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Save Our Shearwaters

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Spanish Senate Calls for Greater Efforts to Save Balearic Shearwater

Spain's Senate has called on the Spanish Government to strengthen efforts to prevent the Balearic Shearwater, Europe's only critical endangered seabird, from becoming extinct. On 27th April 2017 the Senate's Committee for Environment and Climate Change has unanimously approved the motion put forward by Francesc Antich, socialist Senator for the Balearic Islands.
Antich warned during the Senate debate that unless urgent action is taken, the seabird "could be extinct within 60 years, and if it disappears from our country it will be wiped from the face of the Earth forever". 

The motion calls on the Spanish Government to collaborate with the fisheries sector to modify fishing methods which contribute to the shearwater's decline through accidental by-catch, and to strengthen programmes to eradicate rats and other predators. 
Drawing on research conducted for IMEDEA, SEO/Birdlife and other bodies, the motion calls for greater coordination between political actors at national, local and European level to ensure the species' survival.

End of Spring 2017 fieldwork update

On 19th April, our Spring 2017 campaign came to an end. Despite challenges in acquiring permits to continue our long-term project in Sa Cella, we finally managed to deploy a total of 15 GPS and 8 accelerometers - all of which were retrieved between 10 and 14 days after deployment. All the birds continued incubating normally. This was especially successful because this year we deployed GPS at higher resolution and this seems to have worked well with all but one GPS device recording a full trip before their batteries ran out. This included a bird, which for the first time from Sa Cella, was tracked to the Algerian coast (see figure below) which was an intriguing surprise. We hope that, in combination with high-resolution saltwater immersion loggers, these higher-res data will help us identify foraging on a minute-by-minute basis. This will help us quantify an individual shearwater’s risk of death due to by-catch and ultimately understand demographic risk-predictors. Such information will inform the discussion on how to mitigate properly against the effects of by-catch on this species as we push for a Europe-wide, cooperative and sustainable plan to tackle its decline.

The first Balearic shearwater from our long-term tracking in Sa Cella to visit North Africa to forage. In the figure it can be seen to spend 4 days feeding off the coast of Algeria. Interestingly, this bird also seems to visit Ibiza en route back to Sa Cella.

We retrieved the majority of geolocators that had been deployed in the 2016 season (though sadly, with 0.81 annual survival, retrieving all of the devices deployed each year is very unlikely). Nonetheless, these data contribute to a growing, long-term dataset in which we can identify key features of the Balearic shearwater’s annual cycle (Meier et al. 2015; 2016). The long-term project has also received some much needed media attention locally, and Tim was interviewed for El Mundo newspaper about the study and the need to act on the decline in the species. This year, we have carried out our work in collaboration with with the Grup Balearic d'Ornitologia (GOB). You can read about their organisation in Catalan here or in English here. We would like to take this opportunity to thank GOB for the support our project received this year allowing the project to continue. We would also like to thank the Balearic Government and Dragonera and Cabrera park staff for such generous support throughout the campaign.

Cabrera – a declining population?

This year, we began a Natural England and RSPB funded long-term geolocator tracking campaign on Cabrera. Finally we got the opportunity as the permits and weather conditions came together in our last week, allowing a trip to this impressive archipelago 7.3 nautical miles south of Mallorca. We aimed to track at three nesting sites, all on one of the islands that make up Cabrera, known by Miguel McMinn from projects there in the early and mid 2000s. After a smooth crossing in our spruced up boat we were landing on Illa des Conills (Island of the Rabbits); a small and beautiful uninhabited islet to the east of the main island of Cabrera. Miguel had last visited this island in 2007 and was optimistic about our chances of gaining access to Balearic shearwaters nesting there.

Tim had an interview with the newspaper el Mundo about studying the at-sea lives of Balearic shearwaters. How do we know where they go? What do they do when they get there? Why are they at such high risk from by-catch? Translation of article to be released here soon.

Despite some tricky boat handling we managed to make landfall on the south coast of Ille des Conillis as planned. Unfortunately, soon after we began searching for nests it became evident that there has been what appears to be a drastic decline in the Balearic shearwaters breeding there. We found three active nests in over an hour of searching but these were inaccessible – there were no longer enough suitable nests for tracking at this sub-colony. This was a big blow. In 2007, this area had many accessible nesting sites and for our Cabrera campaign, this was the first sign of what may turn out to be a spectacular population crash in the Cabreran archipelago. All that was left at most nesting sites were the skeletal remains of what must once have been a significant colony and the odd ring as ghosts of monitoring projects past. Realising that we wouldn’t be able to easily track at this site, we moved to the second of our planned sites.

Our boat with its new engine just returned from Cabrera. Lots to do getting the boat out of the water after a long day.

The second site we visited on the island was a fantastic cave system up some steep rocks from the sea. We climbed up and entered the cave and finally, some shearwaters! As we crawled in, we found birds nesting openly on the floor in a sandy chamber deep in the cave system, in some ways similar to Sa Cella. However, our initial excitement of finding shearwaters was dampened by Miguel’s accounts of the numbers that had previously bred there. But even with reduced numbers of breeding birds, we managed to GLS tag five nesting Balearics, and find some more nests and non-breeding birds that we were unable to tag. Despite small numbers, however, the cave is well suited to monitoring and ideally in the future will form the basis of a Cabrera study colony to confirm that the high turnover rate in Sa Cella (Genovart et al. 2016) is representative in other parts of the species' range.

A Balearic shearwater on Dragonera, where activity seems to be increasing following rat eradication. This one has had a geolocator fitted to its left leg for the third year running.

A third and final cave on Ille des Conills was a site which was thought to be one of the only known sites in the world where Balearic shearwaters, Scopoli’s shearwaters and European/Mediterranean storm-petrels breed together. Entering the cave, it’s easy to see why - perfect, boulder-strewn storm-petrel habitat and dark corners which, on our visit, were occupied by a single pair of Scopoli’s spending a day in the cave before breeding. However, as we made our way deeper into the cave, where the habitat becomes ideal for our birds, there were no Balearics. They seem not to breed here anymore. And so, disappointed, we left Cabrera with five geolocators deployed, all at our second site. A day on which we had anticipated to deploy geolocators on 20+ nesting Balearics turned out to be a day of uneasy discovery.

Finding only five nests for deployment demonstrates how difficult it is going to be to track birds from the Cabrera archipelago. Unfortunately, there has been no monitoring on Cabrera of Balearic shearwaters since 2007 and so we know very little about the cause or nature of the decline in the last decade. This highlights the importance of monitoring and tracking work on Balearic shearwaters on these islands to assess population decline and at-sea risk during the non-breeding period. To me, it seems likely that the decline is driven by the same factors as for the species at large - primarily poor adult survival as a direct result of high rates of by-catch in long lines (Cortés et al. 2017). While we saw no direct evidence of rat predation, the status of brown rat on the island is unknown and consequently also remains a serious conservation concern on the island that is close to rat-inhabited Cabrera (0.7 nautical miles).

Sa Cella, the largest known colony of Balearic shearwaters in the world is deep in the impressive cliffs on northwest Mallorca.

Despite the inherent difficulty of tracking on sparse colonies, this reconnaissance mission has demonstrated exactly how important it is to persist and succeed in tracking on Cabrera. Our observations serve to highlight that large numbers of Balearic shearwaters sighted offshore might obscure serious decline in the species and reduce the impetus to act locally or across Europe. It also supports the idea that the steady numbers of birds that we observe breeding in Sa Cella, the site of our long-term study and the largest known Balearic shearwater colony in the world, are not indicative of a stable population. It is likely that high levels of recruitment to this colony mask a decline which is better represented by the low adults survival and high turnover (Genovart et al. 2016). Our original motivations to track on Cabrera are now more evident than ever. Are these birds spending the same amount of time in the Mediterranean and the Atlantic? Are they subject to the same risk to by-catch in demersal long lines as the other Balearic (and Scopoli’s) shearwaters in the western Mediterranean? And, now, why are these caves ceasing to be occupied whilst Sa Cella recruits new birds annually? We need to call on interested parties to work together to monitor, study and campaign for the protection of this species at sea as well as at their colonies. This may involve difficult conversations, but the time to act is now.

With a world population estimated at 25,000 individuals and little population monitoring, the Save Our Shearwaters project now has a void to fill - to understand the decline of shearwaters on a second colony. Ille de Conills.

Spring 2017 update

Ollie Padget and Sarah Bond joined Miguel McMinn in Mallorca on March 21st to prepare for our 2017 campaign, sorting out final permissions and logistics. We have finally replaced the old outboard with a new one which works brilliantly, but this has drained our financial resources completely. At least we can sail safe! Tim Guilford, Lou Maurice and Natasha Gillies joined at the weekend and after a final wait for permits we were blessed with good weather and easy access to the Sa Cella. This year we are concentrating on trying to recover geolocators from birds tagged as chicks, who should now be returning to breed four years later; studying the migration patterns of birds breeding at more diffuse colonies (such as Cabrera) to see if these are coming further north to UK waters (with support from Natural England); and using GPS and accelerometers to determine more precisely the diurnal patterns of foraging activity.

So why are we doing the latter? Our data so far suggest that Balearic shearwaters do not feed at night, so a potential mitigation measure to reduce by-catch would be to set demersal longlines at night so that the birds are not tempted to dive for the sinking baits and consequently drowning on the hooks. Evidence from our colleagues at Barcelona University strongly indicates that night-setting could be effective against what evidence suggests is the major cause of decline towards imminent extinction, and into the bargain would not reduce catch for fishers. But there is reluctance to adopt such a measure, and still no sensible mitigation against by-catch has been implemented. To cement our understanding of by-catch risks and the likelihood of mitigation effectiveness we are now trying to assess whether in fact Balearic shearwaters might sometimes forage at night under a bright moon, or in the proximity of city light pollution. We are using high resolution tracking devices this year, and at different moon phases, to try and find out.

We also hope that our accelerometers (a collaboration with Emily Shepard at the University of Swansea, UK) might allow us to determine how much time birds spend scavenging behind different kinds of fishing boat, and so allow an assessment of relative risks from the birds’ perspective. As always field ecology is difficult and uncertain, so we will see how the results look when they come in.

Meanwhile, at 5th April, most of our devices have been deployed and we are now waiting for birds to go to see and return. Flea bites have been a particular hazard this year, but one piece of good news is that we have had the liveliest nights of shearwater display calls around the little harbour at Dragonera that any of us can remember. So far our artificial nest boxes have not been used, but new birds may be using natural nest sites. The implication seems to be that post rat eradication (still no sign of rats five years later!) Dragonera is starting to become more active as a breeding colony. This has to be good news!

Balearic shearwater to become an ACAP Priority population.

The Agreement on the Conservation of Albatrosses and Petrels (ACAP) promotes globally the conservation of one of the fastest declining groups of birds on earth, by bringing together collaborative information and mitigation efforts and action especially where threats are known (for example from introduced predators or fisheries’ by-catch). 13 countries are signatories of the agreement, including Spain where the Balearic shearwater breeds, and UK and France into whose waters the species migrates after breeding. Most of the 31 species listed by ACAP are at least vulnerable, and many are recognised as endangered or critically endangered according by the IUCN. Within this group of seabirds, ACAP also now recognises a small number of populations that according to scientific evidence on their rates of decline and interaction with fisheries, must be regarded as the highest priority for monitoring research and conservation action. At its most recent meetings in Chile, ACAP has now recognised the Balearic shearwater as a priority population, making it one of only 8 such populations and the only one in Europe or indeed the entire northern hemisphere. The hope must be that with this ever brightening spotlight on the significance of this species within Europe and globally, the relevant national authorities will now take action to reverse the species’ precipitate decline by introducing by-catch mitigation measures (such as night setting of demersal long-lines already shown to be effective).


Mallorca 2016 NEWS

2nd April
A spell of good weather at the end of last week and the beginning of this one allowed us access to the colony and so we finished deploying a total of 27 GPS and have begun retrievals, with 12 back so far. The wind has turned northerly again now and so access to the colony has again become impossible. We have almost finished the geolocator redeployments on Dragonera. Here is an example of the tracks we have been getting back.

23rd March
Access to the main colony is still not possible because of north winds and a big swell. We attended a very constructive meeting at the Institute of Mediterranean Advanced Studies with Dani Oro, members of the Balearic Ornithological Group (GOB), and Caterina Amengual, from the conservation department of the new Balearic government administration.

22nd March
Today the north wind howls and access to our main colony by RIB is not possible. But 4 good days have allowed us to deploy 12 GPS and 2 accelerometers and recover/redeploy 12 Geolocators. We have retrieved our first camera trap pictures of Balearic shearwaters mating in the cave! We spent the day retrieving and redeploying geolocators in the small caves on Dragonera.

2016 Project update

Recent demographic analysis using multievent capture-recapture modelling shows that the Balearic Shearwater (Puffinus mauritanicus), Europe’s most threatened seabird species, is heading rapidly towards extinction. Unsustainably low adult annual survival (0.809 +/- 0.013) is the principle concern, with bycatch in fishing gear identified as the major cause of mortality (Genovart et al., 2016). Reproductive rates are also relatively low, with the upcoming ban on fisheries discards likely to depress these further, at least in the short term.

Our own work on Balearic shearwaters focuses on unravelling the mysteries of its extraordinary life-style (it’s the only seabird to nest deep underground in caves, for example), and particularly its behaviour at sea. On Mallorca using miniature GPS loggers we have confirmed the importance of long distance foraging commutes to mainland Spanish coastal waters in the Mediterranean (Meier et al., 2015). Long- term geolocator (GLS) deployments show that breeding birds migrate out of the Mediterranean after breeding to feed in Atlantic coastal hotspots, mainly off Portugal and France (Guilford et al., 2012).
Hooks (from demersal longlines) are probably the biggest killers in the Mediterranean foraging areas, but other fishing gear (e.g trawlers and purse-seiners) can cause occasional large numbers of deaths in the Atlantic (Oliveira et al., 2015).

Balearic shearwaters are increasingly reported in UK waters in the southwest in late summer, but we still do not know whether these are breeding adults or immatures (something we are currently trying to resolve by tracking fledglings with GLS). The risk of bycatch in UK waters remains unknown.

Repeat tracking shows that birds are highly faithful to their individual destinations, with males and females preferring differing locations. Females, who spend longer in the Atlantic than males, migrate further north, and isotopic analysis of their feathers moulted at different times suggests that they may be more dependent on fisheries discards there, although this is of low certainty (Meier 2015).

Back in the Mediterranean, we now know that birds appear only to dive for fish during the day (Meier et al., 2015), so night-setting of demersal longlines should provide a technically simple method for reducing bycatch. Indeed research at Barcelona University by Jacob Gonzalez-Solis and Vero Cortez has shown experimentally that night-setting is the most effective mitigation measure available and causes little or no reduction in fish catches.

In 2016 we are co-ordinating our GPS tracking campaign on Mallorca with Spanish colleagues Pep Arcos and Maite Louzao in Ibiza to try to determine the degree of segregation in Mediterranean foraging areas between major colonies – an important piece in the demographic puzzle. We are also developing methods for quantifying individual dependence on different foraging modes (natural and different fisheries scavenging behaviours) using on-board video-loggers and accelerometry (with Emily Shepard).

The natural park of Dragonera provides us with great facilities for conducting this work, which is made possible by the generosity of volunteers, and donations from Natural England, RSPB and private individuals – in particular Mark Constantine and Steve Votier. If you feel motivated to help, please use our campaign page below.


Genovart, Meritxell, Jose Manuel Arcos, David Álvarez, Miguel McMinn, Rhiannon Meier, Russell Wynn, Tim Guilford, and Daniel Oro. "Demography of the critically endangered Balearic shearwater: the impact of fisheries and time to extinction." Journal of Applied Ecology (2016): n/a - n/a.

Meier, Rhiannon E., Russell B. Wynn, Stephen C. Votier, Miguel McMinn Grivé, Ana Rodríguez, Louise Maurice, Emiel E. van Loon, Alice R. Jones, Lavinia Suberg, José Manuel Arcos et al. "Consistent foraging areas and commuting corridors of the critically endangered Balearic shearwater Puffinus mauretanicus in the northwestern Mediterranean." Biological Conservation 190 (2015): 87-97.

Guilford, T., R. Wynn, M. McMinn, A. Rodríguez, A. Fayet, L. Maurice, A. Jones, and R. Meier. "Geolocators Reveal Migration and Pre-Breeding Behaviour of the Critically Endangered Balearic Shearwater Puffinus mauretanicus." PLoS ONE 7, no. 3 (2012): e33753.

Oliveira, Nuno, Ana Henriques, Joana Miodonski, Joana Pereira, Débora Marujo, Ana Almeida, Nuno Barros, Joana Andrade, Ana Marçalo, Jorge Santos et al. "Seabird bycatch in Portuguese mainland coastal fisheries: An assessment through on-board observations and fishermen interviews." Global Ecology and Conservation 3 (2015): 51-61.

Balearic shearwater campaign

Europe’s rarest seabird is the Balearic shearwater (Puffinus mauretanicus), which breeds in the Mediterranean and migrates north into the Atlantic in the summer. It is seen increasingly off Britain with perhaps ¼ of the world population visibly using our seas at times in late summer. But it is critically endangered, and faces as a species a deeply uncertain future. Despite this, still remarkably little is known about its behaviour and ecological needs: knowledge which must underpin conservation efforts to avert its extinction.

You can help

Balearic shearwater at sea

At OxNav we have been collaborating with scientisis at the National Oceanographic Centre in Southampton, with Spanish biologists in Palma and elsewhere, and with the RSPB, to try to fill important knowledge gaps and raise awareness of the species’ plight. We have been engaged in answering fundamental questions about where and how breeding birds feed (and how this relates to human fisheries), where they overwinter, and their patterns of colony use in the pre-breeding months. We are now trying to determine the provenance of birds using UK waters, which we think may be non- or pre-breeders becoming increasingly dependent on our waters as the changing climate drives important marine resources north. And we are setting up longer term monitoring efforts to help assess key changes in breeding success, overwinter survival, and patterns of breeding and migratory phenology.

Our research efforts have always depended on voluntary contributions of time, effort and funds, in addition to small awards from organisations. You can help us take the work on into the future by giving a donation, of any size, that we can use to help purchase essential tracking devices (a geolocator costs about £100 +VAT, and can be used to track an individual bird’s migration and pinpoint the timing of its key life-history events for several years), artifical nest boxes, or pay for boat fuel needed to visit the colonies. If you are interested in donating to our Balearic shearwater project you can do so by clicking here