Want nesting petrels or puffins? Get rid of invasive mammals from their colonies!

It’s long been known that nesting seabirds and mammals don’t mix well. That’s why most species choose islands free of rodents and carnivores to nest. Smaller seabirds and those that nest down burrows are particularly vulnerable. And, if mammals get to those otherwise safe seabird colonies, you can expect the pretty rapid disappearance of the birds – they are either killed and eaten or they just don’t even try and nest. Unwanted species like this are called invasive and you can read all about this well studied issue through some titles below.

Birds On The Edge has covered several successful projects to remove unwanted mammals from seabird sites around the British Isles in Lundy Island, the Isles of Scilly, Calf of Man and the Shiant Isles. In Jersey we believe that mammals currently prevent breeding of storm petrel (they breed in good numbers in Alderney) and Manx shearwater and severely suppress our tiny Atlantic puffin population.

Storm petrel chick calling on the Shiant Isles from RSPB

A storm petrel chick has been recorded calling on the Shiant Isles for the very first time. This is an important step for the Shiant Isles Recovery Project as it’s the first known breeding of these seabirds on the islands. The EU LIFE+ funded project played an artificial call of an adult storm petrel outside the suspected burrow nest site to record the chick’s reply call and confirm its presence.

The project, a partnership between RSPB Scotland, Scottish Natural Heritage and the Nicolson family, the custodians of the islands, has been working over the last four years to make these islands, five miles off the coast of Harris, a safer place for Scotland’s globally threatened seabirds to breed. Island restoration projects such as this one are a key part of helping Scotland’s struggling seabird populations develop resilience to ensure their long term survival.

Storm petrels were not able to breed successfully at the Shiants because of their vulnerability to predation from the islands’ population of invasive non-native black rats. These were eradicated over the winter of 2015/16 and the islands were officially declared free of rats earlier this year.

Following the eradication, the project has been working to attract storm petrels to breed on the islands as it has ideal habitat for their nests in the many areas of boulders around the islands. These birds are little bigger than sparrows and only come to land in summer to breed. Scotland’s internationally important population currently nests at only a few offshore islands because of the presence of ground predators at other potential sites.

During the summer of 2017, calling storm petrels were recorded on the Shiants for the first time.

Dr Charlie Main, Senior Project Manager for the Shiant Isles Recovery Project said: “It’s fantastic that this storm petrel chick has been recorded on the Shiants. After the adult was recorded last year we thought it highly likely that they were breeding so to have this confirmed now is great for the project and for the species in Scotland. It’s also another vital step for making these islands a safer place for Scotland’s internationally important seabirds, many of which are struggling to cope with the impact of climate change and a lack of suitable secure breeding sites.

“We’ve strong hopes for the future that more storm petrels will breed here and a colony will be established. Three other calling adults were recorded this summer suggesting that there may have been more breeding attempts. This one chick is incredibly special to everyone who has been involved in the project since 2014; it means that all the work we’ve been doing to make and keep these islands free of invasive predators is paying off. It also shows just how quickly island restoration can make a difference to seabirds which is really positive for future projects like this one.”

And in Jersey?

In 2017, Kirsty Swinnerton, with Piers Sangan, undertook a preliminary review of the conditions available for nesting seabirds on Jersey’s north coast for Birds On The Edge. Kirsty’s report is now available here.

The recent establishment of the Jersey National Park and the acquisition of land at Plémont by the National Trust for Jersey has created some unique opportunities for seabird and habitat restoration. Historically, the north-west coast from La Tête de Plémont to Douët de la Mer supported 200-300 breeding pairs of Atlantic puffin but which have dwindled today to less than 10 pairs at most. The decline has probably been a result of an overall decline in the species’ southern range combined with the impacts of invasive species on Jersey including the brown rat, feral polecat/ferret, European hedgehog, European rabbit, and free ranging/feral cats. In addition, domestic dogs and agricultural stock (sheep and cows) could also prevent the re-establishment of puffins if not carefully managed at seabird nesting sites.

The report provides an overview of existing seabird recovery tools proven to re-establish breeding seabird colonies around the world. The primary focus is on the control of invasive vertebrates to increase the size and distribution of breeding colonies and reproductive success, and on hands-on species recovery techniques used to encourage seabirds to recolonise the area. However, during the study, it became apparent that much of the potential seabird recovery area does not support suitable habitat for puffins or other ground-nesting seabirds. The sites are choked with dense stands of bracken, and this may be the primary factor currently limiting colony growth of puffins and other burrow-nesting seabirds.

To understand more fully the impacts and interactions of invasive species, lack of suitable breeding habitat, and human disturbance on puffin colony re-establishment, the study recommended a pilot project combining species recovery techniques with research and monitoring. It further recommends initial small steps to maximise opportunities for feedback into recovery project development and the development of Species Action Plans for puffins and other seabirds by working groups in order to guide recovery efforts to include local seabird experts and stakeholders, and ensure best practices.

Download Kirsty’s full report Options for the recovery of nesting seabirds on Jersey, Channel Islands

Further reading on invasive mammals and seabirds:

Invasive mammal eradication on islands results in substantial conservation gains (2016)

Invasive predators and global biodiversity loss (2016)

Underlying impacts of invasive cats on islands: not only a question of predation (2014)

Severity of the Effects of Invasive Rats on Seabirds: A Global Review (2008)

Influences on recovery of seabirds on islands where invasive predators have been eradicated,with a focus on Procellariiformes (2016)

Chough report: October 2018

A pair of choughs have been foraging at this site in Corbière (can you spot them?) Photo by Liz Corry.

By Liz Corry

The choughs continued their travels around the Island this October with reports from Corbière, Noirmont and Wolf’s Lair.

Corbière lighthouse. Photo by Liz Corry.

Bo and Mary returned to Corbière this month. Photo by Liz Corry.

There have been several reports from La Pulente, the south end of St Ouen’s Bay. However, this may be a case of misidentification. This end of the bay often attracts large numbers of crows due to the rich pickings available at low tide. In amongst those are another corvid relative, the jackdaw. See our guide to corvid identification here

As the tide goes out at La Pulente the birds come in to feed. Photo by Liz Corry.

Jackdaws have a distinctly different call to crows. They are not as prolific in Jersey as they are in the UK. Understandably, if you are not used to hearing the calls of jackdaws and choughs together you could easily misidentify the two species. Of course there is one obvious way of telling the difference; one has a red bill, the other doesn’t. Not easy to spot when driving – most of the reports came from birders in cars.

Jackdaw calls are often misidentified as chough calls by Jersey residents. Photo by Liz Corry.

The difficult thing with all this is that birds can travel around the coast of Jersey much faster than humans. The birders out recording autumn migration numbers will attest to that. It is quite feasible that choughs were at Pulente, but nipped round the corner to Corbière before I had chance to follow-up the report.

View of La Pulente at the south end of St Ouen’s Bay (bottom left) and Corbière on the southwest corner of Jersey. Image from Google Earth.

End of British Summer Time…and the choughs’ travel plans?

When the clocks changed at the end of October so too did the attendance record at the aviary. We are now seeing more choughs at the supplemental feed. Forty-one being the highest on the eve of the clocks going back. That included Earl and Xaviour who have been living out at Plémont all year.

The increase in numbers is likely due to the cold snap and the reduction in wild food resources. Leatherjackets, a chough favourite, emerged as cranefly and spread their own wings removing themselves from the menu. The choughs reliance on the free food at the aviary will likely increase as we go into winter.

A leatherjacket casing in a coastal garden. Photo by Liz Corry.

The choughs appear to be spending more time foraging around Devil’s Hole and Mourier Valley. At least when the whistle blows for food at 3pm, the majority of the choughs fly in from that direction. They could be fooling us. Probably all are at La Pulente until 2.50pm!

Replacing lost rings

The return of certain choughs to the supplemental feed has made it easier to see who has lost which rings. A catch-up of birds on 28th October attempted to correct this. It took a while to trap the birds in the aviary; the hatches had seized up again despite a check the day before.

It was also a lot harder now there are so many. We managed to lock in about two-thirds of the group and went about the process of hand-netting individuals to check rings.

Bird Keeper Bea Detnon and a very compliant Mauve waiting in line for new leg rings. Photo by Hannah Clarke.

There are several birds we knew needed rings such as Green who had lost all but his original metal ring. Then there were others like Mauve who, on closer inspection, had broken rings creating sharp, hazardous, edges.

All the birds we caught in the nets were weighed and checked over prior to release. There were twelve who got locked in the aviary that we didn’t need.

In amongst this last group was Xaviour who has been missing her orange rings since the start of summer. Unfortunately, she evaded capture. Clearly living out at Plémont has improved her flying skills in close quarters. Since we had already spent an hour catching and processing everyone we called it a day to avoid excessive stress on the group.

Five others still require ring replacements. Weather permitting; we can do that in November.

Feeding stations

A new design of feeder to ensure the choughs get food and nothing else does. Photo by Liz Corry.

Work on the new and improved magpie-proof feeders continues. A quick trip home to see family turned into a research and development trip for the choughs. B&M Bargains, Hobbycraft, Aldi, Lidl….ah the joys of mainland shopping…all threw up some new ideas.

The latest and most successful is a rather unusual choice – flower urns. With slight modification to the container depth, they make the perfect magpie-proof feeder. At the cost of £5.99 for two, salvaged wood and paint (hence the colour choice), they are relatively cheap and easy to make.

To end on a non-bird related note…

At the start of October, the waters around Sorel were graced with the presence of bottle-nosed dolphins. Clearly visible from the cliffpath, the small pod followed alongside a Jersey Seafaris rib as passengers toured the north coast. I tried to capture an image of both choughs and dolphins, but, let’s face it, with my long lens focused on the dolphins; the choughs never stood a chance.

Jersey Seafaris tour joined by bottle-nosed dolphins at Sorel Point. Photo by Liz Corry.

 

Chough report: August 2018

One of this year’s chicks in need of a name. Photo by Liz Corry.

By Liz Corry

Zoo choughs

Keepers were in shock this month after the loss of two choughs in the Zoo. On 8th August a male was discovered by a keeper on the floor of the aviary. From his physical appearance, staff assumed the chough had been in a fight with Tristan, the only other male in the group, and lost.

The male chough had x-rays taken to assess injuries. Photo by Liz Corry.

When a second chough, Issy our breeding female, became ill we suspected there was more to it. The male’s condition gradually worsened despite efforts and eventually the bird had to be euthanased. Sadly, the female died a few days later.

Andrew Routh, Head Vet, explains “We took blood samples that were analysed in-house, at our usual diagnostic laboratory in the UK and, additionally, forwarded on by them to a specialist also in the UK. We will be re-sampling the remaining three birds in the collection. Full post mortem examinations were carried out on both birds and a comprehensive set of tissues from each sent for analysis by board-certified pathologists in the UK. No conclusions yet on the cause though further tests are pending.”

The remaining three birds have been taken off-show to individual enclosures for close monitoring. So far, they have shown no signs of ill health, are eating well and chatting loudly. Gianna, the Italian diva that she is, is a tad miffed we have taken her away from her public. Hopefully we can return them soon at which point the chough keeper talks will resume.

Wild chicks update

The last unringed wild chick was caught up on 1st August to be fitted with leg rings. Whilst in the hand, the chick made noises we’ve never heard before. And no, it wasn’t because we were squeezing too hard! There is debate as to whether the sounds were more gull-like or goose-like. Either way the ‘meeping’ chick became the first of the 2018 group to be named – Beaker.

The last of 2018’s chicks to be ringed (left!) and his namesake Beaker (right) – both emit unusual sounds. Photo by Elin Cunningham.

Two weeks later the DNA results returned form the UK lab. Whilst teenagers across the land were jumping for joy over their exam results, we beamed with delight upon hearing we have five males and four females.

This is great news for the Jersey population because:

(1) The sex ratio for wild-hatched choughs in Jersey is now 1:1. For the entire flock, it is more like three females for every two males. Not quite as catchy. Still a good result;

and

(2) We can name the new chicks! Aside from Beaker we had names lined up for Dusty’s chicks. In honour of Ronez’s assistance with the project, the three boys are now known as Clem (who found the chicks), Toby, and Osbourne (Ossy for short).

Tempting as it might be to call Beaker’s sister Dr Honeydew, her name is still open to debateWe are still searching for appropriate Jersey-related names for four females and a male. Please use the comments box to put forward any suggestions.

Parents Chicks 
Dusty & Chickay Clem (male) Toby (male) Ossy (male)
Kevin & Bean Green (female) Orange (female)
Lee & Caûvette Yellow (female) Black (male)
Q & Flieur Mauve (female) Beaker (male)

The 2018 chicks now have the adult colouring in their legs and bills (adult behind the chick). Photo by Liz Corry.

Spreading their wings

The flock have shown a distinct change in behaviour this month. After the chaos over June and July when chicks had to be fed and wild food supplies had dried up, the adults are relaxing back into their normal routines. One fortunate member of the public snapped a photo of 30 choughs flying over Plémont. On the back of this, social media reported seeing ‘large’ groups back at Les Landes.

Choughs flying over Plémont headland. Photo by Anne Gray.

The change is partly due to the chicks becoming independent and feeding themselves.

A major factor will be the rise in wild food supplies thanks to the shift in weather. Leatherjackets in the soil and dung-loving insects will provide the calories needed to fly back and forth around the north-west coast.

We are seeing an average of 24 choughs at the supplemental feeds. They appear to be the same individuals; all families bar Lee and Caûvette‘s making up half the group. Their willingness to enter the aviary has taken a knock since the recent spate of catch-ups. We have to reassure them that entering the aviary does not always result in humans waving nets around.

Having a wild food source around provides them with options. Great for them. For staff not so much, as it means the birds are less likely to hang around the aviary. Health screening, weight checks etc. are not as easy.

Chough chick photographed back in July at Sorel. Photo by Peter G. Hiatt.

Now you sheep me, now you don’t

Lack of choughs at the aviary is being compensated by appearances of sheep within the perimeter fence. The first sighting was on one of the hottest, driest days of the summer. A young sheep was happily curled up in the shade of the aviary sheds munching on lush green grass whilst the others were lined up along the hedgerows competing for shade. Much to the sheep’s dismay it was returned to the flock.

The next day it was back! And once again returned to the flock. A day or so later a different sheep was present. Neither student or I could figure out how on earth they were getting through the locked gate and wire fencing.

Days passed, sheep were absent. Or so we thought. Camera-trap footage to investigate chough roost activity threw up a different mystery. A ewe present in the morning, had gone by the afternoon. Clearly they were playing games with us.

Camera trap image inside the aviary showing a sheep within the aviary perimeter.

They upped the stakes in the last days of August. Having hidden in the bracken, ‘Houdini’ found her way inside the aviary. True magicians never reveal their secrets – except when their hooves and horns knocking equipment over in the keeper-porch give them away. I had left both doors open, not expecting her to follow me in, but it meant she could safely hang out in the aviary until the shepherd reached Sorel. And saved me a job with the lawnmower.

Yet another prime example of how the conservation of one species can benefit others.

Chough report: April 2018

Dave Warncken Chough desalination plant 21April2018_01

Choughs are now frequently foraging on the southwest tip of Jersey. Photo by Dave Warncken .

by Liz Corry

There is a hashtag floating around the social media stratosphere at the moment, #conservationoptimism, which pretty much sums up this month’s chough report.

When the reintroduced choughs started breeding in the wild in 2015 there were just two males and four females. Three years later we have twelve pairs all eager to contribute to the growing population. Furthermore, two of those pairs have decided to branch out and nest in other parts of the Island.

Nesting ambitions of Jersey’s choughs

A male displaying to his female to encourage ‘sexy time’. The female reciprocating with a suitably unimpressed look. Photo by Elin Cunningham.

We have been able to identify a record number of ten nest sites this year.

Specific details of nest localities will remain guarded in order to protect the pairs. I can, however, let you in on some of the ‘highlights’ we have witnessed in April.

All of last year’s sites in Ronez Quarry are being used again with slight tweaks here and there.

There is concern for Red and Dingle as they are using the nest located on hot piping again. Ronez Quarry are helping us look into ways of raising the nest off the pipes without destroying the integrity of the nest. We wouldn’t want their eggs to overheat like last year.

Red and Dingle’s nest guarantees chicks won’t fall out – providing the eggs survive the heat from pipe work underneath. Photo by Liz Corry.

Dusty has strengthened his bond with Chickay after Egg died and continues to use the upper quarry away from the hubbub of the other nest sites. They have built a very nice nest which should be easy for us to monitor.

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Ronez Quarry with Sark in the background. Photo by Liz Corry.

The first nest located away from Sorel was discovered by one of our zoo keepers on their day off. Anyone visiting Plémont in April will more than likely have heard if not seen a chough or two. In the months leading up to the breeding season we had assumed it was the Les Landes pair. And more often than not it had been. However, on reading the leg rings of the twig-carrying choughs it was clear we had a different pair.

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Plémont Headland. Sorel Point lighthouse just about visible in the background. Photo by Liz Corry.

Finding the nest was a little trickier and not for the faint hearted. It is within the Plémont seabird protection zone which imposes public access restrictions from March to July. Plémont’s cliffs, notorious amongst Jersey’s rock climbers, are described as being ‘Weetabix’ like in structure and to be avoided at all costs. All in all there should be little human disturbance at this site adding to our growing optimism.

Not only is this the first nest discovered away from the release site, it is the first to belong to one of our foster-reared females – Xaviour! She has partnered with a male of her own age, Earl, and as such we are not expecting too much from them. At two-years old they are first timers with no knowledge of exactly what is involved in parenthood.

Regardless, this is a small victory for the project; foster-reared birds can pair up, they can build nests, and not just any nest, a truly wild nest. Fingers (and primaries) crossed for the next few weeks.

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A male chough displaying his ‘excitement’. Photo by Liz Corry.

The record-breaking didn’t stop there. The choughs added a third parish to their tick list of breeding sites. Mary and a wild-hatched male from 2016 were found to have moved roost site 7km to the parish of St Peter. They have been a fairly permanent feature of Simon Sand & Gravel Ltd since last year. Jason Simon, Managing Director, reports seeing three choughs around, but of late one had been ‘pushed out’ by the pair.

Simon Sand & Gravel Ltd located in St Ouen’s Bay is home to sand martins and now choughs too. Photo by Liz Corry.

Two choughs have taken up residence at Simon Sand & Gravel Ltd in St Ouen’s Bay. Photo by Elin Cunningham.

Twigs are visible in the location where the pair roost. It could be a red herring as the site is also used by pigeons. From observations, Mary appear’s quite faithful to that particular spot.

The pair continue making the return trip to Sorel for the supplemental feed. You would assume from this that they are not finding what they need in the wild travelling at least 14km a day for the guarantee of food.

Not so. Thanks to several public sightings, and wonderful photographs, we know that this pair are frequenting Corbière, the southwest tip of the Island.

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Wild-hatched chough hanging out at Corbière 21st April 2018. Photo by Dave Warncken.

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Mary and a wild-hatched chough have become permanent residents of the southwest corner of Jersey. Photo by Dave Warncken.

Funding for nest monitoring awarded by the Ecology Trust Fund.

JerseyEcologicalFund

We are very proud to receive funding this month from the Ecology Trust Fund.

This is a Jersey-based  fund established in March 1991 by the States of Jersey with a sum of money received in an insurance settlement from the Amoco Cadiz oil tanker disaster of 1978. Annual interest accrued is used to finance multiple projects each year within the environmental sector.

The money will be used to purchase equipment to help the team monitor chough nests around Jersey. Increasingly important as our birds ‘leave the nest’ and set up home around the Island.

Island Insurance Corporation awards

CaptureStaying on a funding and monitoring theme, we are very honoured to hear that Ronez Quarry have nominated the chough project for the Islands Insurance Corporation Conservation Awards. The choughs have frequented the quarry since the trial release in 2013 which is now permanent residence for several pairs.

There are prizes to the value of £1000 and £500 available. If awarded, we will be able to cover the costs of monitoring, ringing, and sexing the wild-hatched chicks. DNA sexing tests, for example, cost £14 per bird.

With 10 potential clutches this year the costs could soon spiral.

Judges will visit the short-listed projects in May after which voting will open for the People’s Choice Award. We will circulate details as soon as voting opens.

Replacement rings

This chough had lost both plastic leg rings. The unique metal ring is impossible to read at a distance. Photo by Liz Corry.

As previously reported, several of the choughs have been losing their plastic rings. Or in the case of Zennor switching them around. As if the team needed more of a challenge to monitor breeding pairs!

On 26th April a group of choughs were caught up at the supplemental feed. Nine of the 25 birds arriving for food were caught up, weighed, and given new replacement rings. White was the only exception in that we had run out of white rings and given grey instead. Off-White if you like.

They all looked to be in good health. None of the females sported brood patches to suggest they had started incubating. I suspect that will have happened towards the end of the month or early May.

We still have two birds requiring replacement rings. They happen to be two of the four now living away from Sorel. Unlikely we wil get them in the aviary anytime soon.

Zoo news

Change is afoot with the Zoo choughs. We are exchanging chough pairs with Paradise Park, Cornwall, as part of our wider departmental collection plan. Paradise Park have kindly agreed to take Lucifer back after loaning him to us in 2012. Hopefully they can address his egg-smashing behaviour.

Jersey Zoo will continue to house two breeding pairs; Tristan and Issy and a new established pair. The move has been delayed until May which will disrupt the breeding season. With a quarantine period of thirty days it is unlikely the new pair will breed at Jersey this year.

Tristan and Issy remain in the Zoo’s on-show aviary and have already started nest building. Keepers found a discarded egg and the nest-liner on the floor of the aviary towards the end of April. Something obviously unsettled them, but they have started gathering wool again to repair their nest.

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Tristan and Issy collect wool to line their nest in the Zoo. Photo by Liz Corry.

Foster rearing might not be on the cards this year

Gianna is making good progress since her cataract operations. It was clear that she had regained sight post-op, but she was not her normal self. At lot was due to a knock in confidence. Living in the dark for several months and then placed in a different enclosure must be disorientating. She also behaved in a way that suggested her depth perception was a little off. Over time she has improved although it could take a couple more months to be fully adjusted.

 

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Gianna enjoying her morning preen. Photo by Liz Corry.

She is now in the off-show foster aviary allowing her to go through the motions of nest-building and such. A great deal of enthusiasm has been expressed although she still doesn’t have a complete nest. By now she would have finished and be eager to start laying.

Tristan and Issy did not need any assistance last year with raising their chick. As the only active breeding pair this year it is unlikely we will need Gianna’s help. Only time will tell.

That, and May’s monthly report!