Blog by Dr Allan Perkins, Senior Conservation Scientist, RSPB Centre for Conservation Science
Working for the RSPB’s Centre for Conservation Science has given me some amazing experiences over the years, and none more so than the ten weeks in 2014 I spent camping on Mousa, a small uninhabited island off the southeast coast of mainland Shetland.
Uninhabited by humans that is, as the island is home to the UK’s largest colony of European storm petrels (c.12,000 pairs), along with other iconic northerly seabirds such as Arctic and great skuas, Arctic terns and black guillemots, as well as both grey and common seals, and otters. The aim of that trip, accompanied by my RSPB colleague Chris Bingham, was to undertake night-time research on the storm petrels, to see whether we could develop a better method for counting them. Findings from the study have just been published online in the ornithological journal Ibis, accessible here.
A fantastic nocturnal spectacle
European storm petrels (Hydrobates pelagicus) are small and elusive seabirds that feed far out to sea during the day, and only come ashore to their breeding colonies under the cover of darkness. They breed on rodent-free islands from Iceland to the Canary Islands, and spend the winter roaming the seas off southern Africa. At the last count, the British Isles held around 83,000 pairs in 95 surveyed colonies, approximately 17% of the biogeographical population of the subspecies H.p.pelagicus. Storm petrels (or alamootie, to give them their Shetland name) nest in burrows beneath rocks, scree and boulder beaches, and within the base of dry-stone walls. On Mousa, several hundred pairs also nest inside the stone walls of the island’s famous Iron Age broch, a 13 m high tower.
From late May to mid July, guided night-time trips with The Mousa Boat allow visitors to witness the fantastic spectacle of storm petrels flying around the broch as they enter and leave their nesting chambers, and hear the cacophony of eerie calls coming from almost every wall and boulder patch – a truly unforgettable experience!
It is these nocturnal, burrow-nesting habits that make storm petrels notoriously difficult to census. Current methods utilise ‘playback’ surveys, which involve playing a recording of the ‘purring’ song at potential nest sites to elicit a response. However, even when burrows are known to be occupied, response rates are typically low and are known to vary among colonies and years, leading to imprecise population estimates. For example, the playback census on Mousa in 2008 gave a mean estimate of approximately 11,800 pairs, but applying 95% confidence limits gave an estimated range of 8,100–17,700 pairs. With such an imprecise estimate, it is difficult to detect population change between censuses.
Photo: Mousa is a small uninhabited island off the southeast coast of mainland Shetland and home to the UK’s largest colony of European storm petrels.
New method for surveying
In recent years, thanks partly to the flourishing market for home security systems, technological advances have led to significant improvements in the capability of video cameras to record high quality images at night, using infra-red illumination. Equipment costs have also come down, potentially offering an affordable alternative to playback that could improve the precision of population estimates.
So our task was to test the use of infra-red video cameras for filming storm petrels entering and leaving nest sites, and to compare counts extracted from the video footage with counts made from both playback and night-time listening surveys. We mounted cameras on poles 2–4m above the ground, overlooking study plots in occupied breeding habitat (10 walls and 10 ‘natural’ sites). We filmed each plot ten times from mid-June to early August between 23:45 and 02:15, giving almost 450 hours of footage (click here to see examples). Despite some challenging conditions at times (eg. fog!), image quality was generally good enough to see birds entering or leaving their burrows.
Night-time listening surveys involved carefully crawling around the study plots on hands and knees, with ear almost literally to the ground, to locate and record burrow entrances from which storm petrels were calling. Ten such visits throughout the study period gave us an independent assessment of the number of apparently occupied sites within each study plot. For comparison, a daytime playback survey of the study plots was carried out in late July/early August, following standard census protocols.
What’s it like, working with storm petrels at night?
First of all, the sound is incredible – a constant chatter of purrs, trills and chirrups seemingly coming from all around you. Then there’s the smell, a musty oily aroma rising from the ground. Finally, watching these amazing little birds flying around almost bat-like is a real treat, especially in windy conditions when their mastery of flight is wonderful to watch and admire.
On misty nights it can be a little spooky, especially when working amongst ruined buildings with a calling storm petrel circling around you unseen in the darkness, and very rarely when one crashes into your head! Old tales of islands haunted by unearthly creatures are completely understandable. Fond memories also include sunrises over the West Pool on beautiful calm mornings, with a soundtrack of howling seals, screaming tirricks (Arctic terns) and singing skylarks, and then collapsing into bed at 4am with an extremely loud wren beside the tent singing you to sleep!
Among the most memorable moments there was a piece we did with The ONE Show and huddling around a radio in the tent listening to Germany beat Brazil 7-1 in the FIFA World Cup semi-final (one of the greatest ever shock football results). Birding highlights were brief visits by a singing marsh warbler, grey-headed (yellow) wagtail, wood sandpiper and little stint. Less happy memories are of carrying heavy kit, water containers and shopping bags around the island (base-camp was 1km from the jetty, but on the plus side we did have a wheelbarrow!), cold, wet and windy nights inside a noisy flapping tent, end of night retrieval of filming kit whilst falling asleep on your feet, and the occasional plague of slugs and midges.
Of course, filming hundreds of hours of footage left us with the huge task of reviewing it, and a sampling approach was necessary. With the invaluable help of five volunteers (a big thank you to Nathan, Ruth, Jenny, Laura and Anna), we reviewed one hour of footage per plot per night (200 hours in total) to extract counts of birds entering and exiting nest sites, and overall, 2064 entries/exits were detected. Analysis of the data then compared the number of apparently occupied sites determined from infra-red filming with intensive night-time observations, and with playback.
Photo: Storm petrel are small and elusive seabirds that feed far out to sea during the day, and only come ashore to their breeding colonies under the cover of darkness, by Ed Marshall (rspb-images.com)
Did it work? Well, yes, at least partially
We’ve shown that infra-red filming is an accurate and effective census method for storm petrels nesting in natural habitats such as boulder beach and scree. It is also probably less intrusive as a census method than playback and other methods such as mark-recapture.
However, it worked less well for walls, image quality was poor on nights with fog, rain or strong winds (not infrequent in Shetland in summer!), and the filming equipment sometimes failed. Even in natural plots, high levels of between-night variability in recorded activity meant that filming must sample many plots over several nights to generate reasonably precise population estimates. Extracting data retrospectively from the video footage was also labour intensive.
Therefore, our overall conclusion was that infra-red filming is currently costly and inefficient relative to playback, and population estimates were only marginally more precise. Further technological improvements will undoubtedly increase the viability of infra-red filming in future, but until then, it is unlikely to replace playback as the main census method. Instead, we recommend that infra-red filming should be considered as a method complementary to playback, by enabling survey coverage of sites that cannot be surveyed safely using playback transects (eg. unstable scree slopes above cliffs), or where disturbance is a concern.
The publication of this study (and recently, another related study to improve the playback method for Manx shearwaters) is timely because it will inform storm petrel surveys in a new Britain and Ireland seabird census that RSPB and partner organisations are currently undertaking. ‘Seabirds Count’ is being led by JNCC on behalf of the Seabird Monitoring Programme (SMP) partnership, and aims to count all breeding seabirds in the Britain and Ireland. This census aims to provide a critical update of the status of our internationally important seabird populations, and includes inland colonies of gulls, terns, skuas and cormorants as well as coastal colonies of all 25 seabird species that breed around our shores. Seabirds Count began in 2015 and, subject to funding, aims to complete over the next two years, but the task is huge. As with the previous Britain and Ireland census (‘Seabird 2000’), considerable help from volunteers will be needed to complete the colony counts during the summers of 2018 and 2019. If you are interested in participating, please keep an eye on the JNCC website in the coming weeks for further information, or email SeabirdsCountCoordinator@jncc.gov.uk
Gough Team 63 left Cape Town on the 7th September, it felt like an age the team being on the SA Aghulas II. After nearly a week of being on the boat, Tristan da Cunha is insight, here to offload the Tristan passengers and the cargo that are onboard, also need to load up equipment for Nightingale Island. This is a 60 hour stopover.
Photo: Courtesy of Jaimie Cleeland - Kate taking in the view of Tristan da Cunha
Photo: Courtesy of Jaimie Cleeland - Helicopter slinging cargo to Tristan da Cunha
Photo: Gough Team 63 on Tristan da Cunha
Off to explore Tristan da Cunha taking advantage of the hours there before heading back on the boat to Nightingale Island.
Photo: Courtesy of Jaimie Cleeland - Fabrice and Kate off on foot on Tristan da Cunha for a day of sightseeing.
A good day on Tristan da Cunha. Back on the boat for a day to Nightingale Island to offload personnel and equipment.
Photo: Courtesy of Jaimie Cleeland - Kate on the monkey bridge on the rough seas.
Photo: Courtesy of Jaimie Cleeland - Southern Giant Petrel flying by Nightingale Island.
On every misty day staring at the horizon waiting, longing for the view to change, finally on the 16th September an island in the distance emerged, Gough Island insight - Land ahoy!
Photo: Courtesy of Jaimie Cleeland
The stern deck of the SA Aghulas II while on route to Gough Island.
Photo: Courtesy of Jaimie Cleeland .
Grabbing a quick chance to do some bird watching.
Photo: Courtesy of Jaimie Cleeland - Kate and Fabrice bird watching on route to Gough Island
Photo: Courtesy of Jaimie Cleeland - View of The Glen - Gough Island.
Photo: Courtesy of Jaimie Cleeland - Kate in front of The Glen at Gough Island
Now they just need to disembark and offload all the cargo...........................................
The Gough Island Restoration Programme is being carried out by the RSPB in partnership with Tristan da Cunha, BirdLife South Africa and the Department of Environmental Affairs in South Africa.
The programme is part-funded by the RSPB, the UK government, the National Fish and Wildlife Foundation and other generous individuals and organisations.
If you would like to support our efforts to save the Critically Endangered Tristan albatross and Gough bunting, please contact John Kelly, or you can donate using our online form
Blog by Dr Rebecca Jefferson, Senior Conservation Scientists, RSPB Centre for Conservation Science
In late June I headed to Bonn in Germany for the European Conference on Biodiversity, Human Health and Climate Change. Conferences cost time and money, so going to a conference has to deliver rich rewards to be a worthwhile return on the investment. This one certainly delivered. Linking these three huge topics is no small ambition, so there was plenty discussion to be had, led by a diverse suite of excellent speakers.
The reason this was a standout conference for me to attend was the relevance to my research themes; I lead our work on the people side of conservation and that includes several projects on biodiversity and human health. This includes our project investigating the effects of growing up in a housing area with biodiversity enhancing features and understanding the connections between marine biodiversity and wellbeing.
There was a packed agenda of speakers, including keynote presentations from across Europe, workshops with a series of themed presentations and discussions to answer key questions, and a diverse range of posters.
Photo: The RSPB is working with Barratt Developments and Aylesbury Vale District Council to set a new benchmark for wildlife-friendly housing.
I presented my work in a workshop on “Planning and managing urban green spaces for health and biodiversity in a changing climate – Concepts, experiences, practice”. My presentation gave the NGO view point on working across the biodiversity and human health sectors, within the context of climate change. I highlighted some of the ways RSPB is engaging with biodiversity and human health, including our work on reserves with people with mental health conditions and our housing work. I reviewed some of the challenges and opportunities to this joined field of work: on the challenges side, it could be argued that the nature conservation sector has got enough to do responding to the biodiversity crisis, therefore why are we making things more difficult by adding human health challenges to the mix? However, there are clear opportunities – if nature conservation isn’t engaged in this debate, then how do we know biodiversity is being fully understood? I also feel that much of our work has a real or potential wellbeing benefit for people, and we should be aware of that even if it is not always the driving force behind our action.
There were too many presentations to describe them all here, but a few stick in my memory. Wouter Poortinga presented on public perceptions of climate change. Public perceptions research is close to my heart having formed a significant part of my PhD research and being a current theme of work. Wouter’s presentation on the breadth of climate change perceptions research, the applications to understanding public discourse and the essential ability to see subjects of imperative from someone else’s perspective were inspiring. He urged the audience (as did many others) to pick up the baton for biodiversity engagement.
Catharine Ward Thompson presented a fascinating range of research, particularly on the elderly and biodiversity/green space access. She was honest about the remaining research questions, and gave every confidence of being keen to address them. Research articles are a good way of recording and sharing science but there is nothing like seeing the originator of the research describe their work with the passion and honesty which you get in a conference presentation.
All in all, my main key take home messages were:1. the need to engage society with the biodiversity challenge is urgent and will be more complex than engaging people with climate change; 2. equity of access – to greenspace and therefore the benefits it delivers; 3. interactions with biodiversity aren’t always good for our health (think mosquitoes);4. the links between health and biodiversity are complex and not fully understood but they cannot be ignored by conservation.
The recurring themes were urgency, equity and the need for continued enquiry, some of which have strengthened ideas I already had and others gave me a renewed perspective. What I have learnt and heard at the conference will influence my work: I now have a greater breadth of resources to draw from to inform development of my current projects, and they add to my thinking about how biodiversity, human health and climate change interlink and how our science and practice can be influenced in the future. Thanks to the organisers and all the speakers for a fascinating event which has given me plenty of food for thought.