barn swallow (2). Photo by Mick Dryden

Chough report: August 2017

by Liz Corry

This month has flown by. So have the choughs. Awful opening line, but accurate. Now that the breeding season is over the choughs are spending more time away from Sorel and it is quite rare to see all 38 choughs at the supplemental feeds.

West is best?

Lee and Caûvette are back at Les Landes and Grosnez. This time with their chick in tow. We were treated to several sightings of the family whilst we carried out rat monitoring fieldwork at Plémont. The most memorable sighting was that of all three flying through the early morning fog towards Grosnez. These days they spend the whole day out west, returning to Sorel an hour or so before roosting time.

Lee photographed by a member of the public at Grosnez castle. Photo by Mike Nuttall.

They are not the only ones on the move. A sighting from an ex-Durrell colleague of seven choughs flying over Hamptonne Country Life Museum added to the tally of sightings in St Lawrence parish.

All of the reports from St Lawrence are of birds flying over. Are the choughs just passing through or checking out the parish for suitable feeding site?

Their daily activities are making it a little harder for the team to monitor every chough as closely as we have in the past. Although we have still kept on top of monitoring their health and welfare. It is hard not to when you can get this close…

Syngamus infections in the wild chicks

Last month we reported that the wild chicks were sneezing and sounding congested. We managed to obtain individual faecal samples for three of the four chicks after patiently waiting at each feed. All three tested positive for syngamus nematodes. The fourth bird is proving harder to sample as it disappears out west with it’s parents each morning.

We have so far managed to trap and treat two of the chicks. We are still trying with the third. The chick we treated in July has shown a great deal of improvement which is encouraging.

Durrell vet nurse, Teresea Bell, examining one of this year’s wild chicks. Photo by Liz Corry.

Perils of living in the wild

One of the wild chicks had to be caught up for a second time this month. Beanie baby had plastic thread entangled around her foot. It was quite a mess and needed cutting. Luckily there was no damage and she was free to rejoin her parents. The other good news is that she had put on weight since the last catch-up to treat her for syngamus. We can’t hear her wheezing or sneezing anymore suggesting that the treatment has worked.

Plastic sack thread entangled around the foot of one of the wild chicks. Cut loose prior to photo being taken by Liz Corry.

Upholding tradition

We received report this month from a family who live close to the release site. They were pleased to see three choughs chilling out on their roof taking in the local scenery. We see a similar sight at Crabbé on the granite farmhouse and in Mourier Valley.

What is particular nice about this photo is the choughs sat on the witches’ step, or pièrres dé chorchièrs in Jèrriais. These are flat stones jutting from chimneys of granite houses in Jersey. According to Channel Island folklore, these small ledges were used by witches to rest on as they fly to their sabbats, i.e. meetings. In doing so the homeowner would be looked on favourably by the witch. One witch, Marie Pipet, from Guernsey was said to possess the power to turn herself into a chough!

Enrichment ideas for the captive choughs

Gianna 8-2017

Project student John Harding was set the task of designing enrichment feeders for the choughs in the zoo. Gianna, the tame chough, took up the role of R&D assistant and put them to test. She probably did more eating than assisting, but it still helped John find a winning design.

He also learnt a great deal as he discovered that ‘product placement’ is just as important as design. There are certain areas within the aviary, mainly on the ground, that Gianna does not like going to. In some cases it was a matter of gaining her confidence. In others she just outright refused to go and therefore a waste of time putting enrichment there.

Saving the devil: a story about seabird recovery in the Caribbean

by Liz Corry

Last Thursday, Dr Kirsty Swinnerton gave a talk at Jersey Zoo about seabird recovery work in the Caribbean, Alaska and the UK, to name a few. Kirsty demonstrated how the problems (pests) and recovery actions (pest management, social attraction, nest-boxes) are the same in the different regions for different seabirds. Also, how we can exchange ideas and lessons learned across species, organisations and regions.

Dr Kirsty Swinnerton presenting at Jersey Zoo to a packed out auditorium. Photo by Liz Corry.

The talk was very well attended and received a lot of positive feedback. We hope to publish a summary on the website in the next few weeks. Kirsty ran out of time to show the film trailer for one of the projects she mentioned, Saving the devil.

For those of you unable to attend the talk, put the crucifixes down and let me explain. The ‘little devil’, or Diablotin, to residents of Haiti, is a black-capped petrel. A secretive, unassuming seabird that just so happens to fly at night making sinister ghostly calls, hence the name.

A black-capped petrel with Adam C. Brown a scientist studying the species. Photo credit BirdsCaribbean.

The black-capped petrel was thought to be extinct, thanks to human encroachment and introduced predators, namely mongoose. It was rediscovered in the 1960s in a remote part of Haiti. The species is considered an indicator of how healthy Haiti’s habitat is. With only three breeding sites across the entire country the answer is clearly not a positive one.

Thanks to considerable research and conservation management, by scientists and local NGOs, the outlook is starting to look better.  Research techniques which could be applied here in Jersey, include the use of marine radar technology and night vision binoculars. The petrel comes to shore only for a few months of the year to breed; flying into forested mountains at night to underground burrows. This technology allows biologists to locate, identify and count flying petrels coming inland, in the dark. It has led to the petrels rediscovery a few years ago in Dominica, West Indies.

You can learn more about the petrel and the project by clicking here. The three minute trailer for the film ‘Saving the devil’ is below. The full length film will no doubt be saddening and thought provoking, but ultimately an example of conservation optimism and how we can make a difference.

Trailer for “SAVE THE DEVIL”, a documentary about the story of two families fighting for their life in Haiti. from Guido Ronge on Vimeo.

Chough report: July 2017

One of this year’s wild-hatched chicks arriving at the aviary. Photo by Liz Corry.

By Liz Corry

Fledging news!

Previously on Choughs…cue theme music…On 27th June Beanie baby was the first of four wild chicks to appear at the aviary with parents, Kevin and Bean, by its side.

Six days later another chick arrived. Unringed, but accompanied by Green and Black, and sneezing and wheezing, so it wasn’t hard to determine which nest it came from. It wasn’t hard to find a name for the new chick either. Lil’ Wheezy, who clearly wasn’t well, but it had made it to the aviary, so it’s odds were looking up.

A wild-hatched chick arrives for the first time at the aviary with parents begging for food. Photo by Tanith Hackney-Huck.

The third chick made an appearance on 5th July. We knew which nest it came from because of we could see pink and black leg rings. We didn’t know who it’s parents were. Well, not until it started guzzling food down its throat provided by Lee and Caûvette. This meant that our Les Landes pair had been travelling 9km away from their nest and the group finding food for their chick.

The news of this chick also means that another of our four hand-reared choughs has successfully bred in the wild; Dingle (fathered two in 2016), Caûvette and Bean. Poor Chick-Ay has yet to find a dedicated partner.

The fourth and final chick was spotted flying around the quarry on 6th July. Again, we knew which nest it was from, but did not know the parents. Two days later we were in for a pleasant surprise. Q and Flieur, a new pairing, led their chick over Sorel Point to join the flock feeding at the aviary.

This now brings the total number of free-flying choughs in Jersey to 38. Almost a quarter of which were wild born in Jersey. There is a video of the group in flight on Jersey Zoo’s Instagram page or just click here if you don’t have an account.

Lil’ Wheezy gets wormed

We needed to worm the sick chick that was now visiting the aviary twice a day. It couldn’t be done straight away. We needed the chick to become accustomed to flying in and out of the aviary in order to trap it inside. It took a good week for Lil’ Wheezy to grow in confidence and fly all the way in at each feed.

A wild fledgling caught up under licence to treat for nematodes. Note the bill colouration due to its young age. Photo by John Harding.

Patience paid off on the 19th when the team were able to trap it inside and catch under licence. Dave Buxton fitted leg rings and the Vet gave it a wormer before being released back to it’s parents and the rest of the flock.

Classic reaction to a vet holding a needle. Photo by John Harding.

MSc project wraps up

Guille finished collecting data for his research at the end of this month. He now has the delight of returning to Nottingham Trent University to make sense of it all. I will let Guille explain in his own words…

“Birds, and other animals have personalities. Consistent behaviours that are different between individuals, maintained through time and favouring -or not!- the survival of the individuals and their successful breeding.

Studying the boldness-shyness continuum in choughs. Photo by Liz Corry.

With the choughs I am looking at a classical behavioural trait: the boldness-shyness continuum and how it might affect survival.

Basically, if you are a bold bird you may be good at defending your food patch from others, get stronger and healthier and be able to feed your nestlings properly. However, if you are a very bold bird that would not leave the food patch even when there is a falcon approaching, you are in serious trouble.

I want to see if we can predict how far the released choughs will go to find food everyday just by looking at their personalities. Some studies have already shown that boldness has an effect on habitat use and distance travelled, which may be useful in a project like this one, where every bird is highly valuable and the distance they will travel will increase the chances of finding more food, or getting lost! If a correlation is found, it would help the project team to select which birds should be released depending on what behaviour is best to assure survival in the area.

Does Lee’s personality type predispose him to travel several kilometres away from the release site to feed? Photo by Mick Dryden.

For assessing their boldness, I presented them a squirrel-proof bird feeder that they had not seen before, as they have their daily supplementary feeding in open trays. I recorded the latency of each bird to pick food from it for the first time, during 15 minutes. After that, they were given their daily meal and I would not repeat the test until approximately ten days later, so they would not get used to it. Finally I gave every bird an average boldness score based on how long they took to pick food for the first time.

This year’s wild chicks were clearly not shying away from the feeder. Photo Guillermo Mayor.

Assessing the distance travelled was the fun part, as they had lost their radio tags. I had to become another chough and follow the group during their morning stroll. They leave the roost by 5am, returning for the 11am feed. I learnt lots about chough behaviour in the field. I saw their games, love arguments, gang fights, first trips of their chicks, but still they are very complicated birds.

By the end of July, after having cycled every single track of the north coast, I had a bunch of observations, from which I would pick the furthest point from the roost I saw each bird. Some of them were a bit surprising, such as Trevor and Noirmont. I found them perching on a German WW2 cannon, south of Les Landes. They looked like nobody could mess with them. I would definitely keep an eye on those two.

The two and a half months passed too quickly and I wish I could have stayed longer. The support I received from the project staff was amazing, and I would definitely recommend anyone that has cool ideas that would help the project and the broad bird recovery knowledge to think about doing some research here.

I am currently in front of the computer, missing the field and the choughs, and for now it seems that the boldness was consistent, which is good news! I really hope I can come back soon and see the noisy choughs again soaring over the windy cliffs, and all the lovely people who were like a family for a summer.”

Birds On The Edge wins a RHS award

BOTE award 001 (2)

Birds On The Edge received a Silver award in the conservation section of the annual ‘Parish in Bloom’ event, a hugely popular and well supported national floral competition held under the professional auspices of the Royal Horticultural Society.

Glyn Young met the judges and Mike Stentiford on Sunday 23rd July to show them around Sorel to see the grazing flock of sheep, conservation crop fields, and the choughs. Although only two choughs showed up!

More information about the Parish in Bloom event run by Natural Jersey can be found at http://www.parish.gov.je/Documents/NatJerBrochureA4_ParishSites.pdf.

 

Chough report: June 2017

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By Liz Corry

Chough numbers increase in the wild

Jersey’s free-living choughs have had another productive nesting season. There are seven pairs in the group and we discovered five nests. As reported last month, Dingle and Red’s clutch of four eggs failed to hatch.

That still left four active nests with chicks. The team was taken to the nest-sites on 9th July by Ronez operational assistant, Toby Cabaret. Dave Buxton, licensed ringer, joined the team in order to fit leg rings on the chicks.

We were initially greeted with bad news. We found two dead chicks on the floor under a nest, approximately two and three weeks old at time of death. Post mortem results were inconclusive due to decomposition of soft tissues. Fortunately there was still one chick alive in the nest.

Licenced bird ringer Dave Buxton with a chough chick. Photo by Liz Corry.

Fitting plastic leg rings and taking DNA samples for sexing. Photo by John Harding.

A second nest had also lost a chick leaving just one chick for the team to process.

The third nest was checked and also found to contain just one chick. In all of the above nests, the parentage was unknown; although we had our suspicions.

Each nest checked contained one chick. Photo by Liz Corry.

The fourth nest belonging to Green and Black was in one of the nest-boxes fitted this year. Despite the nest camera being blocked with wool and twigs we had strong suspicions there were chicks inside. Due to access issues it would be a case of waiting for fledglings to emerge to determine if this was the case.

On the 21st we received news from Toby that one of the ringed chicks had started to explore outside the nest. We estimated it would be a week before it made an appearance at Sorel.

Photo of the first chick out of the nest. Photo by Toby Cabaret.

We were right! On the 27th the dulcet tones of a begging chick could be heard over the cliff tops and upon its arrival at the aviary accompanied by its parents. Finally we knew who its parents were. Kevin and Bean were the only two choughs hurriedly feeding the chick. This was quite a moment for the team since young Bean is one of three hand-reared females at Sorel. There could only be one name for this chick; Beanie baby.

The first fledgling to arrive at the aviary begging for food from its parents. Photo by Tanith Hackney-Huck.

Our question over the fourth nest was answered two days before Beanie baby flew to Sorel. Paul Pestana’s voluntary observations paid off on the 25th when he spotted a commotion on the roof of one of the quarry buildings. Two chicks had jumped up through a hole in the roof and started begging frantically at Green and Black who had returned with food from Sorel. Within minutes of being fed they hopped back out of sight and the adults flew off to find more food.

This breeding season seems to be one of give and take. Therefore, our news of two unringed chicks was followed by news of a loss the next day. Concerned quarry staff phoned in the morning to report a chick on the ground in a building looking like it couldn’t fly. A somewhat common appearance in chough chicks that haven’t fully fledged. However, it soon became apparent it was more serious. Sadly the chick died before it reached the vets. A post-mortem showed a severe syngamus infection as likely cause. Black was showing symptoms of a syngamus infection. If she was ingesting infected insects it was highly likely she was also feeding them to the chicks. The survival of the second chick was now in doubt, but there was nothing we could do until it flew to Sorel.

Cliff hanger!

Chough travels

Whilst staff have been busy observing nests, the choughs have been off gallivanting along the north coast. Nottingham Trent student Guille has been attempting to follow them as part of his MSc project. He wakes at dawn and tracks groups or individuals armed with a pair of binoculars and a trusted bicycle. He also put a plea out to the Jersey public via social media to report any sightings. They didn’t disappoint.

After an initial slow start, Guille has been able to observe choughs foraging at Crabbé, Plémont, Grosnez, and Les Landes. All places we knew they visited already, but thought they had ditched during the breeding season to stay close to nest sites. At least that is the impression you get when you go to the aviary to feed twice a day.

One warm day, a pleasing find was seeing a group of choughs bathing and drinking in the stream at Mourier Valley. Rather more interesting was the discovery of the breeding pairs travelling several kilometres away from their nest sites. White and Mauve with at least 16 others were photographed at Grève de Lecq at the start of the month. We had started to think this pair had failed to breed this year, so it wasn’t too surprising for them to be away from their nest site.

Choughs photographed at Greve de Lecq on June 12th by Nick de Carteret

We suspected the Les Landes pair, Lee and Caûvette, were responsible for one of the chicks in the quarry. Guille’s observations and public reports meant that the pair were spending considerable time and distance (~5km) away from their nest to forage. Grosnez, Plémont Headland, and Les Landes being their favourite spots. Kevin and Bean were also spending time away from their nest having been seen 2-3km away  in the mornings and early afternoon.

Lee (on the left) and Caûvette photographed at Grosnez by Mick Dryden.

Catch up with Caûvette

We trapped Caûvette in the aviary at Sorel and caught her up to remove her back digit from her plastic leg ring. Unlike Bean she had not managed to free it unaided. There appeared to be no damage. The only thing was that claw had become overgrown and needed a trim. Once weighed she was released from the aviary to join the others. In the process of catching her up we also caught up Green and Q much to their displeasure. Not one to waste an opportunity we recorded body weights for those two prior to releasing. The two males and Caûvette were all good weights suggesting that they must be finding enough food whether wild or at the aviary.

An unappreciative Cauvette before her toe was removed from the plastic leg ring. Photo by Liz Corry.

Han Solo takes flight

Zoo chough chick Han Solo in the nest box…one imagines anyway.

Our zoo chick, Han Solo, took his first flight out of the nest box on 15th June and there wasn’t a Millennium Falcon in sight! Well maybe a kestrel hovering over the valley.*

He had been teetering at the edge for several days beforehand. Once out it took him a little while to get used to his new-found flying skills, preferring to hang out in one of two places. He doesn’t seem too perturbed by the public. We assume mum and dad have explained the situation to him.

Recently fledged chough chick and parents at Jersey Zoo. Photo by Liz Corry.

*apologies to anyone not a fan of Star Wars and to everyone for the bad pun.

RBC helps out Jersey Zoo’s own RBCs (red-billed choughs)

On 9th June a team from the Royal Bank of Canada volunteered their time at Jersey Zoo to help with the choughs.

Team RBC: The Royal Bank of Canada staff who volunteered their time for the Red-Billed Choughs. Photo by Gisele Anno.

They were set the task to weed the borders outside the display aviary and plant it up to look like chough habitat found on the north coast. Species such as foxglove, red campion, bladder campion, knapweed, lady’s bedstraw, birds foot trefoil and heather were added. Most of the plants were coming to the end of their flowering period, but they will grow back next year.

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RBC volunteers weeding the borders outside the chough aviary at Jersey Zoo. Photo by Gisele Anno.

Gorse bushes translocated from the old green lizard enclosure into the aviary when the choughs first moved in, have now spread to the outside. Volunteers made sure these young growths received a bit of TLC to encourage them to grow.

RBC volunteers working hard on the native species border. Photo by Gisele Anno

At the end of a hard day’s work they were treated to a talk from Glyn about Birds On The Edge, the choughs, and the reason why conserving coastal farmland is important.IMG_5806

On top of volunteering their time, the RBC have donated money to help rodent proof the release aviary and repair netting damage. For which we and the choughs are extremely grateful.

LIVE Teaching through nature

The choughs participated once again with Alderney Wildlife Trust‘s LIVE Teaching Through Nature schools programme. Their blogging skills almost as good as their flying skills if I may say so myself. The online paid programme offers schools the opportunity to bring nature into their classrooms by utilising live streams of Alderney’s seabirds, videos and blogs from Durrell and the choughs in Jersey, and the occasional live chat with field staff.

LIVE screen grab choughs

This project links directly to the key stage 1 & 2 curriculum, and is an effective way of teaching science and literacy skills, and encouraging pupil creativity and confidence. Feedback from our two week takeover in June was yet again positive hopefully inspiring some young conservationists along the way.

**CHANGE OF DATE** Puffins, petrels, and pests – saving seabirds across the Atlantic

Dark-rumped (Galapagos) petrel. Photo by Mick Dryden

We have had to change the date of the following presentation to Thursday 17th August. Still the same time, just a different date because Dr Swinnerton’s flight plans have had to change. Apologies for any inconvenience this may cause.

If you wish to attend please can you email elizabeth.corry@durrell.org to reserve a space as seating is limited.

Puffins, petrels and pests – saving seabirds across the Atlantic

An evening presentation by Dr Kirsty Swinnerton

Durrell Academy 17th August at 19.00

Kirsty will talk about seabird recovery work in the Caribbean (British Virgin Islands, Antigua and others), her own work in Puerto Rico and show similar work undertaken in the UK (Isles of Scilly, Hebrides etc) and how seabird recovery programmes might work in Jersey. She will show how the problems (pests) and recovery actions (pest management, social attraction, nest-boxes) are the same in the different regions for different seabirds and how we can exchange ideas and lessons learned across species, organisations and regions. She will also illustrate how some of the same species use both regions (e.g. Manx shearwater, Arctic tern) – and, therefore, require management actions in both regions to benefit the global population.

Please come along. Durrell’s Academy is across the Zoo’s car park Google maps

Puffin. Not in Jersey. Photo by Mick Dryden

 

 

 

Puffins, petrels and pests – saving seabirds across the Atlantic. An evening talk

Dark-rumped (Galapagos) petrel. Photo by Mick DrydenPuffins, petrels and pests – saving seabirds across the Atlantic

An evening presentation by Dr Kirsty Swinnerton

Durrell Academy 15th August at 19.00

Kirsty will talk about seabird recovery work in the Caribbean (British Virgin Islands, Antigua and others), her own work in Puerto Rico and show similar work undertaken in the UK (Isles of Scilly, Hebrides etc) and how seabird recovery programmes might work in Jersey. She will show how the problems (pests) and recovery actions (pest management, social attraction, nest-boxes) are the same in the different regions for different seabirds and how we can exchange ideas and lessons learned across species, organisations and regions. She will also illustrate how some of the same species use both regions (e.g. Manx shearwater, Arctic tern) – and, therefore, require management actions in both regions to benefit the global population.

Please come along. Durrell’s Academy is across the Zoo’s car park Google maps

Puffin. Not in Jersey. Photo by Mick Dryden

 

 

 

Birds in the Channel Islands – our lists updated

Black stork. Photo by Mick DrydenIn what has become a tradition, each year at around this time Birds On The Edge can unveil the updated list of Channel Islands birds. With kind support from our friends in the very active birding communities in Guernsey, Alderney, Sark and Jersey the list, updated to the end of 2016, can be downloaded here.

Blyth's reed warbler. Photo by Mick DrydenWhat has changed since the last list (to the end of 2015)? Well, that is very obvious to anyone looking closely at the species records and stems from the launch last year of the Alderney Bird Observatory. The team there in Alderney have started to immediately show big changes to our understanding of that island’s bird fauna and of bird migration through the Channel Islands in general. Several species joined Alderney’s list as it creeps up towards the numbers on the lists of the larger islands with first records of pomarine skua, penduline tit, Pallas’s warbler, western Bonelli’s warbler and Blyth’s reed warbler. And that was with less than 12 months activities – what will the next few years show? And where’s that CI first?

Pallas's warbler. Photo by Mick Dryden

The other islands’ birders have been no slouches either. Jersey added squacco heron to its total while there were other notable sightings with Guernsey’s second spotted sandpiper and third black stork, Jersey’s second greenish warbler and Alderney’s second velvet scoter, third subalpine warbler and fourth black stork, red kite and Alpine swift. Sark is lagging a little these days and it would be nice if visiting birders (it really is a good spot to visit), who must at least be able to assist with understanding species’ statuses on the Island, would send in all their sightings to the Sark recorder – the address is on the download.

Squacco heron. St Ouen's Pond 9-5-2016. Mick Dryden

Of the breeding species it is nice to see the numbers of little grebes, marsh harriers, common buzzards, little egrets and stock doves continuing to rise. There are disappointments as well though with declines in house martin, turtle dove and skylark.

And the Island totals of this totally uncompetitive listing of species? The overall number sticks at 370 and Jersey now has a list of 331, Guernsey 323, Alderney 291 and Sark 227. Each island continues to have what appear, to birders anyway, some glaring omissions. Why no red-throated pipits, lesser grey shrike, marsh sandpiper or Wilson’s petrel? Come and visit one or all of the islands, you’ll be made very welcome and you can maybe add something to this list in future.

A working list of the birds of the Channel Islands can be downloaded here.

Spotted sandpiper. Photo by Miranda Collett

Rural structures pose greater relative threat to birds than urban ones

Common yellowthroat (2). Photo by Mick DrydenFrom Rare Bird Alert

Further news on the numbers of birds that die each year colliding with buildings.

About one billion birds are killed every year when they unwittingly fly into human-made objects such as buildings with reflective windows. Such collisions are the largest unintended human cause of bird deaths worldwide—and they are a serious concern for conservationists.

A study published in June finds that, as one might suspect, smaller buildings cause fewer bird deaths than do bigger buildings. But the research team of about 60 also found that larger buildings in rural areas pose a greater threat to birds than if those same-sized buildings were located in an urban area.

The research team monitored 300 buildings of varying size and environmental surroundings for bird mortality at 40 college and university campuses in North America in the autumn of 2014. This included six buildings on the University of Washington’s Seattle campus. They designed a standardised monitoring protocol so that the field crews documented bird mortality uniformly. In all, they documented 324 bird carcasses of 41 species. At each site, somewhere between zero and 34 birds met their feathery demise.

Ovenbird. Photo by Mick Dryden

“Consistent with previous studies, we found that building size had a strong positive effect on bird-window collision mortality,” Hager and team wrote in a statement about the continent-wide research. “But the strength of the effect on mortality depended on regional urbanisation.”

Why is that? The researchers think it might be related to how birds select habitats during migration, and differences in bird behaviour between urban and rural populations. For example, they write, forest-adapted birds often select rural habitats with lots of open space and fairly few impervious surfaces over more urban areas.

Lighting patterns may also play a part, they reason. Lights from large, low-rise buildings in rural areas may act to attract migrating birds in what the team dubbed a “large-scale beacon effect,” where this effect may be “more diluted among large buildings in urban areas.”

Another theory is that urban birds may actually learn from “non-fatal” collisions and gain “new anti-collision behaviours” that help them avoid colliding with windows in urban areas. Previous research, they note, “suggests that the relatively large brain size in birds makes them primed for learning.”

The results suggest, the authors write, that measures taken to prevent bird collisions “should be prioritised at large buildings in regions of low urbanisation.”

The paper Continent-wide analysis of how urbanization affects bird-window collision mortality in North America, Biological Conservation can be seen here

Rufous hummingbird. Photo by Mick Dryden

 

Plea to dog owners after lambs are chased off cliff

p1730186From the Jersey Evening Post

Shepherd Aaron Le Couteur has urged dog owners to ensure their animals are kept on leads while walking in areas with lambs after two of his livestock were killed by being chased off a cliff.

The Jersey States police are now investigating following the incident, involving two Manx loaghtan lambs that grazed on land owned by the National Trust for Jersey near Devil’s Hole and are an integral and much-loved part of the Birds On The Edge project. Red-billed choughs need sheep!

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Aaron, who put his “heart and soul” into looking after the large flock, said that the incident was “incredibly frustrating”. “It happened at about 3 pm on Sunday [16 July]”. Two lambs were chased off the edge of a cliff by a dog and unfortunately died as a result. “Because there is an eye-witness the police are investigating, using the leads that they have available, and there is visual evidence” he said.

Aaron said that about 90 per cent of dog owners were responsible and had “exactly the right attitude”, but he added: “There is also the ten per cent who are a lot more difficult to get through to”. He added: “it is pretty obvious. There are signs on the gates as you walk in warning you that there are lambs on the site and to tell people to put their dogs on leads. We are trying to keep this open as a public space rather than restrict people from using it. What we have got to try to get across is that these are living, breathing animals and rearing them is no mean feat”.

Charles Alluto CEO of the National Trust for Jersey added “unfortunately some people do not appreciate that the land in question is agricultural land and in private ownership. Public access is totally at the discretion of the land owner and is a great pity that this is abused by a small number of people not fully controlling their dogs as requested at the entry points. All dogs, however well trained, are a potential threat to livestock as their inherent instincts can over-ride any controls. If this was more fully and widely appreciated then undoubtedly we could avoid such tragic incidents occurring in future”.

Under the Dogs (Jersey) Law 1961, it is an offence for dogs to chase or worry livestock or to not be under proper control. Anyone in breach of the law is liable to a fine of up to £1,000.

Read news about the sheep here

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