British Birds Volume 110 rts Birds British Great bird reserves:birdGreat RSPB uut21 o.1 2–492 425– • Vol.110 • 2017 August Guillemot eggs • Iberian Chiffchaffs Iberian • eggs Guillemot The Carl Zeiss Carl The Award2017 British Birds Established 1907, incorporating The Zoologist, established 1843 Published by BB 2000 Limited, trading as ‘British Birds’ Registered Office: c/o McPhersons CFG Limited, 23 St Leonards Road ISSN 0007-0335 Bexhill on Sea, East Sussex TN40 1HH www.britishbirds.co.uk Editorial Subscriptions & administration Roger Riddington Hazel Jenner Spindrift, Eastshore, 4 Harlequin Gardens, St Leonards on Sea, Virkie, Shetland ZE3 9JS East Sussex TN37 7PF Tel: 01950 460080 Tel & fax: 01424 755155 [email protected] [email protected] Editorial staff Roger Riddington (Editor), Design & production Caroline Dudley, Peter Kennerley Mark Corliss Editorial Panel Dawn Balmer, Ian Carter, [email protected] Richard Chandler, Martin Collinson, Mark Holling, Chris Kehoe, Stephen Advertising Menzie, Robin Prytherch, Nigel Redman, Hazel Jenner Roger Riddington, Brian Small, Steve Votier Tel: 01424 755155 [email protected] ‘News & comment’ material to Adrian Pitches Annual subscription rates [email protected] Individual subscriptions: UK – £60.00 Overseas (airmail) – £70.00 Rarities Committee Libraries and agencies – £110.00 Paul French (Chairman), Chris Batty, Subscribe by Direct Debit and David Fairhurst, Nic Hallam, Nigel Jones, save £5.00 off the above rates Micky Maher, Richard Millington, Mike Digital subscriptions £60.00 per year. Pennington, Richard Schofield, Steve Votier Single issues and subscriptions for Secretary Chas Holt, 307 St John’s Way, shorter periods also available. Thetford, Norfolk IP24 3PA; See www.britishbirds.co.uk/subscribe [email protected] Back issues Notes Panel available from www.britishbirds.co.uk Angela Turner (Chair), Will Cresswell, Ian Dawson, Jim Flegg, Ian Newton, Guidelines for contributors Malcolm Ogilvie See www.britishbirds.co.uk

British Birds is owned and published by BB 2000 Limited, the directors of which are Adam Rowlands (Chairman), Lizzie Bruce, Mark Holling, Stephen Menzie, Nina O’Hanlon, Adrian Pitches, Richard Porter and Chris Spooner. BB 2000 Limited is wholly owned by The British Birds Charitable Trust (registered charity No. 1089422), whose trustees are Bryan Barnacle, Neil Bucknell, John Eyre, Ian Newton and Richard Porter. Directors and trustees are volunteers who draw no remuneration.

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Front-cover photograph: Male Bearded Tit Panurus biarmicus, Minsmere RSPB reserve, , April 2006. David Tipling

British Birds Volume 110 • Number 8 • August 2017

426 BB eye Paul Jepson 430 News and comment Adrian Pitches 435 Great bird reserves: RSPB Minsmere Adam Rowlands

456 Vulgar errors – the point of a guillemot’s egg Tim Birkhead 468 The Carl Zeiss Award 2017 Paul French 476 Short papers 484 Notes 485 Reviews 487 Obituaries 489 Recent reports 491 My patch

This issue opens with a thought-provoking editorial on the rapidly changing position of photography in the British (and indeed worldwide) birding scene. We’ve been talking about the ‘digital revolution’ for more than a decade now, but Paul Jepson has produced a categorisation of the different forms of ‘photo-birder’ that reminds me of the iconic definitions of twitcher, birder and dude from Bill Oddie’s Little Black Bird Book in 1980. It’s not entirely coincidental that I’ve saved Paul’s article for an issue when regular readers might have been expecting to see another round of BB’s Bird Photograph of the Year competition. In fact, in the wake of last year’s 40th instalment, we decided that BPY had run its course. The award has covered perhaps the most remarkable 40-year period of bird photography, from a time when it was the province of a privileged minority, to a point where virtually everyone has some sort of camera, and the results each year are amazing. Nowadays, picking a single winner from a sea of excellence is almost impossible. More importantly, in order to continue to compete at the top table of photography competitions the necessary investment in sponsorship and administration is such that we felt our production resources were better focused on the core aspects of birding and ornithology that remain at the heart of BB. A cross-section of these – conservation, ecology and identification – are well represented in this issue. And there is still one competition – the excellent Carl Zeiss Award. As promised last month, the issue is brought to a close with ‘My patch’, written this time by a young birder. The unbounded optimism and enthusiasm of devoted patchworker Amy Robjohns shines through the pages. I was slightly alarmed to look back through my notebooks and find that my only previous visit to Titchfield Haven was around ten years before she was born – so it’s probably time I went back…

Roger Riddington

British Birds aims to: v provide an up-to-date magazine for everyone interested in the birds of the Western Palearctic; v publish a range of material on behaviour, conservation, distribution, ecology, identification, movements, status and taxonomy as well as the latest ornithological news and book reviews; v maintain its position as the journal of record; and v interpret scientific research on birds in an easily accessible way. © British Birds 2017 BB eye

Photography is transforming British birdwatching

One Sunday last July I strolled down to the counter-culture (and later punk) and the hide at RSPB Otmoor, one of my local appearance of a better-educated, more confi- birding patches in Oxfordshire. Five years ago dent youth with an interest in freedom, I might have entered an empty hide. Not justice, personal fulfilment and a willingness anymore. The place was packed with bird to embrace unconventional lifestyles. photographers, happily chatting as they As a cultural force, birding was at its peak waited patiently for the shot. in the 1970s and 80s. An eclectic mix of The make-up of British birdwatching is birders from around the country convened at undergoing a transformation. Scope-carrying ‘meccas’ such as Cley and Scilly, where they birders have been joined by big-lens bird discussed reputations, shared stories, planned photographers. Over the last three years I trips and developed a sense of fraternity and have been engaging bird photographers in common purpose, all given identity with an conversations to learn more about their ‘insider’ birder jargon. Birders created the motivations and birdwatching practices. bird-tour industry, founded bird information These conversations have helped me to posi- services and magazines, played a key role in tion my ‘birder’ mode of birdwatching and the development of international bird con- caused me to reflect on the history and future servation and introduced the term ‘twitcher’ of birdwatching as a hobby and vocation. into popular culture. Birding is a mode of birdwatching charac- Over the decades the practices, discourses terised by a focus on bird finding, rarities and and norms of birding – and by extension listing. It emerged during the 1960s and birdwatching – have become more for- 1970s from interactions between trends in malised. We observe birds at distance and ornithology and wider society. The rise of have collectively agreed to put bird welfare field ornithology in the 1950s led to the first and suppress conversations about rare establishment of a network of bird observa- breeding birds. Birders travel to see birds tories and recorders and the idea that bird- reported by bird information services, keep watching could contribute to the study of to designated trails and respect landowner bird migration and population trends. This wishes. Our birdwatching media publishes was an era when teenagers had time to fill material on a relatively narrow set of topics and purposeful hobbies were encouraged. (sightings, identification, birding sites, popu- There was a good chance that a teenager lation trends and conservation status) and showing an interest in birds would be gifted carries editorials framed by the views and an affordable pair of Zeiss binoculars (from agendas of establishment figures and conser- the DDR) along with a field guide and told to vation organisations. get out of the house! Roaming around Birding had youthful origins but it has searching for the species in the books and become institutionalised and settled. The ticking them off was the obvious thing to do. language of dipping, gripping, stringers, crip- It developed bird-finding skills, a sense of plers, value and phasing is fading. The birder avian scarcity and a desire to visit destina- start-ups of the 1980s – the information serv- tions where new species could be added to ices, bird-tour companies, clubs (e.g. OBC, one’s list. ABC and NBC) and conservation pro- At the same time, broadcasters were grammes – are ageing. increasing the amount of nature program- Mingling with, and now sometimes out- ming and aligning it with aspirational numbering, birders is a new type of bird- lifestyles and exotic travel in a bid to watcher – the bird photographer. Bird encourage people to switch from black-and- photographers have been around since the white to colour TV. All this went hand in days of Cherry Kearton (1871–1940) and hand with the optimism of the 1960s Eric Hosking (1909–1991) but birds are

426 © British Birds 110 • August 2017 • 426–429 BB eye tricky subjects to photograph and the cost of equipment, film and processing traditionally limited the numbers of bird photographers. All this changed with the rise of digital photog- raphy. Film became obsolete, the shift from mechanised to elec- tronic camera bodies enabled an array of new models with advanced capabilities, and the internet and social media made it easy to curate, publish, share and discuss photos. Once the initial outlay has been made on equipment, bird photographers Paul Jepson Paul can shoot away to their hearts 234. Photo-birders at Otmoor, Oxfordshire, August 2016. content at little cost. As a result, their chances of getting a satisfying shot have The fourth mode is amateur photography increased massively, and with this comes the with birds as subject. This practice is all possibility of learning the craft of bird pho- about composition, pose and lighting and tography and finding a rewarding and any bird will do, although some species are engaging hobby. In short, birds can be pho- clearly more photogenic than others – the tographed with an ease that was unimagin- Robin Erithacus rubecula and Goldfinch able little more than a decade ago. Carduelis carduelis, for example. A fifth In my efforts to understand the practices mode, which may be a subset of the above, is and motivations of bird photographers, photo-trophy hunting, which is motivated by I found that two questions opened up the desire to capture a classic shot of an insightful conversations. These were ‘What iconic species, for example a diving Common do you do with the photos you take?’ and Kingfisher Alcedo atthis or lekking Black ‘Were you a birdwatcher or photographer Grouse Tetrao tetrix. I have also met bird first?’ photographers who do nothing with their Responses to these questions revealed five photos and told me that they buy a new common modes of bird photography memory card when one is full. These are (http://bit.ly/2t0lXmE). The first two are photo-hunters. extensions of birding, which I call photo- Bird photography appears to be giving identification and photo-listing. Birders are new expression to older ways of engaging increasingly carrying cameras to capture with birds, in particular bird trapping (many photos as an aid to identification, especially bird photographers bait an area or perch), of groups which are difficult to identify, and bird hunting and egg-collecting. These were as a means of verifying a rarity find should all popular forms of purposeful birdwatching they be lucky enough to come across one. with rich knowledge practices that faded Some photo-listers are twitchers who are away during the late nineteenth and early starting over again, others are new to bird- twentieth centuries as wild bird populations watching and have embraced the practice of declined and British society came to view the listing because it offers a focus and purpose persecution of wild birds as unacceptable. for their photography. Digital photography captures, shoots and A third mode of bird photography is akin collects birds but transforms them into data to butterfly- or egg-collecting. I’ve met many rather than a corpse (or an eggshell). There- photo-collectors who are working to com- fore, it is reinstating these practices alongside plete quality collections of the different the practices of observation that were at the plumages of each British species or of their heart of twentieth-century birdwatching. favourite groups. The more I talk with bird photographers,

British Birds 110 • August 2017 • 426–429 427 BB eye

names of good birds seen over a weekend and their eyes will probably glaze over; show them photos and there is more likely to be interest, comments of admiration and even the occasional ‘cool’ comment. In our increas- ingly visual culture, those who add nature photos to the mix are appreciated. Bird photography also seems to promote sociality among birdwatchers. In Paul Jepson Paul the days before bird alert 235. Photo-birders on the Farne Islands, Northumberland, May 2013. services, birders had to the more I come to realise the depth and network hard to get the gen. The ‘owt about?’ richness of engagement with birds that a greeting prompted conversations and the digital ‘upgrade’ of these older practices grapevine helped forge friendships. The brings. As a young birder I was taught to advent of pagers, apps and texts has under- observe a new or unfamiliar bird carefully, to mined the need for birder-to-birder commu- note and sketch its identification features, nication and British reticence has reasserted write up my notes and dutifully submit its deadening presence. I am beginning to records to the county recorder. I was taught wonder whether the big lens fulfils a similar about birding sites and etiquette, a little on role to a dog in that it advertises common how to read the weather and something interests and experiences and offers some- about how to ‘work’ a landscape to find birds. thing for strangers to chat about without the Birding has massively enriched my life, but as need to get too personal. In addition, the a pastime I have found it lacking in three common practice of sharing bird photos via respects: it doesn’t promote prolonged Facebook or on birding blogs (where they are engagement with an individual bird; a credited) means that many bird photogra- birding excursion generates few follow-up phers meeting for the first time will have pre- evening activities; and it provides few entry introduced themselves online. points to my wider interests in society, the For me, the rise of bird photography and arts, and politics. the sight of so many new people out bird- Bird photography in its various guises watching is heartening. I believe that bird seems to offer a more prolonged, expansive photography has widespread appeal as a and perhaps sociable form of birdwatching. hobby and I predict that many more people Some bird photographers told me how they will take up the pastime and new bird-related engage with an individual bird for extended knowledge practices will emerge along with periods of time in an effort to learn its move- new enterprises. Given this, the birding com- ments and foraging patterns and predict munity will need to adapt to a future where where it might appear in shot of their heavy their way of birdwatching may be one of tripods and cameras. Others talked more many. And the managers of nature reserves about the digital image and the pleasure they and other natural areas will need to rethink found after the event editing the image visitor strategies to accommodate this new and/or sharing and discussing it on Facebook mode of birdwatching. or Flickr, seeing it published on a birding In my experience, birders and bird pho- blog or building those photo collections. tographers are generally getting along just Importantly, the bird photo communi- fine. Some birders grumble that photogra- cates something meaningful about our bird- phers flush and disturb birds and don’t abide watching hobby to others. Tell a friend the by their etiquette when larger groups

428 British Birds 110 • August 2017 • 426–429 BB eye assemble for a rarity or spectacle. However, of pay-for nature hides with an observation on the whole each is enriching the other. tower, like the one in Muritz National Many birders are also photographers and Park outside Berlin, as its centrepiece birders offer bird photographers information (http://bit.ly/2sm0pPy). Birding has a strong and outlets for publishing photos. Photogra- ‘nature as a public good’ mentality. While phers contribute photos to these outlets and many bird photographers agree with this always seem to have a fully framed shot to principle, they are also willing to pay for share of a bird that a birder has struggled to entry to the facilities and special places that see well. enable them to get the shot they desire. In my view, the problem and opportunity Nature hides are popping up across Britain lies with our birdwatching infrastructure, and 2017 hide day rates are £75 for the which has been built up over the decades to opportunity to photograph Common serve birders – observation via binoculars Kestrels Falco tinnunculus, £99 for and telescopes. Bird photographers operate Kingfishers and £150 for Black Grouse with different equipment and have different (http://bit.ly/2shs0X3). objectives. They want to get closer to birds The Kilnsea/Spurn landscape has out- and get shots at lower or different angles than standing bird photography assets in the form is possible from a conventional bird hide or of its wader roosts and migrant and passage trail. They are less concerned with scanning birds. Photographers are likely to pay good and picking birds up and more concerned money to get close to Spurn’s bird spectacles with the bird subject and its setting. and specialities. The Unimog could be used The changing make-up and identity of for photo-safaris and the community’s British birdwatching suggests a need for new growing population of retired birders could thinking and investment in visitor facilities, supplement their pensions with photo-bird and not just hides and trails. Bird photog- guiding. The observation tower would raphy is part of the socio-technological provide a panoramic view of the dynamic assembly that is shaping futures. If bird- Spurn peninsula and a world-leading viz-mig watching is to be a cultural force in the facility. It could carry communication and twenty-first century, our bird reserves will wifi masts opening opportunities for Spurn need to embrace developments and direc- to become an innovator in technology- tions in digital technologies. empowered nature interpretation and a The rift between Spurn birders and the mecca for new nature-based enterprises. Visi- Yorkshire Wildlife Trust prompted me to tors would pay (and probably queue) to think about how trends in birdwatching, climb the tower and revel in the photos they technology and society might be combined can capture and share with their smart- to modernise birdwatching along with visitor phones. engagement and financing. In brief, the YWT Bird photography represents more than a lost a focused point of visitor engagement new investment case and income stream for and an important income stream when a our cash-strapped reserves: it offers the 2013 tidal surge broke the road down to the opportunity for birdwatching to forge a new Spurn peninsula. It is constructing a new identity and shape new visions for bird con- visitor and training centre, part-funded by servation, public engagement and nature- the Humber Gateway offshore windfarm, as a based economies. means to engage visitors with the Spurn If we are bold and open to change, the environment and generate income for the future of British birdwatching is bright. Trust from new members, car parking, a café, Unimog safaris and events. Nature tourism Paul Jepson may also stimulate the local economy. Local birders object that the centre will destroy a Paul Jepson directs Oxford University’s MSc in Bio- location important to their engagement with diversity, Conservation and Management and is a Senior Research Fellow with the Smith School of this iconic birding landscape and residents Enterprise and the Environment. He is a former worry about the increased traffic. director of the BirdLife International Indonesia Pro- My thought experiment imagines a system gramme and chairperson of the Oriental Bird Club.

British Birds 110 • August 2017 • 426–429 429 News and comment Compiled by Adrian Pitches Opinions expressed in this feature are not necessarily those of British Birds

British Birds at the Birdfair

It’s that time of year again! The British Bird- while on the Saturday morning Martin watching Fair at Rutland Water is a firm Collinson of Aberdeen University (and vice- fixture on birders’ calendars and once again chairman of the BB Editorial Panel) will take BB will be at Birdfair, on 18th–20th August, us through the dark arts of DNA analysis in Marquee 3 (Stands 24–25). We’ve outlined in his ‘CSI: Birding’ paper in the expanded our presence at Birdfair this year January issue (Brit. Birds 110: 8–26). with three lectures by the authors of recent In addition, we are once again partnering papers in the journal. with the RSPB for an entertaining evening Adam Rowlands, the Senior Site Manager event entitled ‘The art of finding rare birds’, at RSPB Minsmere (and Chairman of the BB where the speakers are Ireland’s Killian Board of Directors), will be celebrating 70 Mullarney, and two east-coast stalwarts, one years of the RSPB’s flagship reserve to coin- from either side of the Humber , cide with our latest ‘great bird reserves’ Graham Catley and Mick Turton. Earlier on feature (see pp. 435–455). BB Trustee Ian Friday, BBRC chairman Paul French and TV Newton will be revisiting his popular paper naturalist Simon King will present the annual from the February issue, ‘In praise of Carl Zeiss Award for the best contribution to hedgerows’ (Brit. Birds 110: 77–91). His rarity recording in 2016 (outlined in detail lecture is on the Friday morning of Birdfair, on pp. 468–475). Here are the BB Birdfair highlights for your diary: Friday 10.30 Lecture Marquee 1: Ian Newton – Hedgerows 11.30 Lecture Marquee 2: Adam Rowlands – 70 years of Minsmere 17.00 Events Marquee: The BBRC Carl Zeiss Award 18.00 Events Marquee: RSPB Birders/British Birds – The art of finding rare birds Saturday 10.00 Lecture Marquee 2: Martin Collinson – CSI: Birding

England’s Mediterranean breeding season

Black-winged Stilts Himantopus himantopus young have fledged at RSPB Cliffe Pools, in in Cambridgeshire, Kent and Norfolk, Kent. Eurasian Spoonbills Platalea leucorodia in The RSPB tends to have a monopoly on Yorkshire, Cattle Egrets Bubulcus in rare, long-legged breeding birds as it has Cheshire and European Bee-eaters Merops created or nurtured most of the substantial apiaster in Nottinghamshire: the Mediter- reedbeds and other extensive wetlands in ranean weather of spring/summer 2017 has England. In 2017 on the Somerset Levels been reflected in the colourful and cosmo- there were seven nests of Great White Egrets politan breeding birds that have colonised alba, which produced 17 young, and new territory this year. five nests of Cattle Egrets, from which nine Pairs of Black-winged Stilts have reared young birds fledged. But two of the Society’s broods at several English wetlands this northern outposts also came under the spot- summer with the families at Potter Heigham light this year. in Norfolk and at RSPB Ouse Washes in The first breeding Cattle Egrets in Som- Cambridgeshire being particularly popular erset in 2008 followed the influx of winter with birders, while no fewer than seven 2007/08 and after another winter influx in

430 © British Birds 110 • August 2017 • 430–434 News and comment

2016/17, a pair has nested at RSPB Burton Mere Wetlands in Cheshire. Across the Pen- nines in West Yorkshire, Spoonbills have nested at RSPB Fairburn Ings, rearing three young. This is the first time Spoonbills have nested in northern England – and the first time on an RSPB reserve. (The colony at Holkham in north Norfolk, where Spoonbills first nested in 2010, is on land managed by .) It was sufficiently news- worthy for BBC Look North in Yorkshire to report the story, although they chose an image of the Neotropical Roseate Spoonbill P. ajaja to illustrate the story (something that would never happen on BBC Look North in the North East & Cumbria…). But, aside from Roseate Spoonbills, the most spectacular breeding visitors this summer have shunned the nation’s nature reserves: the flock of seven Bee-eaters that arrived in the East Midlands in June has taken up residence in a CEMEX sand and gravel quarry at East Leake on the Leicester-

shire/Nottinghamshire border. If they’re still Peter Beesley in residence in mid August, many Birdfair 236. European Bee-eaters Merops apiaster, visitors will no doubt stop off to see them. Hungary, May 2011.

Saving Paradise in the Pacific

Saving Paradise in the Pacific is the fundraising hours, three ships transporting hundreds of theme of this year’s Birdfair. Rat eradication tonnes of equipment and donated poison programmes on Pacific islands which are bait as well as 31 personnel from six coun- home to some seriously endangered species tries who made 12-day voyages to and from will be boosted by Birdfair funds. Vahanga, Tenarunga, Temoe, Kamaka, The work is already under way. Just two Makaroa and Manui, the six islands. years after efforts to rid French Polynesia’s David Beaune, Director of SOP Manu Acteon-Gambier islands of invasive (BirdLife in French Polynesia), said: ‘After mammals began, five of the six targeted extensive monitoring, a survey in April con- islands are now confirmed as predator free, firmed great success on five of the six islands. 1,000 ha in total. Early signs indicate that The project has more than doubled the rare endemic birds are recovering, including secure habitat for both the Polynesian the Critically Endangered Polynesian Ground Ground Dove and the Endangered Tuamotu Dove Alopecoenas erythropterus – once much Sandpiper Prosobonia parvirostris… both more widespread in the Pacific, but now species are increasing on the island of fewer than 200 individuals remain. Tenarunga, something that has not been pos- Steve Cranwell, BirdLife’s Invasive Species sible for decades.’ And there’s been a major Manager, said: ‘This bird’s remaining pred- spin-off for the human population too, with ator-free habitat was so small that without a doubling of their copra (coconut kernel) this intervention, a cyclone, prolonged production in 2016. drought or accidental rat or avian disease Not all rat eradication programmes are introduction could trigger extinction.’ successful, however. In 2011 the RSPB and The project required 165 helicopter flight partners attempted to eradicate Pacific Rats

British Birds 110 • August 2017 • 430–434 431 News and comment

Rattus exulans from Henderson Island in the individuals. A genetic study by Cambridge South Pacific. Some 75 tonnes of poison bait University and the RSPB established that were methodically dropped on a grid across there was no resistance to the poison, simply the 37-km2 island in an operation that cost that a handful of the rats had not been £1.5m. The eradication team left after three exposed to the bait. And from as few as 60 months satisfied that the entire population survivors the rat population had returned to had been exterminated. But in March 2012, a pre-eradication levels. You can read their single rat was spotted – and by the time a research paper in Royal Society Open Science repeat expedition arrived in May 2015, the at: http://rsos.royalsocietypublishing.org/ rat population had returned to c. 100,000 content/3/4/160110

Hen Harriers in decline across the UK

The depressing decline in England’s breeding illegal killing of those birds associated with Hen Harrier Circus cyaneus population is driven grouse-moor management in well documented, with just four pairs in northern England and parts of mainland 2016. Now the latest national Hen Harrier Scotland. Other pressures such as cold and survey has shown a decline across the UK: wet weather conditions over a number of from 633 breeding pairs in 2010 to 545 pairs breeding seasons, changes in habitat manage- in 2016, a drop of 88 pairs. ment and low prey abundance could all have Scotland remains the UK stronghold with had an impact on numbers throughout the 460 pairs, down from 505 pairs in 2010. UK. Wales has 35 pairs (down from 57 in 2010), RSPB Conservation Director Martin Northern Ireland 46 pairs (59 in 2010) and Harper said: ‘The latest figures back up a the Isle of Man (not part of the UK) has a continued trend that we have seen for more further 30 pairs (up from 29 in 2010). than a decade: Hen Harrier numbers are on Longer-term figures show a decline of nearly the decline throughout the UK. The illegal 40% since 2004 when there were 749 killing of this bird of prey is a significant breeding pairs in the UK, compared with the factor behind the diminishing numbers and a 545 found in 2016. large barrier stopping their recovery. Without The reason for the decline is likely to be a purposeful action from all, including govern- combination of factors that vary from region ments across the UK and the shooting to region. It is known that the main factor industry, we may see Hen Harriers once limiting the UK Hen Harrier population is again lost from more parts of the country.’

Hen Harrier Day 2017

Widespread anger at the continuing illegal fashioned march on Downing Street, well killing of Hen Harriers led to the first Hen there is one – on Saturday 12th August. A Harrier Day of action in 2014 with gatherings coalition of wildlife protection charities of birders and conservationists in Northum- is protesting about cruelty and crimi- berland, Lancashire and Derbyshire on the nality towards Badgers Meles meles, Foxes Sunday closest to the ‘Inglorious 12th’ – the Vulpes vulpes and Hen Harriers. Speakers start of the grouse shooting season. Each year will include Chris Packham, Mark Avery more events at more locations across the UK and Dominic Dyer of the Badger Trust. have been scheduled and this year’s events are The march will begin at Cavendish spread across two Hen Harrier Days – Square at 1.30 pm before heading down Saturday and Sunday 5th and 6th August. Regent Street, Pall Mall, around Trafalgar You can find a full list of events here: Square and down Whitehall, ending at http://henharrierday.org/2017-events.html Richmond Terrace opposite Downing And if you fancy a genuine old- Street.

432 British Birds 110 • August 2017 • 430–434 News and comment

Seabird feeding areas mapped for the first time

New research using five years of seabird GPS step forward in our understanding of seabird tracking data has estimated the areas of sea ecology. used by four of Britain & Ireland’s breeding Until recently, seabirds could be mapped at seabirds: Kittiwake Rissa tridactyla, Shag Pha- sea only using boats or planes, and that lacrocorax aristotelis, Razorbill Alca torda and couldn’t tell us which colony each bird was Common Guillemot Uria aalge. This comes as from because they can travel huge distances to UK administrations are considering the cre- feed. Using GPS tracking allows scientists to ation of protected sites at sea to safeguard key follow individual birds, revealing exactly seabird feeding areas, as well as planning future where and how far they go to sea to forage and fisheries policy for UK territorial seas once which colony they’re from. The results reveal outside the EU’s Common Fisheries Policy. seabird hotspots – where birds of different Seabirds are one of the most endangered species, from multiple colonies, gather to feed. groups of birds in the world, partly due to the The majority of these are concentrated in the impacts of climate change and fishing. The coastal waters of Scotland, highlighting the UK is home to internationally important pop- need for strengthened conservation to protect ulations of breeding seabirds so we have a our marine biodiversity. global responsibility to safeguard them. Ewan Wakefield, lead author of the Numbers of the two Red-listed species, Kitti- research, said: ‘For the first time, this study wake and Shag, have declined by 71% and provides us with a full map for each breeding 62% respectively in the last 25 years. Razorbills colony of the feeding areas for some of our and Guillemots are Amber-listed, meaning most important seabird species. That means they also require conservation action. we can now protect the places these birds During the five-year project, lightweight catch the fish they need to feed their hungry GPS tags were fitted to more than 1,300 adult chicks, securing the future seabird genera- birds from 29 different colonies between Fair tions of these amazing creatures. If we can Isle and Scilly. Results from the tracking data reverse seabird declines, we can be fairly sure show that the four species use at least 1.5 that we’re getting things right for the fish and million square kilometres of sea, an area other marine life below the surface of the three times the size of Spain. This is a major sea.’ Roger Roger Riddington 237. Shags Phalacrocorax aristotelis and Common Guillemots Uria aalge at RSPB Sumburgh Head, Shetland, June 2016.

British Birds 110 • August 2017 • 430–434 433 News and comment

Covert cameras capture Cypriot bird trappers

The irony has probably not been lost on the the expensive dish ambelopoulia, a plate of RSPB Investigations team: covert cameras have cooked songbirds. secured bird-crime convictions in Cyprus Guy Shorrock, RSPB Senior Investigations when video evidence of raptor killing in Scot- Officer, said: ‘We are delighted with the land is thrown out by Crown prosecutors. success of our collaborative work with the Eight men have been fined for intention- SBA police and immensely grateful for the ally and systematically killing wild birds, efforts of the officers we worked with. It was including Blackcaps Sylvia atricapilla and great to be able to apply methods we have other warblers, on a British military base in developed in the UK to help tackle the Cyprus. In autumn 2016, the Sovereign Base serious bird trapping problems on Cyprus. Area (SBA) police worked with RSPB Investi- ‘These fines are substantially higher than gations staff to install covert cameras at average and the long suspended sentence several illegal trapping hotspots on the (four months in jail suspended for three Eastern SBA. During seven operations, 19 years) puts two of the men in a very serious individuals were secretly filmed catching position should they decide to continue trap- birds in mist-nets strung between bushes. ping. We hope the sentences given by the The birds were then killed with knives before courts will deter the trappers from using the the bodies were tossed into bags. This is the Base Area.’ first time this method of surveillance has Martin Hellicar, Director of BirdLife been used by the SBA police to catch illegal Cyprus, was also delighted with the outcome trappers. Following the joint RSPB/police of the collaboration, and added: ‘At the same operation, eight men were sentenced in June time, we will continue pushing hard for with fines totalling €13,800. action against law-breaking restaurants A report published in March revealed that serving trapped birds in the Republic and an estimated 800,000 birds were illegally also with our education efforts in schools killed on the Eastern SBA in 2016. The birds and beyond, with the aim of reducing the are caught to be sold to local restaurants for demand that drives the bird killing.’

British Birds donates a record £15,000 to conservation

The British Birds Charitable Trust has around £5,000 each year. The BB Trustees donated more than £40,000 over the past six then dispense this money as small grants. years to conservation and educational proj- In 2017 we are in the unprecedented posi- ects. Projects supported have ranged from rat tion of trebling the amount available for con- eradication on Pacific seabird islands to satel- servation/education grants to £15,000. This lite-tagging of Eurasian Cuckoos Cuculus follows greater than expected circulation for canorus. You can see the full list here: BB, coupled with very tight control of admin- https://britishbirds.co.uk/about/british-birds- istrative costs. We will shortly be opening charitable-trust applications for conservation grants for 2018. We also make grant awards to young A downloadable form will be available on our birders (aged 16–21) every year to help them website and we will publicise this via further their ornithological interests. The the journal, our e-newsletter and grants are funded by any surplus generated social media. from sales of BB, which typically amounts to

For extended versions of many of the stories featured here, and much more, visit our website www.britishbirds.co.uk

434 British Birds 110 • August 2017 • 430–434 Great bird reserves RSPB Minsmere Adam Rowlands Richard Allen Richard Island Mere, Minsmere

Abstract Minsmere, which celebrated its 70th anniversary as an RSPB reserve in 2017, has been an inspiration to naturalists and birdwatchers through its variety of habitats and species, its role in saving some of the UK’s most iconic breeding birds and the sense of space, peace and connection with nature that it provides. The essence of Minsmere was perhaps best captured by Simon Barnes: ‘Minsmere has a quality of vividness. It is a place that opens your eyes and ears, your heart and mind to birds: and to everything else that lives as well. There is a quality about Minsmere that inspires delight in life, all kinds of life: wildlife of every sort and, as an added bonus, your own life as well. The place is almost outrageously life- enhancing.’ (Flying in the Face of Nature, 1992)

Introduction lowland acid grassland, lowland heath, sand RSPB Minsmere lies on the Suffolk coast, dunes, shingle, coastal grazing , coastal roughly equidistant between the coastal , fen and reedbed. Offshore lies Sole towns of Southwold and Aldeburgh. It is part Bay, which forms an important component of a mosaic of land, stretching from the Blyth of the Outer Thames SPA and holds large Estuary in the north to the Alde Estuary in numbers of wintering Red-throated Divers the south, which is managed sympathetically Gavia stellata. Key species on the reserve for nature conservation. include breeding Eurasian Bittern Botaurus The Minsmere reserve covers 1,000 ha stellaris, Marsh Harrier Circus aeruginosus, (2,500 acres) and encompasses a wide range Stone-curlew Burhinus oedicnemus, of habitats including woodland, scrub, Recurvirostra avosetta, European Nightjar

© British Birds 110 • August 2017 • 435–455 435 Rowlands

within the Suffolk ich unw To D Coast & Heaths To Blythburgh Area of Out- Road standing Natural Beauty; it forms part of the Mins- mere to Walbers -

NATIONAL wick SSSI, Ramsar, TRUST DUNWICH SPA and SAC sites; HEATH and it is one of five sites in the UK awarded the Euro-

Private Road pean Diploma for Protected Areas designation. Only the restored arable H V areas lie outside oad T 2 1 these designations, Private R 4 H 3 H but they are NORTH ISLAND MERE H THE H afforded some pro- H SEA SCRAPE tection in relation

H H to their breeding bird interest. The New Cut The Sluice History

To Leiston The land that cur- Abbey Chapel ruin rently forms the reserve was farmed 0 1 km To as lowland

Woodland and arable land H Hide Viewpoint Family Discovery Zone & Scrub until the outbreak Water Heathland V Visitor centre Visitor trail 1 Warden’s office 2 Wet grassland Acid grassland T Toilet Footpaths/bridleways The Discovery Centre of the Second 3 The Wild Zone Sand dunes and Reserve border World War. It was shingle Reedbed/Fen Parking 4 The Wild Wood Adventure

Jenny James also a shooting Fig. 1. Minsmere RSPB reserve, from Suffolk’s Wildlife Coast: a guide to the estate managed by RSPB nature reserves in coastal Suffolk. the Ogilvie family and many of the Caprimulgus europaeus, Bearded Tit Panurus areas of deciduous woodland on the reserve biarmicus, Woodlark Lullula arborea and were planted over 100 years ago as part of the Dartford Warbler Sylvia undata. In winter shooting management. the site supports a small wintering popula- The low-lying marshes north of the New tion of Bewick’s Cygnus columbianus and Cut were flooded in the spring of 1940 as Whooper Swans C. cygnus together with part of wartime defences to prevent an White-fronted Anser albifrons and ‘Tundra armed invasion of the east coast. During the Bean Geese’ A. fabalis rossicus (during the day war, the army occupied Minsmere and used the geese tend to spend time feeding to the large areas of the heathland for military south of Minsmere, at the RSPB North manoeuvres, including the ‘Kruschen’ exer- Warren reserve) and Smew Mergellus albellus cise (Liddiard & Sims 2013) as part of prep - (in declining numbers). arations by the allied forces for an invasion of Minsmere’s remarkable diversity of habi- continental Europe. The fact that Minsmere tats and wildlife has resulted in a whole suite was not drained after the war is a great credit of designations, which afford the majority of to the Ogilvie family, who resisted pressure the site the highest level of protection: it sits to return the marshes to agricultural

436 British Birds 110 • August 2017 • 435–455 Great bird reserves: Minsmere production. Geoffrey Dent had been world). Bert quickly realised that ecological discussing the potential of the site to become succession was putting at risk the continued an RSPB reserve from the late 1930s and a survival of many of the most important conditional agreement was signed on 25th species on the reserve. He demonstrated that April 1947, a month before the discovery of reed encroachment was threatening the nesting . remaining areas of coastal , and that Owing to its great diversity of birds, Mins- gradual loss of bare ground on the heathland mere became a regular destination for keen was jeopardising rare breeding birds such as birdwatchers in the post-war years, including Stone-curlews. With regard to the lagoons, he Eric Hosking who captured a fine range of set about his ambitious plan to restore an images of birds at the site during the 1950s area landward of the dunes, the now-famous and 1960s. Max Nicholson played a part in Minsmere Scrape (which Mike Everett has the establishment of the reserve and credited pointed out should be spelt with a capital the arrangements at Minsmere for sup- letter since it is the ‘type specimen’!; Brit. porting the conservation element of the 1949 Birds 95: 200). Over the course of several National Parks and Access to the Countryside years in the early 1960s, Bert used bulldozers Act, which established the Nature Conser- and voluntary labour to lower the land levels, vancy and the legal protection of National create islands and install sluices, with the Nature Reserves and SSSIs. objective of attracting breeding terns and Bert Axell was appointed as the Minsmere passage waders. He also created new public warden in 1959. Bert was an imposing force access to the Sluice, providing a circular route in terms of practical nature conservation around the Scrape and enabling access to (Brit. Birds 95: 200, 97: 397–399), and his hides in the north, south, east and west. Bert’s move from Dungeness, in Kent, revolu- vision was to create the ‘Wembley Stadium’ of tionised the management of the site (and in birdwatching; at the time, he was encouraged due course other sites around Britain and the by colleagues at RSPB headquarters to keep Mike Page Mike 238. A bird’s-eye view of the Minsmere Scrape in February 2005, showing the extensive areas of open water that were created in the adjacent reedbed to enable the recovery of the Eurasian Bittern Botaurus stellaris population. The extensive areas of heathland, woodland and acid grassland are also visible in this image while along the dunes on the shoreline you can make out the line of concrete anti-tank blocks that were installed in May 1940 at the same time as the marsh was flooded as part of wartime defence measures.

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the storm suggested an alternative course of action. The storm had opened up areas of conifer plantation in the neighbouring Forestry Commis- sion estate in Dun - wich Forest (and also in Tunstall and Rendlesham Forests to the south). These areas were quickly recolonised by Woodlarks, which had been lost from the reserve in the 1960s. The objec-

RSPB Minsmere archive tives for the newly 239. Bert Axell, examining his skin collection at Minsmere, in 1963. purchased arable Bert was an instrumental figure in the development of Minsmere and land were therefore of conservation in the UK and beyond. changed and feasi- this vision to himself, since it was perhaps bility trials for restoring heath and acid grass- not fully in keeping with the views of local land in these areas began. For more planners. information about the reserve at this time, More than 50 years later, the Scrape readers are referred to Flying in the Face of remains one of the birding highlights of a Nature: a year in Minsmere bird reserve visit to Minsmere. The principles behind the (Barnes 1992). Scrape have influenced wetland management Geoff Welch was appointed Minsmere at nature reserves around the UK, as well as Manager in 1991, following Jeremy’s retire- in Malta, Malaysia, Hong Kong and other ment and took a leading role in this habitat places around the world. For further details creation work. This provided a significant of the reserve’s development during this contribution to the Government’s BAP period, see Minsmere: portrait of a bird reserve targets for creating lowland acid grassland (Axell 1977). and won an Environment Agency Pioneering Bert retired in 1975. His successor was Biodiversity Award. It has provided habitat Jeremy Sorensen, who presided over the for both Stone-curlews and Woodlarks to RSPB’s purchase of Minsmere in 1977 (until return to breed at Minsmere and is also then, the organisation had been a tenant of important for a range of scarce invertebrates, the Ogilvie family). Ten years later, the ‘Great especially ground beetles. The creation of Storm’ of October 1987 led to the loss of heather headlands through the application of 3,000 trees at Minsmere in a single night. The sulphur to acidify the soil and seeding with reserve became inaccessible for a fortnight heathland cuttings has also linked up areas of and everyone on site worked to clear trees dwarf-shrub heathland and enabled Silver- along the access route. It was initially consid- studded Blue Plebejus argus butterflies to ered that this would have a devastating consolidate their populations (see Ausden & impact on the reserve’s woodland wildlife, Kemp 2005 and Ausden et al. 2010). and in the subsequent years tree-planting During the 1990s, the focus of attention schemes were considered and in some places switched to the reedbeds and research on the implemented. A large-scale planting scheme declining Bittern population. The existing was contemplated when areas of arable land reedbeds were managed to benefit Bitterns within the present reserve boundary were and the grazing marshes south of the reedbed purchased in 1989; yet one of the impacts of on the North and South Levels, also used by

438 British Birds 110 • August 2017 • 435–455 Great bird reserves: Minsmere

Bitterns, were purchased. The North Levels tation encroachment, maintain water levels have been restored to support areas of exten- and ensure that the islands continue to sive reedbed, interspersed with areas of sea- attract breeding birds. In the last decade, the sonal inundation and wet grassland, while lagoons have been compartmentalised by the the South Levels were initially managed as installation of low earth bunds. This allows extensive lowland wet grassland. sections of the Scrape to be dried out (‘fal- lowed’) on a rotational basis, every five years Current management or so. The fallowed areas are allowed to vege- The key objectives of the current manage- tate over and are then reflooded, providing ment regime at Minsmere focus on the nutrient input to benefit populations of wetland, heathland and acid grassland habi- benthic invertebrates and reduce fish popula- tats (Rowlands et al. 2015). Water levels are tions, creating more food for wading birds managed by multiple sluices throughout the and wildfowl. Ground predators are excluded wetland habitats. All of these drain by gravity, from the Scrape by an electrified wire-mesh eventually emptying into the via fence. This was first installed in the winter of the main sluice at the seaward end of the 1988/89 in response to declining Avocet New Cut. There is also the facility to intro- productivity. The design was enhanced in duce sea water via this sluice and this is used 2014/15 to keep out Badgers Meles meles after to control salinity on the southern areas of they were found to be significant predators of the Scrape and to create brackish to fresh- ground-nesting birds on the Scrape. water transition zones across the South In recent years a more proactive manage- Levels. Dams and sluices prevent saline ment regime has been introduced on the incursion to the reedbed, protecting fish pop- grazing marshes of the North and South ulations and maintaining the food supply for Levels, with water levels adjusted seasonally. Bitterns, while ditches are cleared mechani- In most years the Levels have been exten- cally on a long-term rotation of approxi- sively flooded in the winter and then allowed mately 7–10 years. This provides habitat for to dry out through the spring and summer, wildfowl as well as ideal conditions for although in wetter years shallow floodwater wetland plants and invertebrates. has been allowed to remain until midsummer Vegetation is removed from the wetland and in drier years it is drawn down more habitats by a combination of mowing, rapidly. Most recently, this has been com- grazing and excavators, creating bare ground bined with more active management in the on the islands of the Scrape. The lagoons reedbeds too, with areas drained and grazed require annual management to control vege- by Highland cattle or Konik horses during David Tipling David 240. Minsmere North Marsh and Scrape, May 2008. This is a classic view across the reserve, looking south from neighbouring to Sizewell B nuclear power station in the distance.

British Birds 110 • August 2017 • 435–455 439 Rowlands Jon Evans 241. Female Eurasian Bittern Botaurus stellaris at Minsmere, March 2014. Foraging Bitterns often provide close and memorable views at the Bittern and Island Mere hides in spring. Such views enable males, with a blue flush to the lores, to be distinguished from females. Studies of the Minsmere Bittern population provided vital evidence to support the conservation recovery of this species in the UK.

the summer before they are reflooded and used to seed new areas of heather heathland the reed allowed to re-establish. This ‘setting on the headlands of the acid grassland rever- back’ of ecological succession is designed to sion areas. European Gorse is also cut and provide habitat for species that colonise these coppiced on rotation, providing nesting transitional and early successional habitats. habitat for birds. Areas with short, dense The extensive grazing on areas of shallow gorse have proved more successful at gradient on the edge of the reedbed has also retaining Dartford Warbler territories fol- allowed a transitional ‘blue-zone’ to develop lowing cold winters, with the birds more (White 2009) – a productive area of open likely to survive freezing conditions when the water between the standing reed and the shelter of dense gorse is available. Studies on grassland shore, which in Scandinavia is con- the heathland during the 1970s and 80s sidered to offer extremely rich feeding habitat (Berry 1979; Berry & Bibby 1981; Burgess et for waterfowl and herons. al. 1990) established the habitat requirements The heathland areas are managed to of Nightjars and recommended carrying out prevent encroachment by trees and European intervention management. This involved cre- Gorse Ulex europaeus, which are removed ating woodland glades adjacent to heathland mechanically or by grazing, while Bracken to increase the availability of edge habitat, Pteridium aquilinum is controlled mechani- most favoured for nesting and foraging, cally or with chemicals. The dwarf-shrub while small (1 m × 1 m) patches of heather community is dominated by Common were cleared at the base of small Silver Birch Heather Calluna vulgaris, Bell Heather Erica Betula pendula trees to provide bare ground cinerea and Western Gorse U. gallii with for nest sites. Nightjar numbers duly recov- localised Cross-leaved Heath E. tetralix in ered in response to these initiatives. damper areas. Areas of heather are managed The provision of bare ground (using by periodic cutting and removal to ensure a mechanical rotavators) is also important diverse age structure. The cuttings have been within the dwarf-shrub heathland as well as

440 British Birds 110 • August 2017 • 435–455 Great bird reserves: Minsmere on the neighbouring acid grasslands. It pro- beach and the shingle and sand is being vides habitat for ground invertebrates, annual allowed to roll back (redeposit) towards the plants and feeding sites for Stone-curlews and freshwater marsh at the northern end of the Woodlarks, while larger areas are used by reserve. Stone-curlews for nesting. Adjacent plots are cultivated on a biannual basis and the birds Birds prefer areas that have been cultivated the pre- The size of the reserve, combined with the vious year. Stone-curlew productivity has wide variety and significant extent of rare (at benefited from the provision of temporary least in lowland England) habitats con- anti-predator fences around cultivated plots, tributes to Minsmere’s immense biodiversity, supplemented by Fox Vulpes vulpes control. with nearly 5,800 species of plant and animal The acid grassland is grazed by sheep and recorded. This includes 342 bird species, with Rabbits Oryctolagus cuniculus, maintaining a up to 230 recorded annually and up to 100 short sward, which is important for foraging species breeding each year. A grand total of Stone-curlews and Woodlarks. 136 species have bred on the reserve. A suite Habitat restoration has also been a key of totemic breeding birds have thrived in element elsewhere on the heathland, with the response to targeted management, including removal of encroaching Silver Birch and Bittern, Stone-curlew and Avocet. In the Scots Pine Pinus sylvestris. The former spread century or so prior to the Second World War into previously open habitats following the there were some significant differences from departure of the military, the abandonment the birdlife that can be found nowadays. Bit- of grazing and other traditional land-man- terns were not found at Minsmere until the agement practices, and the decimation of the 1940s and the Marsh Harrier was the rarest Rabbit population following an outbreak of of the three harrier species. Montagu’s myxomatosis in the 1950s. Recent efforts Harrier C. pygargus was the harrier seen most have focused on the removal of same-aged regularly during this period, with birds stands of birch trees from this period, attempting to breed on the heath, but appar- followed up by ground works and sustainable ently they were frequently shot (according to management strategies, such as grazing, to Ogilvie’s journals). Stone-curlews were more restore and maintain open habitats. These widespread breeders in the area at this time. benefit Nightjars and Woodlarks, and in time The flooding of the marshes in the 1940s will provide habitat for Dartford Warblers. allowed the formation of reedbeds and The woodland at Minsmere is largely lagoons, which in turn attracted Bitterns and managed through non-intervention. Fallen Avocets to breed. timber is usually left untouched, while dead limbs and snags are not removed unless they are a risk 14 to visitors. A rotational scrub 12 management programme has 10 recently been introduced to main- tain an appropriate structure for 8 key nesting species such as 6 Common Nightingale Luscinia 4 megarhynchos. booming males no. 2 The dunes and the shingle ridge are also managed by non- 0 60 64 68 72 76 80 84 88 92 96 00 04 08 12 16 intervention, but temporary exclo- sures are employed to prevent Fig. 2. Annual counts of booming male Eurasian Bitterns trampling of the internationally Botaurus stellaris at RSPB Minsmere, 1959–2017. This species important communities of shingle was recorded breeding from at least 1948, but accurate numbers were not reported prior to the period shown. flora and disturbance to ground- Note the declining trend from the mid 1970s and the nesting birds. Coastal erosion has recovery of the population from 1999 onwards as a caused some loss of the shingle consequence of proactive habitat management.

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Bittern Avocet In the early 1970s, Bert Axell considered Bit- Avocets were discovered breeding in 1947 and, terns to be a threat to the Marsh Harrier’s con- along with others found at to tinued existence as a British breeding bird. the south later in the same year, this marked The two species can be uneasy neighbours and the first confirmed successful breeding in Bert was convinced that Bittern predation of Britain for nearly 100 years. In 1947 four pairs Marsh Harrier eggs was a potentially signifi- of Avocets bred on lagoons in front of where cant threat. Twenty years later that situation the Bittern Hide currently sits. In the absence had reversed: Marsh Harrier populations were of habitat management, vegetation encroached recovering well, but Bitterns were in serious into the Avocet’s nesting habitat and the birds decline. An RSPB research programme was failed to breed in subsequent seasons. Bert instigated to establish the causes of that Axell was not explicit in his intention to decline and understand the Bittern’s habitat encourage Avocets to return to breed on the requirements, with much of the study taking Scrape in the 1960s, but he was certainly suc- place at Minsmere. That research highlighted cessful in doing so. A single pair returned in the impact of reedbeds drying out (a conse- 1963, and numbers increased to 53 pairs by quence of insufficient management) as a 1977 since when they have fluctuated between primary cause of the Bittern’s decline (Gilbert 40 (1991) and 141 pairs (1995; fig. 3). Produc- et al. 2002, 2003, 2005a,b, 2007). With signifi- tivity has declined with increasing numbers cant input from EU LIFE programmes, work and in only two years since 1988 has the to lower the reedbeds and create ditches and number of young fledged per pair exceeded pools was initiated in 1994. This restored the 0.5, despite the anti-predator fence (fig. 3). Bittern from a low point of one booming male Food supply and predation of chicks by Black- to the current population of 9–12 booming headed Gulls Chroicocephalus ridibundus males each year (fig. 2). The research at Mins- appear to have a significant effect on produc- mere was instrumental in habitat creation and tivity in some seasons. The highest number of restoration programmes elsewhere, and has young fledged in a single season was 110 (from been a key part of conservation efforts which 69 pairs) in 1983. have seen the Bittern move from the Red to Amber list of species of conservation concern Stone-curlew in the UK (Eaton et al. 2015). For more infor- The Stone-curlew was lost as a breeding mation on the Bittern’s recovery, see Brown et species in 1969, probably because of a combi- al. (2012) and Wotton et al. (2009). nation of vegetation colonising areas of for- merly bare ground and 150 Avocet 5.0 human disturbance. no. breeding pairs 4.5 The purchase of arable 120 productivity 4.0 land within the reserve 3.5 boundary in 1989 90 3.0 meant that habitat management to 2.5 encourage the return of 60 2.0 breeding Stone-curlews

no. breeding pairs breeding no. 1.5 was feasible. Following 30 1.0 its disappearance from 0.5 Minsmere, this species 0 0 had dwindled to a low 64 68 72 76 80 84 88 92 96 00 04 08 12 16 breeding productivity (fledged young per pair) (fledged young productivity breeding ebb on the Suffolk Fig. 3. Numbers of breeding pairs of Avocets Recurvirostra avosetta at coast, with just a single RSPB Minsmere (red, left-hand axis) with productivity (fledged young pair recorded breeding per pair; blue, right-hand axis), 1963–2016. In the 2015 breeding season, in the mid 1990s. After the number of Black-headed Gulls Chroicocephalus ridibundus was lower (possibly in response to the high rates of nest predation by Badgers trialling had been Meles meles in the previous nesting seasons) and Avocets had their best carried out on a range breeding season for nearly 30 years, when 60 pairs reared 58 young. of different approaches,

442 British Birds 110 • August 2017 • 435–455 Great bird reserves: Minsmere a pair returned to the reserve in 2003. Suc- 12 10 cessful breeding was 9 10 first recorded in 2004 8 and the provision of 7 8 cultivated plots has 6 led to a peak of ten 6 5 breeding pairs (fig. 4). Productivity has been 4 no. fledged young no.

no. breeding pairs breeding no. 4 enhanced by the anti- Stone-curlew 3 predator measures 2 2 no. breeding pairs described above but productivity 1 still fluctuates annually 0 0 in response to a range 03 04 05 06 07 08 09 10 11 12 13 14 15 16 of factors (fig. 4). Fig. 4. Numbers of breeding pairs of Stone-curlews Burhinus oedicnemus (red, left-hand axis) and productivity (fledged young; blue, right-hand axis) Marsh Harrier at RSPB Minsmere, 2003–16. In 1971 the only pair of nesting Marsh Harriers in the UK was at at Minsmere support good populations of Minsmere. From the late 1980s, numbers both species. increased to a peak of 17 nesting females in Dartford Warblers returned to the Mins- 2007 but have subsequently declined to mere heathland in the mid 1990s after an around 8–10 females (fig. 5); since breeding absence of 60 years. The population males at the site are frequently polygynous, increased rapidly until 2005, when numbers the population is monitored by the number started to decline, apparently related to of nesting females. Productivity has fluctu- damage to dwarf-shrub habitat due to ated between 1.0 and 4.5 young per nesting browsing by the expanding Red Deer Cervus female, although in the last decade this has elaphus population, and further com- been more stable, mainly 1.5–2.5 young per pounded by cold winters in the early 2010s. nesting female; lower productivity may have Fortunately, the gorse bushes on the heaths been a factor in the recent decline in appear to have helped the overwinter survival breeding numbers and it will be interesting of at least part of the population and, to see whether the population stabil ises at following a reduction in Red Deer, numbers this level in future years. are now increasing again (fig. 6). European Stonechats Saxicola rubicola declined even Other breeding species more markedly in the 2010s, following a In 1947, as well as the returning Avocets, the Marsh Harrier reserve supported the 18 8 no. nesting females UK’s only known 16 7 breeding Bearded Tits 14 productivity 6 that summer. The sub- 10 5 sequent increase in the 8 4 population and distri- 6 3 bution of the latter no. nesting females no. 4 2 species was studied by 2 1 Bert Axell (see Axell 0 0

1966). Although the 60 64 68 72 76 80 84 88 92 96 00 04 08 12 16 per nest) young (mean no. productivity populations of Bearded Tits, and Water Rails Fig. 5. Numbers of nesting female Marsh Harriers Circus aeruginosus at RSPB Minsmere (red, left-hand axis), with productivity (number of young Rallus aquaticus, fluc- fledged per nest; blue, right-hand axis), 1959–2016. This species was tuate from year to year, recorded breeding from at least 1948, but accurate numbers are not the extensive reedbeds available before 1959.

British Birds 110 • August 2017 • 435–455 443 Rowlands Jon Evans 242. Male Marsh Harrier Circus aeruginosus, Minsmere, April 2009. The only breeding pair in the UK in 1971 was at Minsmere, but this species has subsequently shown a tremendous recovery. Birds can now be seen at Minsmere throughout the year.

series of cold winters; the species 30 briefly disappeared again as 25 a breeding bird, but numbers are now recovering. Watching 20 Stonechats on the heath is once 15 again one of the best ways of locating Dartford Warblers. 10

no. breeding pairs breeding no. Nightjars have declined during 5 the last 15 years, but are now 0 showing some signs of stabilising 96 98 00 02 04 06 08 10 12 14 16 at lower numbers. This is in con- Fig. 6. Numbers of breeding pairs of Dartford Warblers trast to national trends and the Sylvia undata at RSPB Minsmere, 1995–2016. reasons for that are unclear, although again Red Deer may be implicated (through browsing but 35 also disturbance and trampling of 30 nests). Work to reduce the impact 25 of deer, together with clearance of dense stands of Silver Birch to 20 create more open habitats, will 15 benefit Nightjars in the coming 10 years. Since the return of Wood-

no. breeding territories breeding no. 5 larks in 1992, the population has 0 also responded well to the man- 92 94 96 98 00 02 04 06 08 10 12 14 16 agement work described, and Fig. 7. Numbers of Woodlark Lullula arborea breeding although numbers do fluctuate, territories at RSPB Minsmere, since this species returned to they have been increasing since the reserve in 1992. 2011 (fig. 7).

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Table 1. Breeding bird species that have colonised or been lost from RSPB Minsmere, 1947–2017.

colonising species first lost species last year of year of breeding breeding Common Tern Sterna hirundo 1962 Montagu’s Harrier Circus pygargus 1963 Canada Goose Branta canadensis 1963 Corn Bunting Emberiza calandra 1970 Black-headed Gull Chroicocephalus ridibundus 1964 Whinchat Saxicola rubetra 1974 Sandwich Tern Sterna sandvicensis 1965 Red-backed Shrike Lanius collurio 1978 Herring Gull Larus argentatus 1966 Tree Sparrow Passer montanus 1986 Collared Dove Streptopelia decaocto 1972 Northern Wheatear Oenanthe oenanthe 1991 Greylag Goose Anser anser 1976 Common Starling Sturnus vulgaris c. 1992 Lesser Black-backed Gull Larus fuscus 1980 House Sparrow Passer domesticus c. 1992 Cetti’s Warbler Cettia cetti 1980 Woodcock Scolopax rusticola 1993 Tufted Duck Aythya fuligula 1981 Lesser Spotted Woodpecker Hobby Falco subbuteo 1992 Dryobates minor 2001 Dartford Warbler Sylvia undata 1995 Grey Partridge Perdix perdix 2005 Barnacle Goose Branta leucopsis 2005 Little Tern Sternula albifrons 2008 Mediterranean Gull Larus melanocephalus 2005 Spotted Flycatcher Muscicapa striata 2009 Common Buzzard Buteo buteo 2014

Breeding bird species that have colonised and then been lost from RSPB Minsmere, 1947–2017

first bred last bred Common Pochard Aythya ferina 1981 2014 Willow Tit Poecile montana 1967 1990 Lesser Redpoll Acanthis cabaret 1962 1993 David Tipling David 243. Avocet Recurvirostra avosetta, Minsmere, May 2005. Since 1963 the population has fluctuated between 40 and 141 breeding pairs annually and they are easily seen on the Scrape from April to July at least.

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The Sand Martin Riparia riparia colony Work to attract this species back onto the close to the visitor centre has been present Scrape to breed is in progress. Lesser Spotted since at least the 1940s and is maintained in Woodpeckers Dryobates minor last bred on most seasons by scraping the sand face to the reserve in 2001, while numbers of Great provide a suitable nesting site. The breeding Spotted Woodpeckers Dendrocopos major population peaked at 366 pairs in 1987 and have risen significantly. Red-backed Shrikes 320 pairs in 2016. The birds are currently Lanius collurio were a special feature of visits monitored under the BTO’s Retrapping to Minsmere until the 1970s, with pairs regu- Adults for Survival (RAS) survey. Equally larly breeding close to the car park, but nowa- popular are the Barn Swallow Hirundo days the species can be seen only on spring rustica pairs that nest at the main New Cut and autumn passage. Common Snipe Galli- sluice, which must be among the most nago gallinago and Turtle Dove Streptopelia photo graphed Barn Swallows in Britain. turtur have declined rapidly, as have many Maps of the breeding distribution of migrant passerines, including Grasshopper Nightingales on the reserve show that in the Warbler Locustella naevia, Common Redstart 1960s the species was largely found in areas Phoenicurus phoenicurus and Tree Pipit that are now mature woodland (and cur- Anthus trivialis. In the 1960s, Willow Warblers rently lack Nightingales), while historical Phylloscopus trochilus and Common Chiff - photographs indicate that areas now sup- chaffs P. collybita were almost equally porting Nightingales were largely devoid of numerous on the reserve, but by the mid suitable scrub during that earlier period. This 1980s there were ten times as many Willow reflects the national trend for Nightingales Warblers; while Chiffchaffs have recovered, moving from woodland to scrub during the Willow Warblers have declined to just a same period (Holt et al. 2012). handful of pairs in recent years. Savi’s War- Since 1947 there have been many winners blers L. luscinioides are no longer annual, as and losers, reflecting wider population trends they were during the 1970s, but singing males (table 1). Colonists include the Cetti’s have been recorded in several recent years and Warbler Cettia cetti, with a current popula- breeding has been suspected. Yellow Wagtails tion of 125 pairs, while those lost include the Motacilla flava last bred annually in 1985, Little Tern Sternula albifrons, which has not with only occasional single pairs since. Marsh nested since 2008, perhaps as a consequence Tits Poecile palustris remain easily found but of coastal erosion of the , which – again – appear to have declined recently, as has reduced the available nesting habitat. have Meadow Pipits Anthus pratensis. Eric Hosking 244. The creation of the Minsmere Scrape by Bert Axell in the early 1960s represented an innovative form of habitat intervention. The lagoons and islands have provided breeding and feeding areas for waders, terns and gulls, including the iconic Avocet Recurvirostra avosetta.

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Table 2. Rare birds seen at RSPB Minsmere which had occurred fewer than 20 times in Britain since 1950 at the time of the sighting. species date status in Britain, post 1950 Western Swamphen Porphyrio porphyrio July–August 2016 1st (pending acceptance) Baikal Teal Anas formosa November–December 2001 1st (previous British record in 1906; Harrop & McGowan 2009) Siberian Blue Robin Larvivora cyane October 2000 1st (Foster 2006) Trumpeter Finch Bucanetes githagineus May–June 1971 1st (Wallace et al. 1977) Sooty Tern Onychoprion fuscatus June 1966, August 1976 2nd & 5th ‘Thayer’s Gull’ Larus (glaucoides) thayeri March 2016 3rd Slender-billed Gull Chroicocephalus genei August 1971 3rd Lesser Crested Tern Sterna bengalensis August 1992, July 2005 4th & 9th Lesser Yellowlegs Tringa flavipes August 1950 4th Audouin’s Gull Larus audouinii May 2011 6th Stilt Sandpiper Calidris himantopus July 1969, May 1985, 7th, 13th, 19th September 1997 Lesser Kestrel Falco naumanni March 2010 8th Terek Sandpiper Xenus cinereus May 1972, August 1981 8th & 18th Greater Yellowlegs Tringa melanoleuca July–August 1985 10th Cliff Swallow Petrochelidon pyrrhonota November 2016 11th Alpine Accentor Prunella collaris March 2002 15th Isabelline Wheatear Oenanthe isabellina October 1998 15th Baird’s Sandpiper Calidris bairdii August–September 1967 15th Black-winged Pratincole Glareola nordmanni July 1985 16th Little Crake Zapornia parva September 1973 18th Semipalmated Sandpiper Calidris pusilla August 1986 20th Adam Rowlands 245. Current management in front of the hides overlooking the Scrape is carefully designed to provide valuable habitat for key bird species and encourage closer views for visitors; September 2005.

British Birds 110 • August 2017 • 435–455 447 Rowlands Jon Evans 246. Male Bearded Tit Panurus biarmicus, Minsmere, October 2011. Following an exceptionally cold winter, the only breeding pairs in the UK in 1947 were at Minsmere. They have subsequently increased on the reserve. This is a male of a rare variant, which shows a dark brown iris in adult plumage. This polymorphism has been recorded in this species only at Minsmere and nearby Walberswick (Pearson & Greenhalgh 1966) and it appears that the proportion of birds with a dark iris has declined in recent years (D. J. Pearson pers. comm.).

Passage migrants and non-breeding L. michahellis. Peak numbers of the former visitors often occur in the late autumn and early Purchase of the South Levels grazing marshes spring, while the highest numbers of Yellow- has enabled this area to be managed more legged Gulls tend to be found in the late sympathetically for wintering wildfowl and summer. Glaucous L. hyperboreus and Iceland breeding waders. Wintering wildfowl have Gulls L. glaucoides are recorded most years, duly increased, particularly Eurasian Wigeon the latter often in late winter/early spring. Anas penelope, Gadwall A. strepera and Dedicated gull watchers were rewarded with Eurasian Teal A. crecca. Up to 700 Barnacle an adult Audouin’s L. audouinii in May 2011 Geese Branta leucopsis, thought to be mainly and, more recently, an adult ‘Thayer’s Gull’ feral birds (and including some originating L. (glaucoides) thayeri in March 2016 (Brit. from the near Continent), roost on the Birds 109: 335–337). Scrape overnight and – since the fence pre- Seawatching is hard work and rarely pro- venting access by mammalian predators to ductive; in autumn, Sooty Shearwaters the Scrape was erected – a few pairs remain Puffinus griseus, skuas and Little Auks Alle to breed. The flock is regularly swelled by a alle may be seen, and coastal movements of few feral Red-breasted Geese B. ruficollis. Brent Geese B. bernicla, ducks and waders Many gulls loaf on the Scrape, especially can be spectacular. Occasionally, rarer species in the evening, and larger numbers arrive to such as Leach’s Storm-petrel Oceanodroma roost after dark. These are often worth leucorhoa are recorded. searching at any time of year for Caspian Great Grey Shrikes Lanius excubitor are Larus cachinnans and Yellow-legged Gulls recorded on passage in most years, typically

448 British Birds 110 • August 2017 • 435–455 Great bird reserves: Minsmere in late autumn, while Firecrests Regulus igni- and Ortolan Bunting Emberiza hortulana. capilla are regularly seen in late autumn and The variety and totals recorded would surely early spring, with small numbers in some have been higher if Minsmere had had the winters and occasional breeding records. same dawn-to-dusk multiple observer Easterly winds in the early autumn may coverage then as it enjoys today. Nonetheless, encourage drift migrants, with small and late-autumn arrivals of thrushes and finches variable numbers of Pied Flycatchers Ficedula can still be impressive in suitable weather hypoleuca, Common Redstarts and Wrynecks conditions. Small numbers of Penduline Tits Jynx torquilla occurring annually. Declining Remiz pendulinus have been seen in autumn populations of these species in northern and early spring in several recent years, with Europe suggest that a repeat of the amazing the largest party yet to be recorded in Britain fall of 3rd September 1965 is unlikely. In that represented by seven in March 2010 (Brit. fall, an estimated 7,000 Common Redstarts, Birds 104: 595). 4,000 Northern Wheatears Oenanthe oenanthe, 2,000 Garden Warblers Sylvia Rarities borin, 1,500 Pied Flycatchers and 750 Whin- Minsmere is something of a magnet for rare chats Saxicola rubetra predominated among birds and boasts at least two firsts for Britain an astonishing number of migrants displaced (table 2). The recent Western Swamphen Por- across the North Sea after departing from phyrio porphyrio may yet increase that total Scandinavia. Scarcities in that fall also to three, which would make it the third occa- included 25 Wrynecks, 25 Bluethroats Lus- sion that a British ‘first’ was missed by the cinia svecica, two or three each of Dotterel serving manager of the site. Bert Axell Charadrius morinellus, Tawny Pipit Anthus (allegedly) refused to look for the 1971 campestris, Icterine Warbler Hippolais icterina Trumpeter Finch Bucanetes githagineus Adam Rowlands 247. Heathland at Minsmere, in July 2015, showing the mosaic of dwarf shrubs (Heather Calluna vulgaris, Bell Heather Erica cinerea and Western Gorse Ulex gallii) characteristic of the site, with scattered Silver Birch Betula pendula trees and clumps of European Gorse U. europaeus. This is ideal vegetation composition and structure for nesting by Dartford Warblers Sylvia undata, which returned to Minsmere to breed in 1995.

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because he considered it was most likely an the memory of the few who were fortunate to escape. Geoff Welch was unable to connect witness it (just as it will for those of us on site with the Siberian Blue Robin Larvivora cyane at the time who failed to see it). Few would that was seen by a handful of lucky observers have predicted that there would be a Western late one evening in October 2000, following a Swamphen on the same pool just 12 months twitch to see a Sociable Lapwing Vanellus gre- later. Many observers from the 1980s will garius (and a Pallas’s Leaf Warbler Phyllo- remember the excitement caused by the party scopus proregulus) on the reserve. And the of Great Bustards Otis tarda which showed author was on leave in the Netherlands for a short time on the reserve, even though throughout the swamphen’s period of resi- we now know that their occurrence coincided dence on the site. with a reintroduction programme in The area around the sluice bushes has Germany. been a particular magnet for rare birds over European Bee-eaters Merops apiaster the years. The Siberian Blue Robin was dis- occur with increasing regularity and are now covered there and other eastern gems have almost annual; the brief visit by a flock of ten included Red-flanked Bluetails Tarsiger cya- in the summer of 2015 was especially memo- nurus in October 2009 and 2011. The rable. Golden Orioles Oriolus oriolus add a Sociable Lapwing in 2000 was the first in splash of colour most springs, but they Suffolk since 1977, while a Squacco Heron usually do not linger, although the presence Ardeola ralloides in 2007 was the first since of a pair on several occasions has suggested 1912. In July 2015, the adult Black-browed possible breeding attempts. Black Kite Milvus Albatross Thalassarche melanophris that migrans, White-tailed Eagle Haliaeetus albi- landed briefly on a pool on the edge of the cilla, White-winged Black Tern Chlidonias reedbed, which it shared with a small party of leucopterus, Alpine Swift Apus melba, Red- Mute Swans Cygnus olor, will linger long in footed Falcon Falco vespertinus, Red-rumped Eric Hosking 248. European Nightjars Caprimulgus europaeus have nested on the Minsmere heathlands throughout the 70-year history of the RSPB’s involvement in the site. During 1959–2016, the population varied between five and 28 territories each year, with a mean of 16 territories.

450 British Birds 110 • August 2017 • 435–455 Great bird reserves: Minsmere Eric Hosking 249. Nesting Red-backed Shrikes Lanius collurio at Minsmere, year unknown. A familiar sight for visitors to the reserve up until the 1970s, Red-backed Shrikes last bred at Minsmere in 1978. The species remains annual on passage, and drift migrants are recorded in both spring and autumn.

Swallow Cecropis daurica, and Marsh Warbler Natterjack Toads Epidalea calamita, the latter Acrocephalus palustris are further scarce visi- augmented by introduced stock from tors that have been recorded at the reserve on Norfolk in recent years. Some 13 species of several occasions in recent years. fish have been recorded in the ditches and pools, of which Common Rudd Scardinius Other wildlife erythrophthalmus is most numerous and an The reserve supports a rich variety of important prey item for Bitterns. mammals, with over 40 species recorded. A rich variety of invertebrates includes the There are currently approximately 300 Red largest population of Silver-studded Blue Deer and the stags form an impressive sight butterflies on the Suffolk Sandlings. The during the annual rut in October. Otters sandy soils of the reserve provide ideal Lutra lutra and Badgers recolonised Mins- habitat for many ground-dwelling inverte- mere in the late 1980s and numbers of both brates, with a tremendous diversity of bees have increased significantly, with the former and wasps (Hymenoptera) including the Bee now seen regularly in wetland areas during Wolf Philanthus triangulum and the UK’s daylight. The site has retained a healthy pop- only pantaloon bee, the Hairy-legged Mining ulation of Water Voles Arvicola amphibius, Bee Dasypoda hirtipes. The Bee Wolves partly a consequence of efforts to ensure that colonised the reserve in the 1990s, part of a American Mink Neovison vison do not northward range expansion almost certainly become established at the site but also linked to climate change. The same phenom- because their populations are not restricted enon presumably encouraged the arrival of to linear ditch systems, which improves their Ant-lions Euroleon nostras, discovered at resilience to predation. Reptiles and amphib- Minsmere in 1994 and representing the ians include healthy populations of Adders second record for Britain (following the first Vipera berus and a small population of in nearby Westleton in c. 1890). An extension

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to the Visitor Centre in 2012 provided ground on the heathland, and provide a food further breeding habitat for this species and source for Stone-curlews. the sandy margins around the footings of the The shingle ridges on the beach are valu- building must be one of the easiest locations able for their rare coastal floral communities to find the larval pits of Ant-lions in the UK. and other rare plants elsewhere on the site The number of moths and butterflies include the largest concentration of Red- (Lepidoptera) recorded now exceeds 1,100 tipped Cudweed Filago lutescens on the species, including the first and only Mins- Suffolk coast and the only population of mere Crimson Underwing Catocala conjuncta Round-leaved Wintergreen Pyrola rotundi- for Britain (Higgott & Harvey 2005). Several folia in Suffolk. The proliferation of dead other restricted-range moth species have timber in the woodland is of great value to been recorded, including the White-mantled invertebrates and fungi, with over 1,500 Wainscot Archanara neurica, which histori- species of the latter recorded. cally was known only from reedbeds on the Suffolk coast in the UK, but has recently been Visitors discovered in Norfolk. With rising sea levels, Minsmere was originally established as a this species’ continued existence in the UK nature reserve with an emphasis on pro- will depend on its successful dispersal to tecting rare breeding birds, and public access reedbeds away from the threatened coasts of was very limited. Prior to 1980, permits had . A Yellow-legged Tortoiseshell to be obtained to visit and the site has been butterfly Nymphalis xanthomelas at Mins- open to the public seven days a week only mere in 2014 represented part of an invasion since 2005. The current visitor centre opened of this species into the UK (Fox et al. 2015), in 1996 and further improvements to this providing the first British records since one building, with the addition of the Discovery in Kent in 1953. An invertebrate survey of the Centre (a facility with a focus on education Scrape by David Gibbs in 2004 determined it and family engagement), were supported by to be one of the most valuable Diptera habi- the Heritage Lottery and INTERREG tats in Britain, illustrating that dynamic man- (funded by the European Regional Develop- agement techniques focused principally on ment Fund) in 2012. Improvements have also bird populations can provide other signifi- been made to enable access by all visitors cant biodiversity benefits. Impressive to the key habitats on the reserve, with a Minotaur Beetles Typhaeus typhoeus are dedicated programme of activities and events numerous within the acid grassland and bare and the management of habitats to provide Adam Rowlands 250. Extensive grazing using Konik Polski horses has been undertaken at Minsmere since 1999, when the Suffolk Wildlife Trust loaned five horses to the RSPB. The animals share characteristics with the Tarpan Equus ferus, the original wild horse of Europe, and are used to graze the margins of the reedbed to provide valuable transitional habitat, seen here in January 2010.

452 British Birds 110 • August 2017 • 435–455 Great bird reserves: Minsmere opportunities for close viewing of wildlife. improved the protection of the Scrape and There has also been an effort to enable the main reedbed while allowing future improved viewing and interpretation of a coastal realignment in the North Marsh in number of iconic species on the site, due course. This should enable the main including a Stone-curlew viewpoint close to freshwater habitats to be maintained in situ the visitor centre; locations to see scarce for the next 50 years while plans for further insects such as Ant-lions and Bee Wolves; future adaptation are developed. Increased trails in spring offering opportunities to nitrogen deposition from the atmosphere watch basking Adders; and seasonal trails could threaten the dwarf-shrub communities with access to wader pools, the reedbed and and favour an increase in grass cover. All of areas of scrub during autumn migration. Vol- the potential impacts of climate change need unteer guides are present on site on a daily to be considered when planning the future basis to assist visitors in finding wildlife and management of the site. also lead the popular Red Deer rut safaris. The proposed development of a new Bird ringing demonstrations, currently led by nuclear reactor at Sizewell, to the south of the the Waveney Bird Club and supported by the reserve, will need to be monitored closely to BTO, are also extremely popular with visitors of all ages and are the second- largest public engagement ringing events nationally after the Birdfair. The popularity of the site grew in the 1980s when Minsmere hosted the BBC live Birdwatch programmes with Tony Soper in 1981 and 1989. Some 25 years later there was another spike in public interest with the BBC Springwatch pro- grammes, broadcast live from the site between late May and mid June in 2014–16. These programmes provided a great insight into the wildlife on the reserve, revealing fascinating behaviour for both the public and the staff on the reserve. High-quality engagement with visitors is essential to furthering support for conservation and inspiring a younger generation who are increas- ingly disconnected from nature; Mins- mere plays a key role in delivering this aim for the RSPB.

The future Challenges for Minsmere include climate change, with sea-level rise lim- iting our ability to drain the marshes and causing a greater incidence of river flooding. Coastal erosion is also likely to have an increasing impact and decisions will have to be made about the sustain- ability of the freshwater habitats in the Adam Rowlands medium to long term. The Environ- 251. Over 100 water control structures are deployed for the hydrological management of the Minsmere ment Agency undertook a project to wetlands. Here, Robin Harvey and Annette Salkeld can realign the sea defences at the northern be seen operating one of the sluices that controls end of the wetland in 2012, which has water levels on the Scrape in January 2017.

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breeding birds in Britain. It has also contributed significantly to the conser vation for- tunes of the Stone- curlew on a more local scale. It has played a pivotal role in inspiring a gen- eration of natural historians and con- tinues to foster an interest in wildlife and the countryside among the thou- sands of visitors

Sue Alderman Sue who enjoy the 252. Many older visitors to Minsmere today recall that the first ‘spark’ that reserve today. There inspired them in their lifelong interest in birds was being shown a ringed bird in the hand by Bert Axell. We are proud to maintain that tradition is every reason to today with the ringing demonstrations organised by the Waveney Bird Club hope that this fan- in close collaboration with the BTO. Here, Carl Powell allows a young visitor tastic place for to release a Goldcrest Regulus regulus in September 2012. people and wildlife will continue to ensure that there are no adverse effects on the thrive in the coming years. reserve during construction and operation. The impacts of the decision for Britain to Acknowledgments leave the EU remain to be established, but I am extremely grateful to Malcolm Ausden and Robin Harvey, who provided comments that improved this continued legal protection for the designated article considerably; to the photographers whose habitat on the site and access to suitable images have enhanced the layout; to Simon Barnes funding for major land management works and John Grant for their continued enthusiasm for will be important to the future success of the celebrating all that is magical about the reserve; and to the many colleagues at RSPB and partner organisations site. and regular visitors who make working at Minsmere Future potential colonists include such a pleasure. Common Crane Grus grus (with specific management activity in the wetlands aimed References at creating suitable habitat) and Great White Ausden, M., & Kemp, M. 2005. Creating heathland by adding sulphur, and heather Calluna and bell Egret Ardea alba. Hopes have been raised by heather Erica cuttings, at Minsmere RSPB Reserve, displaying Purple Herons A. purpurea on Suffolk, England. Conservation Evidence 2: 24–25. several occasions, particularly in 2007 when a www.conservationevidence.com/reference/ download/2142 pair and an additional male were behaving as —, Allison, M., Bradley, P., Coates, M., Kemp, M., & though a breeding attempt was under way. Phillips, N. 2010. Increasing the resilience of our Heavy rain unfortunately led to the birds’ lowland dry heaths and acid grasslands. Brit. Wildlife departure, despite attempts to control water 22: 101–109. Axell, H. E. 1966. Eruptions of Bearded Tits during levels, and subsequent searches failed to 1959–65. Brit. Birds 59: 513–543. locate a nest. It remains to be seen which — 1977. Minsmere: portrait of a bird reserve. species will successfully colonise the site in Hutchinson, London. the future and which will be lost. Barnes, S. 1992. Flying in the Face of Nature: a year in Minsmere bird reserve. Pelham Books, London. Minsmere celebrated its 70th anniversary Berry, R. 1979. Nightjar habitats and breeding in East as an RSPB Reserve on 25th April 2017. Anglia. Brit. Birds 72: 207–218. During this period it has played an instru- — & Bibby, C. J. 1981. A breeding study of Nightjars. Brit. Birds 74: 161–169. mental role in the survival of the Avocet, Brown, A., Gilbert, G., & Wotton, S. 2012. Bitterns and Bearded Tit, Bittern and Marsh Harrier as Bittern conservation in the UK. Brit. Birds 105: 58–87.

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Burgess, N. D., Evans, C. E., & Sorensen, J. 1990. success of the Great Bittern Botaurus stellaris in The management of lowland heath for Nightjars at Britain. Ibis 149: 53–66. Minsmere, Suffolk, Great Britain. J. Env. Management Harrop, A. H. J., & McGowan, R. Y. 2009. Britain’s first 32: 351–359. Baikal Teal. Brit. Birds 102: 691–696. Eaton, M., Aebischer, N., Brown, A., Hearn, R., Lock, L., Higgott, J. B., & Harvey, R. M. 2005. Catocala conjuncta Musgrove, A., Noble, D., Stroud, D., & Gregory, R. (Esper, 1787) (Lepidoptera: Noctuidae) new to the 2015. Birds of Conservation Concern 4: the British Isles. Entomologist’s Gazette 56: 217–222. population status of birds in the UK, Holt, C. A., Hewson, C. M., & Fuller, R. J. 2012. Islands and Isle of Man. Brit. Birds 108: 708–746. The Nightingale in Britain: status, ecology and Foster, K. 2006. Siberian Blue Robin at Minsmere: new conservation needs. Brit. Birds 105: 172–187. to Britain. Brit. Birds 99: 517–520. Liddiard, R., & Sims, D. 2013. A Hedgehog on the Fox, R., Parker, R., Pettersson, L., van Sway, C., & Stone, heath. The Second World War landscape of B. 2015. Mass immigration and overwintering of Exercise ‘Kruschen’, Dunwich, Suffolk. Scarce Tortoiseshell Nymphalis xanthomelas (Esper, The Archaeological Journal 169: 519–549. 1971) in 2014/15. Atropos 54: 3–14. Pearson, D. J., & Greenhalgh, M. E. 1966. Observations Gilbert, G., Tyler, G. A., & Smith, K. W. 2002. Local on the iris colour of Bearded Tits. Bird Study annual survival of booming male Great Bittern 13: 328–331. Botaurus stellaris in Britain, in the period 1990– Rowlands, A., Harvey, R., & Rayner, A. 2015. RSPB 1999. Ibis 144: 51–61. Minsmere & Dingle Marshes management plan, —, — & — 2003. Nestling diet and fish preference of April 2015–March 2020. RSPB, Sandy. Bitterns Botaurus stellaris in Britain. Ardea 91: 35–44. Wallace, D. I. M., Cobb, F. K., & Tubbs, C. R. 1977. —, — & — 2005a. Behaviour, home range size and Trumpeter Finches: new to Britain and Ireland. habitat use by male Great Bittern Botaurus stellaris Brit. Birds 70: 45–49. in Britain. Ibis 147: 533–543. White, G. 2009. The future of reedbed management. —, —, Dunn, C. J., & Smith, K. W. 2005b. Nesting RSPB Information and Advice note, Sandy. habitat selection by Bitterns in Britain and the Wotton, S., Brown, A., Burn, A., Dodd, A., Droy, N., implications for wetland management. Biol. Conserv. Gilbert, G., Hardiman, N., Rees, S., White, G., & 124: 547–553. Gregory, R. 2009. Boom or bust – a sustainable —, —, —, Ratcliffe, N., & Smith, K. W. 2007. The future for reedbeds and Bitterns? Brit. Wildlife influence of habitat management on the breeding 20: 305–315.

Adam Rowlands, East Walks Bungalow, Minsmere RSPB Reserve, Westleton, Suffolk IP17 3BY; e-mail [email protected]

Adam Rowlands began his RSPB career as a seasonal Assistant Warden at Minsmere in 1988. Following various posts on reserves around the country, he returned to Minsmere to take up the position of Senior Site Manager in 2004, a post he still holds today. His interest in rare birds led to a stint on BBRC from 1999 and he was Chairman from 2007 to 2015. Jon Evans 253. Great White Egret Ardea alba and Sizewell B power station, March 2017. This species is increasingly seen throughout the year and is a potential future colonist.

British Birds 110 • August 2017 • 435–455 455 Vulgar errors – the point of a guillemot’s egg: why the widely believed explanation for the guillemot’s pointed egg is almost certainly wrong Tim Birkhead

Abstract The egg of the Common Guillemot Uria aalge is strikingly beautiful. Although colour and patterning are variable, it is typically a vivid blue. Equally striking is its pyriform shape, and the biological significance of this has long been misinterpreted. Traditionally it has been thought that the pyriform shape of both Common and Brünnich’s Guillemot U. lomvia eggs is related mainly to the prevention of the egg from rolling off the often precarious breeding ledges. Here, I bring the story up to date, with current research into, and explanations for, the shape of a guillemot’s egg.

Introduction The history of ornithology is riddled with what we might call ‘vulgar errors’. For example, in the six- teenth and seven- teenth centuries it was thought that a dead Common King- fisher Alcedo atthis suspended from a silken thread could predict – from the direction its bill pointed – which way the wind was going to blow. From the Middle Ages until the early 1800s it was believed that Barn Swallows Hirundo rustica overwintered in the mud at the bottom of ponds. Tim Birkhead 254. The pyriform egg of a Common Guillemot Uria aalge at the site where And in the eighteenth it was laid, on a cliff ledge on Skomer Island, Pembrokeshire, in May 2016. and nineteenth cen-

456 © British Birds 110 • August 2017 • 456–467 Vulgar errors – the point of a guillemot’s egg turies it was thought that the Common remarkably persistent, debunked only in the Cuckoo Cuculus canorus deposited its egg face of convincing new evidence. Even then, into a host’s nest by laying the egg on the some people continue to remain sceptical ground, picking it up in its bill and then about ‘facts’ that are supported by a huge placing it in the nest. amount of scientific evidence, believing, for The ability of a dead Kingfisher to predict example, that the earth is not round; that the weather was mere folklore, as was ably there is no climate change; that vaccines demonstrated by Sir Thomas Browne in the cause autism; or that natural selection is not mid 1600s by a simple experiment that the main driving force of adaptation. involved suspending two Kingfishers side by Another probably erroneous ornithological side and showing that they invariably pointed belief that has had a long life concerns the their bills in different directions. Browne was pyriform shape of a guillemot’s egg (plate part of the seventeenth-century scientific 254). revolution and saw it as his mission to dispel what he called ‘vulgar errors’. At that time Guillemot eggs: early ideas and ‘vulgar’ simply meant ‘common’, so these conclusions were common mistakes (Birkhead 2008). Both the Common Guillemot Uria aalge and The Swallows-in-mud story had some Brünnich’s Guillemot U. lomvia produce a basis in fact. Swallows disappear in autumn single pyriform (= pear-shaped), or pointed and reappear in spring and they were occa- egg at each breeding attempt (fig. 1) and if sionally found dead under water (presumably you ask almost anyone why this is so, their after dying while roosting in reedbeds). It answer is usually that a pyriform shape took a number of experiments (in the eigh- allows the egg to either ‘spin like a top’ or ‘roll teenth and nineteenth centuries) to show in an arc’ to prevent it from tumbling to its that Swallows were unable to breathe under doom. water. The confirmation of migration came The spinning-like-a-top (albeit on its side) eventually from recoveries of ringed birds idea was first suggested by the oologist (Birkhead 2008). William Hewitson (1831): ‘their larger end The Cuckoo belief was reaffirmed in moving around the smaller in a circle, keeps peoples’ minds by seeing Cuckoos with an them in their original position’. Francis egg in their bill, or by finding an egg in the Orpen Morris, in his extremely popular A throat of a shot bird, but not realising that History of British Birds (Morris 1856, com- these were host eggs, not those of the monly referred to as ‘Morris’s Birds’), Cuckoo. The fact that Cuckoo eggs were repeated Hewitson’s suggestion, when he sometimes found in nests, like those of the wrote that: ‘the shape of the [guillemot] egg, Wren Troglodytes troglodytes, with a tiny entrance into which a Cuckoo simply couldn’t fit, was also consistent with the belief that the Cuckoo deposited its egg using its bill. The truth – that Cuckoos deposit their eggs via their cloaca as in other birds – was revealed by the detailed field observations and cinemato- graphic evidence of Edgar Chance during the first two decades of the twentieth century (Schulze-Hagen et al. Fig. 1. Egg silhouettes of Common Guillemot Uria aalge, 2009). Brünnich’s Guillemot U. lomvia and Razorbill Alca torda, to In general, old ideas and illustrate the range of shapes (all to the same scale, from theories such as these are often Birkhead & Thompson unpublished).

British Birds 110 • August 2017 • 456–467 457 Birkhead

proceeded, they tested this idea in a rather crude manner. Belopol’skii arranged for Uspenski to fire a gun beside a group of incubating guillemots soon after laying had started and they subse- quently examined the embryos in the many eggs that rolled off the ledge. Uspenski then went back Fig. 2. The shift in the centre of gravity and position on the substrate of a guillemot egg during the course of incubation, as to the same ledge when the illustrated by Belopol’skii (1961). A at the beginning of incubation; remaining eggs were close B at the end of incubation; n = air space; m = egg content; a = angle to hatching and fired formed at the beginning of incubation; b = angle formed at the end another shot: ‘An enor- of incubation; 1 = position of centre of gravity; 2 = former position mous swarm of birds rose of centre of gravity. in the air, but not a single which is very tapering, prevents it from egg tumbled over the ledge,’ he reported. rolling into the sea; for when moved by the Remarkable! To Belopol’skii this was con- wind, or other circumstances, it only rolls vincing evidence that well-incubated round in its own circle, without changing its guillemot eggs were more stable. He did not first immediate situation.’ I suspect that seem to have considered the fact that all the Hewitson based his idea on a blown egg – an vulnerable eggs were lost as a result of the empty eggshell – from his collection, rather first shot, and what was left were those eggs than an intact egg. If you take an empty (and in safe sites. hence very light) guillemot eggshell, it is Nonetheless, guillemot eggs do become indeed possible to spin it like a top. However, more stable during the course of incubation, real guillemot eggs – full of yolk, albumen or as Belopol’skii discovered. The angle at which an embryo – do not spin on their axes when a guillemot egg rests on the cliff ledge knocked. The spinning-like-a-top idea was changes through incubation as its centre of firmly dismissed as nonsense by Wade gravity shifts towards the pointed end of the (1903), a careful observer with much direct egg (fig. 2). This happens as a result of the air experience of guillemots and their eggs in the cell increasing in size as the embryo develops. field. The Russian seabird biologists of the Uspenski (1958) then reported that this 1930s and 1940s also discounted the idea, change in the resting angle of the egg resulted although perhaps because much of their in a well-incubated egg rolling in a smaller research was written in Russian and not arc than a fresh egg. This is true: if you take widely available, the spinning-like-a-top idea both a fresh and a well-incubated guillemot still persists today (Kaftanovski 1951; Birk- egg and allow them to roll on a smooth, head 2016). gently sloping surface, the arc described by It was the Russian biologists studying the fresh egg is larger, on average. I did such a Common and Brünnich’s Guillemots in Mur- test in the 1970s when I was doing my PhD mansk and Novaya Zemlya in the 1940s– on Common Guillemots and it confirmed 1960s, with a view to harvesting both eggs Belopol’skii’s and Uspenski’s observations and adults for human consumption, that (see also Ingold 1980). started the rolling-in-an-arc idea. Uspenski Belopol’skii’s extensive and impressive (1958) and his colleague Belopol’skii (1961) studies of seabird biology – including the noticed that the majority of guillemot eggs guillemot egg ideas – were first published in that fell off the breeding ledges contained Russian in 1957, and then translated into tiny embryos and had clearly been incubated English as Ecology of Sea Colony Birds of the for only a few days. Speculating that the Barents Sea in 1961. Together with the work guillemot egg gained stability as incubation of his colleague Uspenski (1958), this appears

458 British Birds 110 • August 2017 • 456–467 Vulgar errors – the point of a guillemot’s egg to be the origin of the idea that the pyriform pointed the egg, the less likely it was to be shape of guillemot eggs allowed them to roll lost. This was a result that reaffirmed the in an arc and hence minimise the chances of value of a pointed egg for the Common falling off a ledge. Guillemot, and it was subsequently cited by It is not clear that either Belopol’skii or other researchers (e.g. Drent 1975) and in Uspenski performed many (or any) experi- major ornithology textbooks (e.g. Gill 2007). ments with the eggs; they certainly do not Later, however, Tschanz and his colleagues provide any data on egg-rolling. As far as realised that plaster eggs do not behave in the they were concerned, they had solved the same way as real eggs. One of Tschanz’s stu- problem of why guillemot eggs are the shape dents, Paul Ingold, undertook a PhD devoted they are. The pyriform shape allows the egg to rolling real Common Guillemot and to roll in an arc, while the shift in the centre Razorbill eggs on real ledges, to further test of gravity was probably an adaptation the value of egg shape. The results from these because the closer the egg gets to hatching careful and extensive experiments were very the more valuable it becomes to the parents. different. Ingold could find no real benefit of It sounds entirely reasonable and is intu- a pointed egg in terms of avoiding rolling off itively appealing, especially the idea that as a ledge. The Common Guillemot’s pyriform the embryo approaches hatching the ‘clever’ egg may well roll in an arc on a smooth, shift in the egg’s centre of gravity makes the sloping surface in the laboratory, but few developing chick safer. However, we now guillemot breeding ledges are like that. know that the eggs of all bird species exhibit Ingold’s findings suggested that the results the same shift in the centre of gravity, so this from those earlier trials by Tschanz et al. is unlikely to be a guillemot-specific adapta- (1969) were biologically unrealistic. tion, and indeed is simply a by-product of During his experiments, Ingold found the way the embryo develops (Romanoff & that, in addition to its shape, the mass of an Romanoff 1949). egg also affected the way it rolled. Heavier To be fair, we shouldn’t judge either (that is, larger) eggs rolled in a wider arc than Belopol’skii or Uspenski by today’s scientific lighter eggs. Many of Ingold’s experiments standards. What was considered ‘evidence’ involved comparisons of the rolling trajec - then is very different from what would be tories of the pyriform egg of the Common considered robust and acceptable evidence Guillemot and the elliptical-ovate egg of the today. Razorbill. Not only did the eggs of the two In the 1950s, a school teacher from species differ in shape, those of the Razorbill Switzerland, Beat Tschanz, started a PhD on were generally smaller and therefore lighter cliff-breeding adaptations of Common in mass. On the basis of a small number of Guillemots breeding in the Lofoten Islands, tests, Ingold suggested that if Common Norway. Intrigued by the Russians’ earlier Guillemot eggs were the same shape as findings regarding guillemot egg shape and Razorbill eggs, their greater weight would rolling, Tschanz decided to test their ideas. render them more vulnerable to rolling. In He recognised that guillemot eggs vary quite other words, even though he found no differ- considerably in shape, with some being more ence in the likelihood of rolling off a ledge elongate and pointed than others (fig. 1). between the two species overall, the effect of Using plaster of Paris, he made model eggs of weight was a lifeline to the rolling-in-an-arc these different shapes, and also of the much hypothesis, and the idea that a pyriform less pointed eggs of the Razorbill Alca torda shape might reduce the chances of rolling – the latter’s eggs are usually referred to as might still be true. ‘elliptical-ovate’ in shape (see fig. 1). He and Ingold (1980) also suggested that this egg- two colleagues then tried pushing these dif- mass effect might explain an anomaly: that ferent model eggs to see if they rolled off the the eggs of Brünnich’s Guillemot are less ledge. pointed that those of the Common The results (reported in Tschanz et al. Guillemot even though the former invariably 1969 – in German but with an English breeds on narrower cliff ledges and summary) seemed to be clear-cut: the more its eggs are therefore more vulnerable

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255–257. Habitat differences between Brünnich’s Uria lomvia and Common Guillemots U. aalge. Brünnich’s always breed on narrow ledges while Common Guillemots breed on both narrow ledges and flat areas. Robert Barrett 255. Brünnich’s Guillemots on Hornøya, Finnmark, Norway, June 2014. Tim Birkhead 256. Common Guillemots at Bempton Cliffs, Yorkshire, June 2016. Roy W. Lowe/United States Fish & Wildlife Wildlife Service Lowe/United States Fish & W. Roy 257. Common Guillemot colony on Yaquina Head, Oregon Islands National Wildlife Refuge, Oregon, USA, April 2009.

460 British Birds 110 • August 2017 • 456–467 Vulgar errors – the point of a guillemot’s egg to rolling (plates 255–257). Ingold’s explanation was that because Brünnich’s Guillemot eggs are smaller and there- fore lighter than Common Guillemot eggs, they would roll in a narrower arc and could afford to be less pointed. Published in German with only a brief English summary, Ingold (1980) concluded that: ‘Laboratory and field experi- Fig. 3. Relationship between an index of egg volume (l x b2, where l is the ments with several length of the egg and b is its breadth at the widest point) and adult body hundred eggs mass (means) for different geographic populations of Brünnich’s Uria lomvia showed that the (open circles) and Common Guillemots U. aalge (redrawn from Harris & Birkhead 1985, which includes the identity of populations). pear-shape evidently protects an egg that is rolling away from the published in German, I read only the English nesting site from falling off. Though summaries of Tschanz’s and Ingold’s papers. Guillemot eggs do not stay on the ledges Then, in 2012, I saw the erroneous spinning- better than Razorbill eggs, they would – like-a-top explanation for guillemot egg due to their higher weight – be in greater shape given prominent coverage in a wildlife danger of falling off if they had the shape television programme and decided to take a typical of a Razorbill egg.’ closer look at the adaptive significance of egg This research brings us up to 1980 with shape in guillemots and other birds. the rolling-in-an-arc story more or less still The first step was to have Ingold’s 1980 intact. paper translated into English. Realising that the evidence for the rolling-in-an-arc Current research on guillemot hypothesis was so limited, my colleagues eggs John Biggins, Jamie Thompson and I decided I have studied guillemots (of both species) in various locations including Skomer Island, in Pembrokeshire, and in Labrador and the Canadian High Arctic since 1972. I had never been entirely convinced by the egg-rolling idea, but until recently had not conducted much research on it. And Fig. 4. An index of egg shape (pointedness = b/(a + b)) with examples of since they were Common Guillemot Uria aalge eggs showing different pointedness values.

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that the next step was to test Ingold’s expla- Nettleship 1984; Birkhead et al. 2017a). nation for why Brünnich’s Guillemot eggs are Measuring pointedness is more challenging less pointed than those of Common Guille- because there is no single index that captures mots. We knew from previous work that egg shape. Over the years, researchers have adult Brünnich’s Guillemots are generally devised several different indices of egg shape, slightly smaller (and hence lighter) than some complex, some relatively simple. We Common Guillemots and as a result lay opted for a simple index: the proportion of slightly smaller eggs, on average. But we also overall egg length between the egg’s knew that because of geographical variation maximum breadth and its more pointed end. in body size, the largest Brünnich’s Guille- Fig. 4 provides some examples. mots are larger than the smallest Common If Ingold’s hypothesis was correct, we pre- Guillemots; and consequently there are some dicted that: (i) pointedness should be greater populations of Brünnich’s Guillemot that in larger eggs of both species and, crucially, produce larger eggs than those of some (ii) it should be similar in eggs of similar size Common Guillemots (fig. 3). What was the in the two species. shape of the eggs in these different popula- What we found was a very slight increase tions like? If Ingold was correct, the largest in pointedness with egg size in both species, Brünnich’s Guillemot eggs should be more and that the eggs of Brünnich’s Guillemots pointed than those of the smallest, and thus were on average less pointed than Common more similar in shape to Common Guillemot Guillemot eggs, regardless of their size. In eggs. other words, there was very little support for We assumed that guillemot eggs would be Ingold’s idea. I should point out that the sta- abundant in museum collections and that it tistically significant relationship between egg should be relatively simple to obtain suffi- volume and pointedness was very weak, with cient data to test Ingold’s idea. In fact, very egg volume accounting for less than 3% of few museums had sufficiently large samples the variation in egg shape. This is because for of eggs from specific colonies. Instead, we eggs of a given size there is considerable vari- measured as many eggs of the two species as ation in egg shape, in both species (Birkhead we could, and rather than comparing the egg et al. 2017a; see fig. 1). shape between populations of both species, we pooled those data from all our samples. Other hypotheses for the shape of That wasn’t quite as elegant as we had hoped, a guillemot’s egg but still provided a robust test. If rolling in an arc is not the main selective Measuring egg volume (which is very force shaping guillemot eggs, what is? Ingold closely related to mass) was straightforward (1980) acknowledged that there may be selec- using a tried and tested equation (Birkhead & tion pressures other than rolling that affect Tim Birkhead 258. Common Guillemots Uria aalge on Skomer Island, Pembrokeshire, May 2017; many of the birds are incubating.

462 British Birds 110 • August 2017 • 456–467 Vulgar errors – the point of a guillemot’s egg Jamie Thompson Jamie 259. Intact eggs of Common Guillemot Uria aalge (left) and Razorbill Alca torda (right), showing in two dimensions the difference in the proportion of eggshell in contact with the substrate. the shape of guillemot eggs, including density, in close bodily contact with con- ‘weather conditions, predators and con- specifics, an adaptation that minimises egg specifics’, although he did not elaborate or and chick predation by predatory gulls and test any other hypotheses. He also acknowl- corvids. Brünnich’s Guillemots usually breed edged the idea proposed by Johnson (1941) on narrow ledges, in a linear arrangement; that the Common Guillemot’s pyriform egg Common Guillemots may do the same, but may be an adaptation to facilitate more effi- sometimes also breed on broad ledges and cient incubation, given the semi-upright flat expanses of rock where they achieve posture adopted by the adult bird during much higher densities (on average around 20 incubation (plate 258). pairs per m2 but up to an extraordinary 70 There are a few other hypotheses, pairs per m2; plate 257). Both species lay and although none that I can find in print. If you incubate their egg on the bare rock of the talk to people about guillemot egg shape and cliff ledge. During incubation the egg is ask them for ideas (other than rolling), the usually positioned between the legs, but not commonest response is that a pointed egg on them. As a consequence of the high may be easier to lay than a ‘conventionally’ breeding density, the egg rests on a hard sub- shaped egg, especially given that a guillemot strate and in the general bustle of the colony egg is relatively large (around 12% of adult (fights are frequent) eggs are vulnerable to mass). I think this is unlikely, given that other physical damage from conspecifics – and birds, notably Procellariiformes, lay much especially from incoming individuals that larger eggs relative to body size (up to 25% of land on incubating birds. The pyriform egg adult mass in some petrels), and their eggs shape may confer some protection from such are not at all pyriform. impacts. Another idea is that a pointed egg may As anyone who has ringed guillemot increase the adults’ ability to ‘handle’ the egg. chicks (of either species) will know, their When Tschanz et al. (1969) substituted the breeding colonies can be very dirty places, eggs of Common Guillemots for spherical especially in wet weather. High-density model eggs, they found that most birds lost breeding prevents birds from directing their them. We found the same in our experi- faeces away from conspecifics so breeding ments. This hardly constitutes a test, but it is ledges are notoriously filthy. Consequently, suggestive. guillemot eggs are vulnerable to becoming One way of generating other hypotheses is contaminated by guano. Such contamination to consider those features of the two species’ could block the pores in the eggshell and/or breeding biologies that are unusual. For facilitate microbial infection through the example, compared with the eggs of most pores, both of which could compromise other birds, those of both guillemot species are embryo development. One consequence of a vulnerable to: (i) impacts and breaking, and pyriform egg is that the region below the (ii) contamination of their surface with dirt. widest point lies in contact with the substrate Both species typically breed at high and is vulnerable to contamination, whereas

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the blunt pole of the egg is much less likely to strength, in part through the considerable be contaminated in this way. My colleagues thickness of the shell along that portion of John Biggins, Duncan Jackson, Jamie the egg in contact with the substrate and Thompson and I wondered whether the pyri- where an impact is most likely (Birkhead et form egg might also be an adaptation to al. 2017b). resting on dirty ledges, as a way of min- In addition, however, this allows the blunt imising contamination, especially at the pole of the egg – which is where the chick blunt end of the egg, which is where the emerges – to be thinner, thereby facilitating chick emerges at hatching. We examined each hatching. In other words, a pyriform egg hypothesis in the Common Guillemot. with a thick shell along its more pointed A pyriform egg has a greater proportion portion provides protection from impacts, of its shell in contact with the substrate than but at the blunt pole is still thin enough to does an elliptical-ovate egg like that of the permit efficient hatching (Birkhead et al. Razorbill. This is evident if you look at incu- 2017b). bated eggs of the two species in profile (plate As far as the avoidance of dirt is con- 259). cerned, we examined incubated eggs and Having a larger area in contact with the found that most faecal contamination substrate may be important because it means occurred at the pointed end of the egg, that the physical effects of any impact are although in some cases the contamination likely to be spread over a greater area of occurred all over the egg. We compared the shell, and reduce the likelihood of breakage. contamination of Common Guillemot eggs This is a difficult idea to test directly, in part with that of Razorbill eggs laid on the same because it would require destroying intact broad ledge, and found that no Razorbill eggs eggs, but also because it would require simu- were contaminated to the same extent as lating the type of impacts guillemot eggs are Guillemot eggs, and what little contamina- subjected to. We speculated recently that the tion Razorbill eggs had was distributed across pyriform shape of the guillemot egg provides the eggshell (plate 260). Jamie Thompson Jamie 260. Top two rows = Razorbill Alca torda eggs; bottom two rows = Common Guillemot Uria aalge eggs, taken from the same broad ledge on Skomer in 2016 after approximately 22–25 days’ incubation. (Eggs scaled to same length.) Note the differences between species in the amount and distribution of (mainly) faecal contamination (from Birkhead et al. 2017b).

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The end of ‘rolling in an arc’ as an Complex explanations in the explanation for the pyriform egg? current scientific climate The idea that a pyriform shape is an adapta- People, including biologists, love single- tion that allows the guillemot egg to roll in an factor explanations. The idea that the pyri- arc to prevent it from falling off the ledge is form shape of a guillemot’s egg ensures that no longer very convincing. The idea gained it rolls in an arc and saves it from falling has traction because it was assumed that egg loss intuitive appeal. The idea is attractive via rolling – as per the Russian and other because it reinforces our ‘isn’t nature won- studies (see also Tuck 1961) – is substantial. derful’ view or, alternatively, that natural However, detailed observational studies of selection has solved a particular problem in a guillemot breeding success show that undis- ‘clever’ way. Simply because something is turbed guillemots almost never leave their intuitively appealing does not necessarily egg unattended (one parent is always mean it is true. The idea that guillemot egg present), and that egg loss is much lower shape might have evolved for different, less than recorded in some of the early studies obvious, reasons is harder to grasp. (Tschanz et al. 1969; Birkhead & Nettleship Once established, intuitively appealing 1980). This is not to say that egg loss through single-factor explanations can be difficult rolling never occurs; it does, but it is much to displace, even with good evidence. In the less common than suggested by previous 1800s, it seemed intuitively obvious that studies. Only when faced with large preda- the only way a Cuckoo could get its egg tors, such as foxes, bears or humans, or in into a Wren’s nest was by placing it there response to a catastrophic event such as a with its bill. Only when Edgar Chance pro- gunshot at close range or a rockfall, do guille- vided incontrovertible film footage of mots abandon their egg in a panic. Cuckoos laying did the correct view start to There are several other reasons for prevail. doubting the idea that a pyriform egg shape is The explanation for why guillemots an adaptation to minimise losses via rolling: produce a pyriform egg may be far from (i) Guillemots often breed on ledges much straightforward. Most evolutionary adapta- narrower than the arc described by a tions are a compromise between different rolling egg (Harris & Birkhead 1985; selection pressures. It would, for example, be Birkhead & Nettleship 1987; plates possible for a guillemot to produce a conven- 255–257). In addition, as pointed out tionally shaped egg with a shell strong earlier, Brünnich’s Guillemots produce enough to withstand any number of impacts, less pyriform-shaped eggs than Common but such an egg would make hatching diffi- Guillemots (Belopol’skii 1961; Harris & cult and dangerous for the chick. Natural Birkhead 1985; fig. 1), despite breeding selection results in the evolution of the best on narrower ledges (Birkhead & Nettle- compromise. Identifying the selection pres- ship 1987). sures that guillemot eggs are subject to is the (ii) Since guillemots typically incubate best way of understanding why their eggs are facing the cliff wall, with the pointed end the shape they are. of their egg directed towards the cliff The public has always favoured scientists edge (Tschanz 1969; pers. obs.), a dis- who make strong claims and tell simple lodged egg would roll outwards towards stories, but never more so than in the the cliff edge and thus be more (rather current, highly competitive, cash-strapped than less) likely to fall. research environment. Sadly, some scientific (iii) Guillemot eggs vary considerably in journals encourage authors to oversell their shape (Tschanz et al. 1969; fig. 1), sug- results in this way. Yet the reality is that if gesting that there is little stabilising selec- something seems too good to be true, it tion on egg shape. Thus if egg shape were probably is. Even when all the available data particularly important in these birds, in support a particular hypothesis, experience terms of rolling, there would be little tells us that what we are dealing with in variation in the shape of eggs of the same science is ‘truth for now’. In other words, mass, which is not what we observed. given the available evidence, this is currently

British Birds 110 • August 2017 • 456–467 465 Birkhead what we believe to be correct, but it is pos- that a pyriform shape reduced the chances sible that in the future, with new data or of a guillemot egg rolling off a ledge. technology, we might see things differently. However, on the basis of his observations Similarly, a scientist can tackle a particular and experiments, Ingold (1980) suggested a problem and make some progress, but not modified mechanism by which the rolling- fully resolve a problem. Under these circum- in-an-arc hypothesis might operate: that egg stances what usually happens is either that shape and weight together determine an the study is abandoned or that the story is egg’s rolling trajectory. A prediction from written up in such a way that the results this is that large (i.e. heavier) Brünnich’s seem much more clear-cut than they really Guillemot eggs should be more pointed are. What rarely happens is that the than smaller ones, and that the eggs of researcher states ‘we have made some Brünnich’s Guillemots and Common Guille- progress… and more than anyone previ- mots of the same size (weight or volume) ously… but we have not entirely resolved the should be similar in shape. We tested this problem… and we hope that our findings and it isn’t true (Birkhead et al. 2017a). might trigger some ideas in other researchers These results, together with the observation that might take this problem forward’. I find that the risk of rolling had been exaggerated it disappointing that many scientific journals in earlier studies, suggest that the pyriform and the scientific community are reluctant shape of guillemot eggs has not evolved to to allow authors to express such views. enable the egg to roll in an arc to minimise However, this is exactly the state of our the risk of rolling. current research on guillemot egg shape: we Deciding which of the various alternative have identified two new hypotheses, and we, hypotheses is correct requires that they all be and we hope others, will go out and test tested. This makes it difficult for researchers them. We may also identify other hypotheses to get their results published, since many sci- in the future. entific journals are reluctant to publish nega- The guillemot egg-shape story provides an tive results, even though it is essential that interesting example of the hypothetico- this information is available. A classic deductive scientific method, which in its example of systematically testing multiple idealised form comprises: hypotheses is a study of the adaptive signifi- cance of the striped pelage of the zebra Equus spp., for which there are no fewer than 18 different hypotheses (Caro 2016).

Conclusions Starting with the observation that My aim has been to present some biologically guillemot eggs are pyriform in shape, the realistic alternative hypotheses for the pyri- hypothesis was that egg shape minimised form shape of a guillemot’s egg, based on the the risk of the egg rolling off a ledge. The selection pressures created by the species’ predictions were that, by spinning like a top unusual breeding habitat and behaviour or rolling in an arc, a pyriform egg would be (Birkhead et al. 2017b). My colleagues and I less likely to roll off a ledge than a conven- identified a number of hypotheses (and there tionally shaped egg. Without any formal may be more), and we are in the process of tests (as far as I am aware), spinning like a testing these. So far, the ability to withstand top was thought by Russian biologists in the impacts, and the minimising of ‘dirt’ contami- 1940s to be untrue. Rolling in an arc was nation, seem to be the most promising alterna- tested exhaustively by Ingold (1980) and his tives to the rolling-in-an-arc idea. Since experimental results provided no support adaptations are compromises between dif- for the hypothesis. Tschanz (1990), in a ferent and often conflicting selection pressures, review of his and Ingold’s studies, also it may well be that we do not find a single stated that there was no support for the idea explanation. This, however, is the story so far.

466 British Birds 110 • August 2017 • 456–467 Vulgar errors – the point of a guillemot’s egg

Acknowledgments Caro, T. 2016. Zebra Stripes. Chicago University Press, I am grateful to my colleagues Marie Attard, John Chicago. Biggins, Mike Harris, Duncan Jackson, Bob Drent, R. H. 1975. Incubation. In: Farner, D. S., King, J. R., Montgomerie, Jeremy Mynott, Karl Schulze-Hagen, & Parker, K. C. (eds.), Avian Biology. Vol. 5, pp. 331– Jamie Thompson and Sarah Wanless for valuable 420. Academic Press, New York. conversations and comments on this manuscript. I am Gill, F. B. 2007. Ornithology. Freeman, New York. also extremely grateful to all those museums that have Harris, M. P., & Birkhead, T. R. 1985. Breeding ecology allowed us to measure their eggs; to the Wildlife Trust of the Atlantic Alcidae. In: Nettleship, D. N., & for South and West Wales for allowing me to work on Birkhead, T. R. (eds.), The Atlantic Alcidae, pp. 155– Skomer Island and to the wardens there for their 205. Academic Press, London. support. Thanks also to the Leverhulme Trust, who Hewitson, W. C. 1831. British Oology: being illustrations funded this research. of the eggs of British birds. Empson, Newcastle upon Tyne. Ingold, P. 1980. Anpassungen der Eier und des References Brutverhaltens von Trottellummen Uria aalge aalge Belopol’skii, L. O. 1961 Ecology of Sea Colony Birds of Pont. an das Brüten auf Felssimsen. Zeitschrift für the Barents Sea. Israel Program 266 for Scientific Tierpsychologie 53: 341–388. Translations, Jerusalem. [Translated from Russian] Johnson, R. A. 1941. Nesting behavior of the Atlantic Birkhead, T. R. 2008. The Wisdom of Birds. Bloomsbury, Murre. Auk 58: 153–163. London. Kaftanovski, Yu. M. 1951. [Alcidine Birds (Alcids) of the — 2016. The Most Perfect Thing: inside (and outside) a Eastern Atlantic.] Materialy k poznaniyu fauny i flory bird’s egg. Bloomsbury, London. SSSR, Novaya Seria Otdel Zoologicheskii 28(xiii): — & Nettleship, D. N. 1980. Census methods for 10–169. [In Russian] murres Uria species – a unified approach. Morris, F. O. 1856. A History of British Birds. Can. Wildl. Service Occ. Paper No. 43: 1–25. Groombridge, London. — & — 1984. Egg size, composition and offspring Romanoff, A. J., & Romanoff, A. L. 1949. The Avian Egg. quality in some Alcidae (Aves: Charadriiformes). Wiley, New York. J. Zool. Lond. 202: 177–194. Schulze-Hagen, K., Stokke, B., & Birkhead, T. R. 2009. — & — 1987. Ecological relationships between Reproductive biology of the European Cuckoo Common Murres Uria aalge and Thick-billed Cuculus canorus: early insights, persistent errors and Murres U. lomvia at the Gannet Islands, Labrador: II. the acquisition of knowledge. J. Orn. 150: 1–16. Breeding success and site characteristics. Tschanz, B. 1990. Adaptations for breeding in Atlantic Can. J. Zool. 65: 1630–1637. Alcids. Netherlands J. Zool. 40: 688–710. —, Thompson, J. E., & Biggins, J. D. 2017a. Egg shape in —, Ingold, P., & Lengacher, H. 1969. Eiform und the Common Guillemot Uria aalge and Brünnich’s Bruterfolg bei Trottellummen. Orn. Beob. 66: 25–42. Guillemot U. lomvia: not a rolling matter? Tuck, L. M. 1961. The Murres: their distribution, J. Orn. doi: 10.1007/s10336-017-1437-8. populations and biology – a study of the genus Uria. —, —, Jackson, D., & Biggins, J. D. 2017b. The point Canadian Wildlife Monograph Series No. 1, Ottawa. of a Common Guillemot’s Uria aalge egg: new Uspenski, S. M. 1958. The Bird Bazaars of Novaya hypotheses and data. Ibis 159(2): 255–265. Zemlya. Department of Northern Affairs and doi: 10.1111/ibi.12458. National Resources, Ottawa.

Tim Birkhead, Department of Animal & Plant Sciences, University of Sheffield, Sheffield S10 2TN; e-mail [email protected]

Tim Birkhead is professor of evolution and behaviour at the University of Sheffield. He has studied and written about birds for 40 years. His most recent book is The Most Perfect Thing: inside (and outside) a bird’s egg (Bloomsbury, 2016).

Correction

The following correction should be noted for Census was 1928, and the data for Grey the paper on ‘Birds and climate change’, by Herons presented in fig. 1 cover 1928–2015; James Pearce-Higgins (Brit. Birds 110: 388– hence the ticks proceed in five-year intervals 404). In fig. 1, the x-axis year labels were mis- from 1928 to 2013. For clarity, the Wren data aligned with the data at final publication, presented in fig. 2 cover the period 1966– while the caption states in error that the data 2015. span 1930–2017. The start of the Heronries

British Birds 110 • August 2017 • 456–467 467 The Carl Zeiss Award 2017

ince 1992, The Carl Zeiss Award has submission, but overall the passionate and been presented to acknowledge excep- evocative account was a huge attraction. All Stional submissions to the British Birds too often, submissions sent to BBRC fail to Rarities Committee. Currently, the award is capture the thrill of finding a top-drawer given for the best overall submission for rarity but this was not the case here. The nar- which assessment has been completed during rative is full of the drama and emotion of the the previous 12 months. Each and every event while the succinct written description record submitted to BBRC is automatically captures the essence of the bird extremely entered for the award, and BBRC voting well (fig. 1). The description was backed up members nominate submissions of particular by a couple of simple sketches (which the merit for the shortlist as and when they are observer acknowledged were not done in the assessed. The voting process is carried out field) and the Committee believed it was an ‘blind’, with all the voting members entirely plausible account given the condi- reviewing the final shortlist and giving each tions. Cases like this demonstrate that BBRC of the contenders a score from zero to five, can be collectively, and positively, responsive without knowing the score given by their col- to birds seen on a seawatch that prove impos- leagues. The scores are then simply tallied to sible to photograph. On the negative side, give an overall winner. This year, the voting some voters felt that since little could be members were joined by Andy Stoddart, the added to our collective knowledge of this BBRC Vice Chair, and Gerry Dobler from species pair, and since there could be no ZEISS, to give a panel of 12 assessors. attempt to differentiate Fea’s Pterodroma feae There are no hard and fast rules about from Zino’s Petrel P. madeira, this description what constitutes a good submission and all should not score as highly as others. members have a slightly different view about Nonetheless, reading this description should which aspects of a submission they give pri- provide anyone with an incentive to keep on ority to. However, summing the scores from a seawatching, even in the most unlikely of relatively large team of voters gives what we locations, for rare seabirds. believe is the fairest system of finding a winner. The final shortlist for 2017 was com- Hybrid Hen x Pallid Harrier, posed of six entries. All of the submissions Cambridgeshire, October 2011 to making it to that final shortlist were excellent February 2012, by Richard Thomas in one way or another, but the votes cast This submission would not have featured in showed that there was a very clear winner this competition, or indeed the BBRC report, this year. In taxonomic order, the five until recent times. The account of a hybrid runners-up in the 2017 award are as follows. Hen Circus cyaneus × Pallid Harrier C. macrourus from Cambridgeshire by Richard Zino’s/Fea’s Petrel, off Lambaness, Thomas was submitted as a pdf of an article Unst, Shetland, October 2016, published in the 2011 Cambridgeshire Bird by David Cooper Report (CBR), and that reflects a recent change We start with a rarity among submissions in BBRC policy. Back in 2011, we did not seek nowadays, namely one without photographs. records of known or putative hybrids, but that Dave Cooper has already made a name for approach changed last year and it is pleasing himself as one of Shetland’s top bird finders to see a record of this individual submitted in the relatively brief period that he’s been retrospectively. There were some decent living on Unst, and this bird will do that rep- photos and some attractive sketches presented utation no harm at all. Voters were divided, in the CBR article, which sets out the perhaps understandably, on the merits of this admirable detective job by Richard and the

468 © British Birds 110 • August 2017 • 468–475 The Carl Zeiss Award 2017 David Cooper Fig. 1. Zino’s/Fea’s Petrel Pterodroma madeira/feae, off Lambaness, Unst, Shetland, October 2016.

Footnote All the written submissions in this article are shown as submitted to BBRC and have not been edited before reproduction here.

British Birds 110 • August 2017 • 468–475 469 French Steph Hicking Fig. 2. Hybrid Hen Circus cyaneus x Pallid Harrier C. macrourus (‘Hellid’ – or Hell-ID – harrier), Cambridgeshire, December 2011. This page from Steph Hicking’s notebook shows some of the bird’s key features. The rather rounded wing shape and five ‘fingers’ (clearly visible in photographs) are both features of Hen Harrier, while the under-primary barring fits Hen rather than Northern Harrier C. hudsonius. The well-marked pale neck collar and dark boa, plus pale tips to the underside of the inner primaries are pro-Pallid features.

470 British Birds 110 • August 2017 • 468–475 The Carl Zeiss Award 2017 other observers (fig. 2). The identification was sents the first acceptable record of this highly accomplished while the bird was still present subtle species in autumn. The submission in Cambridgeshire, with the help of online contained a pleasing mix of evidence, both resources and through seeking expert feed- ‘old and new’. The photographs were not con- back, and the critical features were laid out clusive (as they could never be in autumn, at clearly. This record shows the benefits of least on current knowledge), although they looking at familiar species just that little bit certainly supported the identification. The more carefully; sometimes, you never know beautiful and comprehensively annotated just what might be lurking below the surface. watercolours captured the essence of the species from an observer renowned for being Northern Harrier, Orkney, April–June able to convey jizz in his drawings (fig. 3). 2016, by Brian Ribbands Finally, the sound files and sonograms, which Another shortlisted submission to feature a accom panied the visual evidence, nailed the harrier concerned a remarkable record from identification. This ground breaking iden ti- Orkney in the spring of 2016, when what fi cation by James McCallum and Ash eventually proved to be a Northern Harrier McElwee of an autumn Iberian Chiffchaff C. hudsonius was the subject of a failed had the full works, including a nice back- breeding attempt (with a Hen Harrier). Brian ground story to the initial discovery, and has Ribbands’ submission is a good illustration of added greatly to our knowledge of this species how, in some circumstances, a correct identi- in autumn. fication can be established only over time – in this case, a key reason for the delay was the Siberian Stonechat, Spurn, Yorkshire, concern not to disturb breeding Hen Har- October 2016, by Matt Slaymaker riers unduly. Ultimately, however, a series of This ‘Stejneger’s Stonechat’ Saxicola maurus photographs allowed the application of stejnegeri featured high on the lists of several recently established identification criteria for voters, and Matt Slaymaker was congratu- Northern Harrier, at the same time showing lated on producing a comprehensive submis- that light variability (and/or camera techni- sion that contained a good selection of calities) can render this process less than instructive photos (plates 263 & 264). The straightforward (plates 261 & 262). description was concise but thorough, with key details included as bullet points (fig. 4). Iberian Chiffchaff, Sheringham, Norfolk, Certain features were highlighted as contra- October 2016, by James McCallum dicting recent literature (e.g. the rump was A non-singing Iberian Chiffchaff Phylloscopus not strikingly pale, the underwing-coverts ibericus is a real ‘birder’s bird’, and this repre- were not black and the longest uppertail- Brian Ribbands 261 & 262. Male Northern Harrier Circus hudsonius, Orkney, April–June 2016.

British Birds 110 • August 2017 • 468–475 471 French James McCallum Fig. 3. Iberian Chiffchaff Phylloscopus ibericus, Sheringham, Norfolk, October 2016.

472 British Birds 110 • August 2017 • 468–475 The Carl Zeiss Award 2017 Steve Young/Birdwatch Steve Matt Slaymaker Matt Slaymaker 263, 264 & fig. 4. First-winter ‘Stejneger’s Stonechat’ Saxicola maurus stejnegeri, Spurn, Yorkshire, October 2016.

British Birds 110 • August 2017 • 468–475 473 French coverts lacked any streaks or dark centres), images illustrated this Brown Shrike’s Lanius and this submission has certainly helped the cristatus changing appearance in a range of Committee become more familiar with stej- lights and poses, as well as pointers to all of negeri and move closer to the point of being the classic identification features of the able to identify individuals for which there species. This was the only submission that are no genetic data. The icing on the cake for featured in the top three of every voter, and this submission was the fact that a usable was the top choice for half of the voters, thus sample of DNA was obtained from droppings making it the stand-out winner of this year’s and proved its identity as stejnegeri, putting award. this bird into the rarified category of field Michael has featured prominently in this identifications that can be backed up by DNA award before, being shortlisted a number of results. times, and runner-up in both 1997 and 1999. This year, he will be presented with the The Carl Zeiss Award 2017 winner winner’s prize, a pair of the exceptional Brown Shrike, Out Skerries, Shetland, ZEISS Victory SF 10 × 42 binoculars, at October 2016, by Michael McKee the British Birdwatching Fair at Rutland Our winner of the 2017 award is a veritable Water on Friday 18th August. Further details masterclass of the photographic submission will be posted on the BBRC website genre (fig. 5). While many ‘traditional’ (www.bbrc.org.uk) in due course, where a birders bemoan the death of the field note- selection of previous winning images can be book, there is no denying that most keen viewed along with links to the previous com- birders now carry a camera and know how to petition write-ups in BB. use it, and that this has replaced the note- book in many cases. Michael is far more than Acknowledgments just a ‘record-shot photographer’ and his use BBRC is grateful to all those observers who submit their records of rarities for consideration, either directly of a camera and presentation of the images as to the Committee or via our arrangement with a recording tool is second to none. We have websites (BirdGuides www.birdguides.com and Rare witnessed this method of submission before Bird Alert www.rarebirdalert.co.uk). We are extremely (and also from this observer), but it is always grateful to Carl Zeiss for their continued support of the interesting to see what information is high- Committee and this award. lighted. In this case, the selection of chosen

Paul French, BBRC Chairman, 1 Greenfield Bungalows, Easington, East Yorkshire HU12 0TZ; e-mail [email protected]

BritishBirdsRaritiesCommittee

BBRC is sponsored by Carl Zeiss Ltd and the RSPB Chairman Paul French, 1 Greenfield Bungalows, Easington, East Yorkshire HU12 0TZ; e-mail [email protected] Secretary Chas Holt, 307 St John’s Way, Thetford, Norfolk IP24 3PA; e-mail [email protected] Voting members Chris Batty, David Fairhurst, Paul French, Nic Hallam, Nigel Jones, Micky Maher, Richard Millington, Mike Pennington, Richard Schofield, Steve Votier Vice-Chairman Andy Stoddart • Archivist Nigel Hudson • Genetic Consultant Martin Collinson Museum Consultant Brian Small • Summariser Reg Thorpe

474 British Birds 110 • August 2017 • 468–475 The Carl Zeiss Award 2017 Michael McKee Michael McKee Fig. 5. Brown Shrike Lanius cristatus, Out Skerries, Shetland, October 2016.

British Birds 110 • August 2017 • 468–475 475 Short papers

Primary moult in Iberian Chiffchaff as a means of ageing and identification

Abstract The Iberian Chiffchaff Phylloscopus ibericus has become an annual vagrant to Britain, but in some cases the identification of this subtle species remains extremely challenging. First-winter Iberian Chiffchaffs undertake a partial moult on the wintering grounds, which includes the outer primaries, while adult Iberian Chiffchaffs do not moult primaries during their partial winter moult. A moult limit in the primaries is thus a key ageing criterion for Iberian Chiffchaffs in spring. Since neither age class of Common Chiffchaff P. collybita replaces the primaries during the partial winter moult, the presence of moulted outer primaries in spring is a potentially useful identification feature for Iberian Chiffchaff. We present data from spring birds at the Llobregat Delta, Spain, to quantify the extent of moult in 2CY (first-summer) Iberian Chiffchaffs.

This article is adapted and updated from Castelló Massip & Gil-Velasco (2013), originally published in Spanish in El Mosquitero Ibérico (Rodríguez et al. 2013).

Introduction The Iberian Chiffchaff is a rare but annual The Iberian Chiffchaff Phylloscopus ibericus visitor to Catalonia, northeast Spain, and has was, until relatively recently, a poorly known recently been removed from the Catalan Rar- taxon, a situation compounded by its former ities Committee list (Elias 2013; Rodríguez et status as ‘just’ a subspecies of Common al. 2013; CAC in press). The species is caught Chiff chaff P. collybita. The Iberian Chiffchaff and ringed annually at the Llobregat Delta breeds in Iberia but has been increasingly during spring migration. Since the area does recorded as a vagrant to Britain (47 records not lie on any direct migration route between to the end of 2015, including one breeding the species’ breeding and wintering grounds, record, all but three of those since 1999; it can be assumed that these birds are not Hudson et al. 2016). Identification criteria biased towards any particular populations. for the species, especially in terms of its sepa- Our results should thus give a good represen- ration from Common Chiffchaff, are slowly tation of the species’ moult across its range, becoming better understood. Primarily, iden- and we believe that our findings are safe to tification depends on vocalisations, plumage apply to vagrant birds in northwest Europe. and biometrics (Svensson 2001; Collinson & Melling 2008; Onrubia et al. 2013). The Moult and ageing in Iberian extent of primary moult in spring may also Chiffchaff support identification (Monteagudo 2003; Onrubia et al. (2003) showed that adult Demongin 2016) but published material is Iberian Chiffchaffs undergo a complete post- scant and many birders – and ringers – breeding moult on the breeding grounds appear to be unaware of the potential value between mid June and late August, prior to of moult patterns to help identify a vagrant migration. The post-juvenile moult also takes Iberian Chiffchaff. Here we present data from place on the breeding grounds, between late Llobregat Delta in northeast Spain which June and late August. Onrubia et al. described help to quantify the extent of primary moult the post-juvenile moult as partial, including in 2CY (first-summer) Iberian Chiffchaffs, ‘mantle feathers’ and 3–5 greater coverts. with particular emphasis on its importance Based on a sample of 12 birds trapped for ageing and identification. in northwest Spain in spring/summer –

476 © British Birds 110 • August 2017 • 476–483 Short papers including birds on migra- tion and on the breeding grounds – Monteagudo et al. (2003) found that some had replaced their outer primaries, typically P6–P10 but occasionally also P4–P5 (fig. 1, primaries numbered descendantly, i.e. P10 is the outermost), and some sec- ondaries (typically the innermost, although other secondaries were replaced in some birds) during the winter. These birds retained a variable number of juven - ile primaries, secondaries and greater coverts, and 0 10% 40% 60% 70% 80% 90% 100% all the primary coverts, allowing them to be confi- Fig. 1. Percentage of 2CY (first-summer) Iberian Chiffchaffs Phylloscopus ibericus moulting each primary; data from birds ringed dently aged as 2CY (first- in spring at the Llobregat Delta, Spain. summer) individuals. Spring migrants at the Llobregat Delta Moult in Common Chiffchaff showed a similar pattern of moult to that Common Chiffchaffs undergo a partial post- reported by Monteagudo et al. (2003). Birds juvenile moult on the breeding grounds before retaining juvenile primary coverts and a vari- migration. This typically consists of all body able number of juvenile secondaries, pri- feathers and a variable number of greater maries, and greater coverts were aged as 2CY. coverts plus, in some individuals, a number of All 2CY birds examined (n=21) showed a tertials and tail feathers. Adults undergo a moult limit in the primaries, secondaries, complete moult on the breeding grounds prior greater coverts and tertials (plate 265). Typi- to autumn migration (Svensson 1992; Jenni & cally, they had renewed some outer primaries Winkler 1994). The summer/autumn moult of and some secondaries (variable but usually Common Chiff chaff is thus similar to that of the two innermost, especially S6) during an Iberian Chiff chaff. early winter moult, with the tertials and Both age classes of Common Chiffchaff greater coverts moulted later in the winter. In undergo a partial pre-breeding moult in contrast, none of the four adult birds trapped winter, typically involving the body feathers, had moulted any of their primaries during some greater coverts, tertials and tail feathers the winter, and thus did not show a moult but no primaries (Cramp 1992; Svensson 1992; limit in the primaries (although some had Jenni & Winkler 1994; pers. obs in Spain and renewed some secondaries during the late Sweden); though see discussion below. winter; plate 266). These data suggest that the renewal of some primaries in winter – and Discussion the resulting moult limit in the primaries in Nikolaus (2000) found that more than half of spring/summer – is diagnostic of 2CY birds. 30 chiffchaffs wintering in West Africa had The frequency of replacement was assessed already moulted some primaries by early for each primary (fig. 1). All of the 2CY December, and that three birds were still in Iberian Chiffchaffs caught at the Llobregat active primary moult during that period. He Delta had moulted P9; the frequency of a par- concluded that moult takes place soon after ticular primary being moulted decreased pro- arrival on the wintering grounds in around gressively moving inwards from P9. P10 was late October. This matches with the observa- moulted less often than P9, again matching tion of an Iberian Chiffchaff in active the findings of Monteagudo et al. (2003). primary moult in December in the Gambia

British Birds 110 • August 2017 • 476–483 477 Short papers

Monteagudo (2003), we suspect that the birds described by Nikolaus as having replaced some pri- maries were in fact Iberian Chiff chaffs. At that time, Iberian Chiff chaff was not part of the Gambian List (Borrow & Demey 2012); the bird in plate 267 was documented P3 because of its appar- P2 P1 ently unusual state Joan Castelló of moult for a 265. Iberian Chiffchaff Phylloscopus ibericus, Llobregat Delta, Spain, during (Common) Chiffchaff spring migration, March 2011. The outer seven primaries (P4–P10) have but was identified been replaced during the previous winter and are darker and less worn than P1–P3 (highlighted), which are retained juvenile primaries. conclusively as Iberian Chiffchaff (S. Bayley pers. comm.; plate 267). from photographs retrospectively. Nikolaus (2000) stated that just one of the It seems likely that Iberian Chiffchaffs may 30 chiffchaffs trapped in their West African have been overlooked on their West African study was ibericus, on the basis of ‘being bright wintering grounds and that the species’ status greenish and fresh in colour’. However, it there may need to be reviewed. Some should be stressed that the identification of Common Chiffchaffs certainly reach south of Iberian Chiffchaff was in its infancy at that the Sahara in winter, and British-ringed birds time and, since the moult described fits per- have been recovered as far south as Guinea- fectly with both our findings from Iberian Bissau (Wernham et al. 2002), but it is unclear Chiffchaffs on spring migration and those of whether its sub-Saharan winter range is as extensive as suggested by, for example, Borrow & Demey (2014). The evidence from a ringing programme during spring migration at Yasmina, near Merzouga in southeast Morocco, on the northern edge of the Sahara, suggests that more than half of the chiffchaffs migrating north across the Sahara are Iberian, although at this site the proportion of each species seems to S6 vary depending on the flooding level of the José Antonio Barba 266. Adult Iberian Chiffchaff Phylloscopus ibericus in spring; Isla Grosa, nearby oasis (Gargallo et Murcia, Spain, March 2010. Note the lack of a moult limit in the al. in prep.). primaries while the innermost secondary (S6, highlighted) has been All 2CY Iberian replaced in a late-winter moult. Chiff chaffs examined in

478 British Birds 110 • August 2017 • 476–483 Short papers our study had P10 moulted at least one primary in a partial winter moult. Since there was relatively little difference in wear between retained juvenile pri- P4 maries and moulted primaries, it seems P3 that such primaries P2 are replaced early in the winter, a fact sup- P1 ported by what little moult data is avail- able for the species Sam Bayley (Nikolaus 2000; plate 267. Iberian Chiffchaff Phylloscopus ibericus, Gambia, December 2011. 267). A number of This 1CY (first-winter) bird is actively moulting P5–P9 and the tertials. secondaries may also The four inner primaries (P1–P4, highlighted), the outermost primary be moulted at the (P10, highlighted), the secondaries and all primary coverts are retained same time. Other juvenile feathers. Note that, although P9 is the most frequently moulted primary, it is not the first primary to be moulted on this bird. replaced inner sec- ondaries, together with tertials and central (Jenni & Winkler 1994) and may suggest a greater coverts, appear much fresher, sug- relatively rapid moult of the primaries (Kiat gesting that they are moulted in late winter, & Izhaki 2016). just prior to spring migration. We acknowledge that the early winter moult could be a continua- tion of the post- juvenile moult, suspended during migration; that the early winter and late- winter moults may actually be the same moult, with a period of suspension bet - ween; or that all three (post-juvenile, P6 early winter and late P7 winter) may repre- P9

P8 Thompson Andy sent physiologically 268. Iberian Chiffchaff Phylloscopus ibericus, Titchwell, Norfolk, April 2011. distinct moults. The This vocal male was initially identified by its distinctive song. With good fact that the juvenile photos such as this, the extent of primary moult can be assessed, thus primary coverts are establishing it as a 2CY (first-summer) bird. The winter-moulted P6–P9 retained, and not (highlighted) appear distinctly darker, broader, and less worn than the moulted with the comparatively browner and narrower inner primaries (P1–P5), which corresponding pri- are retained juvenile feathers. This bird, the second at Titchwell in as many years, was initially assumed to be a returning individual, but the maries, is typical of moult limit between the old juvenile and fresher moulted primaries extensive moults in show that it is in its first summer, and thus cannot be the same individual immature passerines from the previous year.

British Birds 110 • August 2017 • 476–483 479 Short papers

Any suspected Iberian Chiffchaffs in migrants in NW Africa. northwest Europe should be checked for the Hudson, N., & the Rarities Committee. 2016. Report on rare birds in Great Britain in 2015. presence of moulted outer primaries. While Brit. Birds 109: 566–631. this is easiest to detect in the hand, good- Jenni, L., & Winkler, R. 1994. Moult and Ageing in quality photographs may allow assessment of European Passerines. Academic Press, London. Kiat, Y., & Izhaki, I. 2016. Non-moulted primary coverts moulted primaries in the field (see plate 268 correlate with rapid primary moulting. J. Avian Biol. and Menzie 2011). The presence of replaced doi:10.1111/jav.00939 outer primaries, which contrast with slightly Menzie, S. 2011. Iberian Chiffchaff: spring aging and the more worn inner primaries, provides not Titchwell bird. http://birdingfrontiers.com/2011/04/ 22/iberian-chiffchaff/ only an ageing criterion but also supports the Monteagudo, A., Rodríguez, J., Carregal, X. M., Fernández, identification as Iberian Chiffchaff. G., & Pombo, A. 2003. Aportaciones al estudio de la muda en el mosquitero ibérico (Phylloscopus ibericus). References Revista de Anillamiento 12: 14–17. Nikolaus, G. 2000. Partial winter primary moult in Borrow, N., & Demey, R. 2012. Birds of Senegal and Chiffchaffs Phylloscopus collybita. Ringing & Migration The Gambia. Christopher Helm, London. 20: 31–33. — & — 2014. Birds of Western Africa. 2nd edn. Onrubia, A., Arroyo, J. L., Andrés, T., Gómez, J., Christopher Helm, London. Unamuno, J. M., & Zufiaur, F. 2003. El Mosquitero CAC (Catalan Avifauna Committee). In press. Ibérico (Phylloscopus ibericus): identificación, Actualització de la llista de tàxons homologables. biometría y apuntes sobre su migratología. Butlletí del CAC 2. Revista de Anillamiento 12: 18–29. Castelló Massip, J., & Gil-Velasco, M. 2013 Notas sobre —, Gómez, J., Andrés, T., Zufiaur, F., & Unanue, A. 2013. la muda en mosquitero ibérico Phylloscopus ibericus Identificación en mano y determinación del sexo y en un contexto de divagancia: el Delta del la edad del Mosquitero ibérico Phylloscopus ibericus. Llobregat. In: Rodríguez Martínez, N., García In: Rodríguez Martínez, N., García Fernández, J., & Fernández, J., & Copete, J. L. (eds.), El Mosquitero Copete, J. L. (eds.), El Mosquitero Ibérico. Grupo Ibérico. Grupo Ibérico de Anillamiento, León. Ibérico de Anillamiento, León. Collinson, J. M., & Melling, T. 2008. Identification of Rodríguez, N., García, J., Copete, J. L., Onrubia, A., & vagrant Iberian Chiffchaffs – pointers, pitfalls and Ramos, L. A. 2013. Distribución del mosquitero problem birds. Brit. Birds 101: 174–188. ibérico Phylloscopus ibericus en España. In: Rodríguez Cramp, S. (ed.) 1992. Birds of the Western Palearctic. Martínez, N., García Fernández, J., & Copete, J. L. Vol. 6. OUP, Oxford. (eds.), El Mosquitero Ibérico. Grupo Ibérico de Demongin, L. 2016. Identification Guide to Birds in the Anillamiento, León. [In Spanish] Hand. Privately published. Svensson, L. 1992. Identification Guide to European Elias, G. 2013 Situación del mosquitero ibérico Passerines. Privately published, Stockholm. Phylloscopus ibericus en Portugal. In: Rodríguez — 2001. The correct name of the Iberian Chiffchaff Martínez, N., García Fernández, J., & Copete, J. L. Phylloscopus ibericus Ticehurst 1937, its identification (eds.), El Mosquitero Ibérico. Grupo Ibérico de and new evidence of its winter grounds. Anillamiento, León. Bull. Brit. Orn. Club 121: 281–296. Gargallo, G., et al. In prep. The differential between Wernham, C., Toms, M., Marchant, J. H., Clark, J., the refuelling opportunities encountered south Siriwardena, G., & Baillie, S. R. 2002. The Migration and north of the Sahara can determine species- Atlas: movements of the birds of Britain and Ireland. specific stopover behaviour of spring passerine Poyser, London.

Joan Castelló Massip and Marcel Gil-Velasco, e-mail [email protected]

Primary spacing as a field identification criterion for Iberian Chiffchaff

Abstract Differences in the primary spacing between Iberian Chiffchaff Phylloscopus ibericus and Common Chiffchaff P. collybita are described, based on measurements from good-quality photographs of birds on the breeding grounds. In some situations, this may be a useful supplementary feature for field identification.

Several publications have dealt with the field 2008, McElwee 2010, Onrubia et al. 2013). separation of Iberian Chiffchaff Phylloscopus Although some plumage and structural fea- ibericus and Common Chiffchaff P. collybita tures are indicative of one species or the in western Europe (e.g. Collinson & Melling other, vocalisations and/or biometric data are

480 British Birds 110 • August 2017 • 476–483 Short papers still required by most Rarities Committees cluded that it was impossible to tell the two for acceptance of an out-of-range Iberian species apart in autumn using wing biomet- Chiffchaff record. Away from the breeding rics alone (Gordo et al. 2017). Gordo et al. did range, most birds tend to be less vocal and find differences in the relative lengths of the biometrics and an assessment of moult have primaries, although these differences were not been largely limited to birds that are exam- discussed explicitly in their paper. This article ined in the hand. A silent Iberian Chiffchaff illustrates how, with the use of good photo- in the field could easily go unidentified. graphs, the spacing between primaries on the Advances in bird photography have given closed wing can be used to help separate birders the chance to analyse details of wing Iberian and Common Chiff chaffs in the field. formula in the field, however, and to a level that was formerly possible only in the hand. Methods For example, assessment of primary spacing Since the main focus of this short paper is to in redstarts has become an established way of provide a field identification feature, only separating Common Redstart Phoenicurus photographs of birds in the field and phoenicurus from ‘Eastern Black Redstart’ P. showing the bird side-on have been ochruros phoenicuroides/rufiventris/xerophilus analysed. For each image, the bird’s primary and potential hybrids in the field (Steijn projection was measured using photo- 2005). Similar techniques were also used in editing software. Primary projection was the field identification of the Alder Flycatcher measured from the tip of the innermost Empidonax alnorum in Norfolk in 2010 visible primary to the tip of the longest (out- (DuRose 2010). ermost visible) primary; this value was taken Common Chiffchaff is generally a short- to represent 100%. The spaces between each distance migrant, with many birds wintering primary were measured, from the tip of one around the Mediterranean, while evidence is to the tip of the next, and referred to as, for increasingly pointing to Iberian Chiffchaff example, ‘space 1–2’ for the space between being a long-distance trans-Saharan migrant the tip of P1 (the innermost primary) and (Gargallo et al. in prep.). Structurally, the P2. Note that ‘space 0–1’ refers to the space wing shape of Iberian Chiffchaff is more between the tip of the longest secondary and pointed than that of Common Chiffchaff, the tip of P1. Each space was expressed as a somewhere in between that of the latter and percentage of the total primary projection. Willow Warbler P. trochilus (Catry et al. In all, photos of 30 Iberian Chiff chaffs and 2005). Although these differences have previ- 30 Common Chiffchaffs were analysed. In ously been reported as significant, and meas- each case, the identification of these birds urements from wing formulae have been fed had been confirmed by call or song before- into complex equations for the identification hand, and only birds on the breeding of Iberian Chiffchaff in the hand (Salomon et grounds and during the breeding period al. 1997; Svensson 2001), a recent article con- were analysed. Common Chiffchaffs were Martí Franch Fig. 1. Key primary spaces in Iberian Phylloscopus ibericus (left) and Common Chiffchaffs P. collybita (right).

British Birds 110 • August 2017 • 476–483 481 Short papers

Results 35% The main differences in Phylloscopus ibericus primary spacing between 30% the two species lie in the Phylloscopus collybita 25% difference between space 3–4 (the space between 20% the tip of P3 and P4) and space 4–5. Space 4–5 is the 15% largest in both species. In Iberian Chiffchaff, space 10% 4–5 and space 3–4 are similar in size, and thus 5% occupy a similar per- centage of the overall 0% primary projection (each 0–1 1–2 2–3 3–4 4–5 5–6 6–7 typically being around Fig. 2. Percentage of the primary projection occupied by each primary 20–25% of the total). space in Iberian Phylloscopus ibericus and Common Chiffchaffs P. collybita. In Common Chiffchaff, sampled from the European breeding range, space 4–5 is significantly larger than space 3–4 and are thus of the nominate race. ‘Siberian (typically around 25–30% and 17–20% of the Chiffchaff’ P. c. tristis (including ‘fulvescens’) total primary projection, respectively). shows a plumage coloration and structure Space 3–4 represented more than 20% of that is sufficiently different not to cause sig- the primary projection in only seven of the 30 nificant identification problems with Iberian Common Chiffchaffs analysed, the average Chiffchaff. However, some Common Chif f - being 18%. Correspondingly, only six of the chaffs of the race P. c. abietinus can look sur- 30 Iberians showed a space 3–4 of less than prisingly similar to Iberian in both structure 20%, with an average of 22%. Although these and coloration (pers. obs.). Since abietinus two percentages might not seem far apart, the has not been included in this study, we urge differences are sufficiently consistent to show caution in using the characteristics presented no overlap, even when the standard deviation here to separate ibericus from abietinus, at has been taken into account (fig. 2). least until further work on the latter has A preliminary assessment of some abie - been completed (see below). tinus (n=5) seems to indicate a similar per- centage length of space 3–4 to that for collybita, but a percentage of space 4–5 falling in between that for ibericus and colly- bita. Thus, the difference between the key spaces seems to be smaller in abietinus, although it still exists. In addition, there are differ- ences between the Juankar Andrés Juankar 269. The primary spacing in an Iberian Chiffchaff Phylloscopus ibericus, species in the fre- Basque Country, Spain, April 2015. Note that space 4–5 (between P4 and P5) quency of the is roughly the same as space 3–4 (between P3 and P4). number of primary

482 British Birds 110 • August 2017 • 476–483 Short papers tips visible. Although there is more overlap in this feature, the tip of P1 was visible in all 30 Iberian Chiffchaffs, whereas it was not visible in four of the 30 Common Chiffchaffs. Furthermore, the tip of P7 was visible at the wing-tip in only 14 Iberian and 16 Common (when the tip of P1 or P7 is not visible, the relative

lengths of space 0–1 Juan Bécares and space 6–7 respec- 270. The primary spacing in a Common Chiffchaff Phylloscopus collybita, tively are recorded as Llobregat Delta, Spain, April 2009. Note that space 4–5 (between P4 and 0%). As a result, the P5) is clearly longer than space 3–4 (between P3 and P4). remaining visible primary spaces increase in References the percentage of the overall primary projec- Catry, P., et al. 2005. Differential migration of chiffchaffs tion that they take up. Accordingly, on all Phylloscopus collybita and P. ibericus in Europe and Africa. J. Avian Biol. 36: 184–190. Common Chiffchaffs sampled with a space 3– Collinson, J. M., & Melling, T. 2008. Identification of 4 of more than 20%, the tip of P1 or P7 was vagrant Iberian Chiffchaffs – pointers, pitfalls and not visible. Indeed, on two individuals the tip problem birds. Brit. Birds 101: 174–188. of neither P1 nor P7 was visible. Discounting Du Rose, K. 2010. Why I’m sure the Blakeney flycatcher was an Alder. BirdGuides: the birds where the tip of P1 and/or P7 was http://birdguides.com/webzine/article.asp?a=2337 not visible on the closed wing removed any Gargallo, G. et al. In prep. The differential between the overlap in the relative size of space 3–4 with refuelling opportunities encountered south and north of the Sahara can determine species-specific stopover Iberian Chiffchaff. Any quantitative assess- behaviour of spring passerine migrants in NW Africa. ment of the primary spacing should be bal- Gordo, O., Arroyo, J. L., Rodríguez, R., & Martínez, A. anced by the number of primary tips visible: 2017. Inability of biometry to discriminate Iberian fewer visible tips increase the relative size of and Common Chiffchaffs during the autumn migration period. Ardeola 64: 49–65. the remaining primary spaces with respect to McElwee, A. 2010. Identification of an Iberian Chiffchaff the overall primary projection. Regardless of in Norfolk. Birding World 23: 150–153. the number of primary tips visible, the ratio Onrubia, A., Gómez, J., Andrés, T., Zufiaur, F., & Unanue, between space 3–4 and 4–5 in Iberian Chiff - A. 2013. Identificación en mano y determinación del sexo y la edad del Mosquitero ibérico Phylloscopus chaff will always be close to 1:1, while in ibericus. In: Rodríguez, N., García, J., & Copete, J. L. Common Chiff chaff the ratio is closer to 1:1.5. (eds.), El Mosquitero ibérico. Grupo Ibérico de The data presented here show that anillamiento, León. primary spacing can be used to give a reli- Salomon, M., Bried, J., Helbig, A., & Riofrio, J. 1997. Morphometric differentiation between male able indication of the identification of an Common Chiffchaffs, Phylloscopus [c.] collybita Iberian or Common Chiff chaff in the field. Vieillot, 1871, and Iberian Chiffchaffs, P. [c.] brehmii However, we urge that primary spacing Homeyer, 1871, in a secondary contact zone (Aves: Sylviidae). Zool. Anzeiger 236: 25–36. should be used only as one of a suite of Steijn, L. B. 2005. Eastern Black Redstarts at Ijmuiden, features to identify a potential vagrant the Netherlands, and on Guernsey, Channel Islands, Iberian Chiffchaff. Nonetheless, combined in October 2003, and their identification, distribution with suitable structure and coloration, this and taxonomy. 21: 171–194. Svensson, L. 2001. The correct name of the Iberian feature could be just enough to turn a good Chiffchaff Phylloscopus ibericus Ticehurst 1937, its but silent extralimital ibericus candidate into identification and new evidence of its winter an acceptable record. grounds. Bull. Brit. Orn. Club 121: 281–296.

Marcel Gil-Velasco, e-mail [email protected]

British Birds 110 • August 2017 • 476–483 483 Notes

Dispersive migration of a female Great Spotted Woodpecker between breeding and wintering sites in Britain Although northern populations of the Great garden bird feeder in Crick, Northampton- Spotted Woodpecker Dendrocopos m. major shire (52°20’N 01°09’W), on 26th Nov - undergo regular and often irruptive migra- ember 2014, some 99 km north of the tions (Cramp 1985; Gorman 2004), the breeding site. The bird had been appearing in British subspecies D. m. anglicus is thought to their garden for more than a week before it be highly sedentary. Data from the BTO was photographed. Even though we checked Ringing Scheme show that up to 1999 the 20 nesting females for colour rings in median distance between ringing and Wormley Wood in 2015, green/yellow was recovery sites was just 2 km and that 95% of not found breeding there. We assumed it had ringing recoveries were within 40 km of the simply moved away. However, in 2016 it was ringing site (Wernham et al. 2002). again located nesting in Wormley Wood, As part of a study of the survival of Great some 60 m from the nest where it had been Spotted Woodpeckers, a full-grown female ringed in 2014. It was paired with male was trapped at the nest in Wormley Wood, red/yellow and successfully raised two chicks. Hertfordshire (51°44’N 00°05’W), on 12th To our astonishment, female green/yellow May 2014, where it was feeding young. The appeared again in Robert and Judith Cave’s bird was given a unique colour-ring combi- garden in Crick in early January 2017 and nation (BTO/blue left, green/yellow right) was photographed on 13th. On checking the and its wing length was measured as 132 woodpecker nests in Wormley Wood on 19th mm, putting it firmly in the range for D. m. May 2017, we found it again paired with anglicus (Smith 2010). Two young left the male red/yellow, feeding three small young at nest successfully in early June. a nest just 40 m and 60 m from the sites in To our surprise, green/yellow was photo - 2016 and 2014 respectively. The male graphed by Robert and Judith Cave at their red/yellow had been trapped at the nest in Robert & Judith Cave 271. Female Great Spotted Woodpecker Dendrocopos major anglicus, Crick, Northamptonshire, November 2014 (and, inset, in January 2017); this bird was ringed at the nest site in Wormley Wood, Hertfordshire, 99 km south of Crick, in May 2014.

484 © British Birds 110 • August 2017 • 484–485 Notes the same area of Wormley Wood in 2012, the widespread feeding opportunities in when it was paired with female red/blue. It gardens has corresponded with an increase in had nested in the same small area of the the incidence of dispersive migration, which wood each year to 2017, changing partner to could be occurring at a range of scales. green/yellow in 2016 and 2017. Detailed analyses of the BTO ringing and This is the first documented case of a recovery data, alongside the retrap data that Great Spotted Woodpecker undergoing sig- are now routinely collected, may shed more nificant, repeated and directed movements light on the frequency and scale of these between breeding and non-breeding areas. movements and whether they have increased Our bird was found nesting in a small part of over time. a Hertfordshire wood in three years and over the same period was seen in a garden in Acknowledgments Northamptonshire, 99 km to the north, in We especially thank Robert and Judith Cave without whose keen observations this bird would not have two winters. Although we do not know the been found and reported in Northamptonshire. natal site of green/yellow, this appears to be a Robert and Judith discovered the likely origin of the case of ‘dispersive migration’ as described by colour-ringed bird using the excellent cr-birding.org Newton (2008). website created and run entirely voluntarily by Dirk Raes as a service to ornithology. We thank the It is surprising that this type of movement Woodland Trust, the owners of Wormley Wood, for has not been detected before in the Great their permission and encouragement to work in the Spotted Woodpecker. However, even though wood. ringers frequently retrap Great Spotted Woodpeckers at their regular ringing sites, it References is unlikely that movements such as this will Cramp, S. (ed.) 1985. The Birds of the Western Palearctic. Vol. 4. OUP, Oxford. be detected by ringing alone. In our case it Gorman, G. 2004. Woodpeckers of Europe. was systematic colour-ringing and recording Bruce Colman, Chalfont St Peter. of colour-ringed birds that detected these Newton, I. 2008. The Migration Ecology of Birds. Academic Press, London. movements. Perhaps in future the availability Smith, K. W. 2010. Continental Great Spotted and deployment of new tracking devices will Woodpeckers in Britain – further analyses of reveal even more of the complexities of wing-length data. Ringing & Migration 25: 65–70. movements such as these. Wernham, C. V., Toms, M. P., Marchant, J. H., Clark, J. A., Siriwardena, G. M., & Baillie, S. R. (eds.) 2002. It is also possible that the increasing pop- The Migration Atlas: movements of the birds of Britain ulation of Great Spotted Woodpeckers and and Ireland. Poyser, London. Ken & Linda Smith, 15 Roman Fields, Chichester, West Sussex PO19 5AB; e-mail [email protected]

Reviews

Wildlife and Wind Farms, Conflicts and Solutions (Volume 1 Onshore: Potential Effects; Volume 2 Onshore: Monitoring and Mitigation) Edited by Martin Perrow. Pelagic Publishing, 2017. Sbk, 289pp and 217pp; colour photographs. ISBN 978-1-78427-119-0; ISBN 978-1-78427-123-7; £34.99 each volume

This is a comprehensive, multi-authored overview edited to a high standard, although the academic of current knowledge, broken down into chapters style will appeal primarily to those directly covering the main taxonomic groups involved involved with this industry. (most notably birds), as well as impacts on vegeta- tion and local climate. Landscape issues are not Ian Carter dealt with. The chapters have been written and

© British Birds 110 • August 2017 • 485–486 485 Reviews

Falcons By Richard Sale HarperCollins, 2016 Hbk, 594pp; many colour photographs ISBN 978-0-00-751141-9, £59.99

A new New Naturalist volume involving birds is I thought that almost always a joy and this book is no exception. the technical and It is extremely well presented, with colour photo- mathematical graphs throughout (many taken by the author) aspects were over- and numerous high-quality colour figures and done in a few places, graphs. We should expect nothing less given the particularly in the asking price. chapter on hunting It is, in every sense, an in-depth treatment, where the author’s training as a physicist comes to stretching to almost 600 pages, the bulk of which the fore. Elsewhere, although the text is always cover the four British breeding species in separate readable, there are times when the sheer volume of chapters – essentially four mini-monographs. The detailed information presented, from many dif- rest of the book is taken up by introductory chap- ferent studies around the world, threatens to ters covering the falcon tribe, a summary of popu- swamp the reader. These sections would have ben- lation trends and status for the British species, and efited from summaries of the key, take-home, a detailed account of the use of vision and flight points from the various strands of research, and characteristics by falcons when hunting. This last greater use of tables in order to limit the number chapter contains some fascinating new insights, of facts and figures within the main text. including the early results of the author’s own Overall, this is an authoritative, comprehensive research into hunting behaviour, based on impres- and well-produced account of the British falcons. sive high-tech tags fitted to falconry birds. Falcons, It’s perhaps not a book that many will read through apparently, do not always fly directly towards their from start to finish, but it provides an excellent prey, for reasons that are explained in some detail. source of reference as well as a book to enjoy By way of a clue, I’ll reveal that fossil ammonites dipping in and out of. It is highly recommended. and Romanesco broccoli are deployed as part of the explanation. Ian Carter

Birds of Spain By Eduardo de Juana and Juan M. Varela Lynx Edicions, 2017 Hbk, 257pp; numerous colour illustrations and maps ISBN 978-84-16728-02-2; £29.99

Spain is one of my favourite birding destinations teneriffae complex from the Canary Islands, are and, through Spanish friends, I’ve long been illustrated. The text has, as might be expected, a familiar with de Juana and Varela’s Aves de España, more local focus and offers a lot of useful informa- which has recently been updated and revised. Birds tion on species’ status across the region. For me, of Spain is the English-language translation of that this is where the real value of the book lies com- book. pared with other ‘Europe-wide’ field guides that, by Coverage appears to be pretty comprehensive their very nature, need to keep a broader focus. The and includes species from the Balearic and Canary maps in Birds of Spain also offer a more detailed Islands and the North African enclaves of Ceuta view of distribution in the region. and Melilla. Illustrations vary in quality with some Travellers planning a week by the pool with being a little ‘sketchy’, though most are fine. Cer- some pre-breakfast birding thrown in probably tainly, though, none compare with the artwork in have no need to invest in this book. But for anyone the obvious field-guide rival for the region: the visiting Spain regularly and wanting to get to Collins Bird Guide. However, Birds of Spain holds its know its magnificent avifauna even better, this own well in many other areas. Non-natives, such as field guide could make a useful addition to the Red-billed Leiothrix Leiothrix lutea, are covered in suitcase. more detail than in the Collins guide, and local forms, such as the African Blue Tit Cyanistes Stephen Menzie

486 British Birds 110 • August 2017 • 485–486 Obituaries

George Richard (Dick) Potts (1939–2017)

Dick Potts was a pioneering farmland ecolo- linked them with hard-won data from the gist who made remarkable contributions to same places on predators, arable weeds, the population ecology, bird conservation and community of invertebrates in cereal crops conservation science. His scientific research and population processes in the Grey on the indirect effects of pesticides and Partridge. herbicides on farmland birds, especially the Dick was a great advocate of making sim- Grey Partridge Perdix perdix, was ground- ulation models of animal populations and breaking. Dick began these studies in 1968 using them to assess the likely effects of when he joined the Game Conservancy after envir onmental change, hunting, pollution, completing his PhD on the population predation control and conservation manage- dynamics of the Shag Phalacrocorax aristotelis ment. He used simulation models of his data at Durham University. Within a few years it to explore the effects of herbicides and insec- was clear that the meticulous, long-term ticides on the abundance of the insect food of work of Dick and his team outshone that of partridge chicks and their survival, the effects everyone else working on the topic; it paral- of predators on partridge survival and leled and complemented the then better- breeding success, and the effects of changes known research on the direct effects on birds in the amount and quality of nesting habitat, of prey of pesticides such as DDT, by Derek principally hedgerows. This approach is now Ratcliffe and Ian Newton. widely adopted, but was rare before Dick Dick was the first to realise that, in order started doing it. More important to Dick to understand declines of farmland birds, it than academic interest from ecologists in his was necessary to study farmland as an results was applying his models and data to ecosystem and to understand the structure the development of practical methods for and state of food webs comprising crop increasing the breeding population of Grey plants, weeds, invertebrates, wild birds and Partridges. His approach is set out most mammals. An essential part of his approach accessibly in the first of his monographs on was to document the way that farmers farm, the species (Potts 1986). The models were and the impacts on wild species of farmers’ used to calculate how many more partridges choices about crop types, sowing and there would be, and how many more could harvesting dates and the use of herbi- cides, insecticides and fungicides. This he was well qualified to do, putting to good use his child- hood experiences on the family farm in North Yorkshire. Dick and his team amassed informa- tion on farming practices over many years in several study areas, but

principally in a large Charlie Pye-Smith tract of Sussex 272. Dick Potts in his element, during a visit to his long-term Grey downland, and Partridge Perdix perdix study area in Sussex in July 2014.

© British Birds 110 • August 2017 • 487–488 487 Obituaries be shot, if certain insecticides and herbicides he listened, discussed and, if they had a were not used or were reduced, if numbers of point, he saw that something was done about predators of nesting partridges and their eggs it. He was courageous in drawing attention to were controlled and if more good nesting evidence that certain pesticides had harmful habitat was created. The resulting insights effects on partridge chick survival when were invaluable in triggering the develop- some in the agrochemical industry would ment of several effective practical conserva- have preferred him to stay quiet. He fully tion interventions, such as the use of accepted that gamekeepers persecute raptors unsprayed cereal field margins (conservation and published almost 20 years ago a paper headlands) to increase partridge chick food that is still cited today estimating how many supplies and survival. Where possible, inter- breeding Hen Harriers Circus cyaneus there ventions suggested to be effective by his would be in the UK if the species was not modelling were tested by conducting care- persecuted on grouse moors (Potts 1998). He fully designed field experiments, as was the did not blame raptors for Grey Partridge case for conservation headlands (Rands mortality when other factors, such as 1985) and the control of partridge predators shooters killing them by mistake, were shown (Tapper et al. 1996). However, the most far- to be more important (Watson et al. 2007). reaching effect of Dick’s enthusiasm for sim- Dick’s detailed knowledge of and curiosity ulation modelling lay in convincing other about natural history, ecology and farming applied ecologists to take the plunge. Having meant that his informed guesses about the even a simple model based upon rudimen- causes of a species’ decline or rarity, made tary data is a useful tool for improving well before any formal evidence was avail- knowledge and understanding. By developing able, turned out to be correct uncannily his partridge model step by step, he made us often. His career demonstrates that, when see that starting off with even a crude and done in the right way, scientific investigation, simplistic model of an animal population is timely reporting of results and efforts to useful in making explicit the effects of its key apply them can lead to effective changes in assumptions and deficiencies in the available policy and practice that benefit the conserva- supporting data. This then steers follow-up tion of wild birds. Dick’s ability to do this research to test and refine assumptions and while earning and maintaining the respect of collect more, better and more pertinent data. people with a wide spectrum of different It also prevents time and resources being interests and prejudices was a remarkable wasted on questions that will not make much achievement from which we should learn. difference to population outcomes. Dick died on 30th March 2017 after a short Issues at the interface of game manage- illness and is survived by his son Gareth, his ment, farming and biodiversity conservation stepson Martin and his widow Olga. are often controversial. In the current era of conflict, propaganda and fake news about References several of these topics, it is instructive to Potts, G. R. 1986. The Partridge: pesticides, predation and remember how Dick tackled them, when he conservation. Collins, London. was in the forefront of the Game Conser- — 1998. Global dispersion of nesting Hen Harriers: implications for grouse moors in the UK. Ibis 140: vancy Trust (GCT) as its Director of Research 76–88. from 1977 and Director-General from 1993 Rands, M. R. W. 1985. Pesticide use on cereals and the until his retirement in 2001. His integrity and survival of Grey Partridge chicks. J. Appl. Ecol. 22: 49–54. openness to evidence-based argument stand Tapper, S. C., Potts, G. R., & Brockless, M. H. 1996. The out in contrast to some current attitudes. He effect of an experimental reduction in predation invited independent scientists from universi- pressure on the breeding success and population ties, research institutes and conservation density of Grey Partridges. J. Appl. Ecol. 33: 965–978. Watson, M., Aebischer, N. J., Potts, G. R., & Ewald, J. NGOs to review the GCT’s research in great 2007. The relative effects of raptor predation and detail, especially when the results of a project shooting on overwinter mortality of Grey were likely to be contentious. When the Partridges in the UK. J. Appl. Ecol. 44: 972–982. reviewers said that the design of a study was deficient or a conclusion poorly supported, Rhys Green

488 British Birds 110 • August 2017 • 487–488 Recent reports Compiled by Barry Nightingale and Harry Hussey

This summary of unchecked reports covers early June to early July 2017.

Headlines There were some top-class rarities during the period, perhaps most notably a very popular Elegant Tern, which lingered along the south coast, and a short-staying Amur Falcon in Cornwall. Also in the top bracket were a White-throated Needletail in the Outer Hebrides and a Pacific Swift in North-east Scotland, while on Fair Isle there was what may yet prove to be a Green Warbler. A strong second-tier cast included a Dark-eyed Junco in Norfolk and a Yellow- rumped Warbler in Pembrokeshire, the returning White-winged Scoter appeared in the moulting seaduck flock off North-east Scotland, and the transitory Black-browed Albatross returned to Yorkshire before moving north along the English and Scottish North Sea coasts.

Black Duck Anas rubripes Strontian (High- migrans Frampton Marsh (Lincolnshire), land), long-stayer to 16th June. King Eider 7th–8th July. Somateria spectabilis North-east Scotland, long-stayer to 8th July; Carnsore Point (Co. Pacific Golden Plover Pluvialis fulva North Wexford), 22nd June; Ynyslas (Ceredigion), Ronaldsay (Orkney), 28th June. Semi- 26th June to 9th July. White-winged Scoter palmated Sandpiper Calidris pusilla North Uist Melanitta deglandi returning drake Blackdog (Outer Hebrides), 5th–6th July. Spotted (North-east Scotland), 2nd–6th July. Sandpiper Actitis macularius Buttermere (Cumbria), long-stayer to 21st June; Scaling Black-browed Albatross Thalassarche Dam (Cleveland/Yorkshire), 16th June. melanophris Bempton (Yorkshire), 28th June, Lesser Yellowlegs Tringa flavipes Blithfield same Whitburn (Co. Durham), Farne Islands Resr (Staffordshire), 29th June. Long-billed (Northumberland), Eyemouth and St Abbs Dowitcher Limnodromus scolopaceus Boulmer (Borders), Dunbar and Seacliff (Lothian), all (Northumberland), 7th–9th July. 29th June. Wilson’s Storm-petrel Oceanites oceanicus All from pelagics: off Scilly, one Caspian Tern Hydroprogne caspia A single 12th June, two 3rd July; off Co. Cork, one wide-ranging bird visited Holden Wood Resr, south of Cape Clear, 17th June, five south of 20th June and Leighton Moss (both Lan- Toe Head, 21st June. cashire & N Merseyside), 20th–21st June, Sker Point/Kenfig Pool (East Glamorgan), 25th Little Bittern Ixobrychus minutus Long-stayers June, National Wetlands Centre (Car- Cotswold Water Park (Gloucestershire), to marthenshire), 26th–29th June and 3rd–5th 8th June and (Somerset), to 4th July; also Old Moor (York- shire), 25th June. Night Heron Nycticorax nycticorax Records from Co. Dublin, East Glamorgan, Norfolk, Shropshire and Somerset. Squacco Heron Ardeola ralloides Dungeness (Kent), 11th–13th June; Killarney (Co. Kerry), 25th June. Purple Heron Ardea purpurea Records from Cornwall, Somerset, Suffolk, Co. Wicklow and Yorkshire.

Pied-billed Grebe Podilymbus podi- Richard Stonier ceps Loch Feorlin (Argyll), long- 273. Adult Elegant Tern Sterna elegans, Pagham Harbour, stayer to 5th July. Black Kite Milvus Sussex, June 2017.

© British Birds 110 • August 2017 • 489–490 489 Recent reports

July, Summer Leys then Clifford Hill GP other records from Dorset, Greater London, (both Northamptonshire), 1st July and Chew Hampshire, Kent, Somerset, Suffolk, Sussex Valley Lake (Avon), 2nd July; possibly same and Yorkshire. Red-footed Falcon Falco ves- Linford (Buckinghamshire), 9th July. White- pertinus Continuing influx with records from winged Black Tern Chlidonias leucopterus Cambridgeshire, Ceredigion, Cornwall, Records from Co. Cork, Norfolk, Northum- Dorset, Leicestershire & Rutland, Norfolk, berland, Orkney, Outer Hebrides and York- Oxfordshire, Somerset, Suffolk, Surrey and shire. Elegant Tern Sterna elegans Hayling Yorkshire. Amur Falcon Falco amurensis Island (Hampshire), 7th and 9th June, same Porthgwarra area (Cornwall), 6th–7th July. Pagham Harbour (Sussex), 10th–20th June, and Brownsea Island/Poole Harbour Lesser Grey Shrike Lanius minor Brading (Dorset), 21st–22nd June. Forster’s Tern Marsh (Isle of Wight), 22nd June. Woodchat Sterna forsteri Tacumshin (Co. Wexford), 1st– Shrike Lanius senator Records from Cornwall, 2nd July. Bonaparte’s Gull Chroicocephalus Fair Isle, Highland and Orkney. Red-rumped philadelphia Bann Estuary (Co. Derry), 16th– Swallow Cecropis daurica Records from Corn- 20th June; Oare Marshes (Kent), 8th–9th July. wall, Devon, Hampshire and Scilly.

Snowy Owl Bubo scandiacus Westray Greenish Warbler Phylloscopus trochiloides (Orkney), 21st June. White-throated Whalsay (Shetland), 7th June; Colonsay Needletail Hirundapus caudacutus Barra (Argyll), 15th June; Landguard (Suffolk), (Outer Hebrides), 22nd June. Alpine Swift 20th–21st June. Greenish or Green Warbler Apus melba Lodmoor (Dorset), 24th June. P. nitidus Fair Isle, 4th–7th July. Iberian Chiff- Pacific Swift Apus pacificus Longhaven chaff Phylloscopus ibericus Kelsall (Cheshire & (North-east Scotland), 2nd July. European Wirral), long-stayer to 28th June. Subalpine Bee-eater Merops apiaster Galmpton Warbler Sylvia cantillans Virkie (Shetland), (Devon), eight, 11th June; East Leake (Not- 11th June. Savi’s Warbler Locustella luscinioides tinghamshire), seven, 25th June to 10th July; Long-stayers Wicken Fen (Cambridgeshire), to 18th June; Hickling Broad (Norfolk), to 18th June then 3rd– 5th July; Minsmere (Suffolk), one throughout with two 20th June to 3rd July. Paddyfield Warbler Acro- cephalus agricola Mousa (Shetland), 25th June. Blyth’s Reed Warbler Acrocephalus dumetorum Fair Isle, 9th June; Siddick Ponds (Cumbria), 14th–15th June; Inverdruie (High- land), 3rd July; Nanjizal (Cornwall), 8th July.

Rose-coloured Starling Pastor roseus Records from Argyll, Cleveland, Co. Durham, Gower, Highland and Outer Hebrides. Dark-eyed Junco Junco hyemalis Stalham (Norfolk), 10th June. Black-headed Bunting Emberiza melanocephala Wembury (Devon), 4th June; Foula, 11th June, another on 15th. Rustic Bunting Emberiza rustica Fair Isle, 14th June. Yellow-rumped Warbler Setophaga Mark Rayment 274. First-summer female Amur Falcon Falco amurensis, coronata Skokholm (Pembroke - Porthgwarra, Cornwall, July 2017. shire), 18th June.

490 British Birds 110 • August 2017 • 489–490 My patch – Titchfield Haven

n the Hampshire coast, about Britain) that I found in May 2016 (plate 276). halfway between Portsmouth and Local rarities in that time have included OSouthampton, lies Titchfield Haven ‘Siberian Chiffchaff’ Phylloscopus collybita NNR. The reserve is a mosaic of mainly tristis, Wood P. sibilatrix and Marsh Warblers wetland habitats – reedbed, water meadows, Acrocephalus palustris (these three also self- man-made scrapes and the mouth of the found), Honey-buzzard Pernis apivorus, River Meon. My patch includes more than Stone-curlew Burhinus oedicnemus, Great just the official reserve, also encompassing Grey Shrike Lanius excubitor and Yellow- the seafront (Hill Head/Meon), along with browed Warbler Phylloscopus inornatus. farmland (Posbrook), a small copse (Little There are always going to be birds that you Crofton), water meadows and floods just miss – and for me, I think the most gripping beyond the reserve boundary along the canal has to be a Buff-breasted Sandpiper C. subru- path – all of which is referred to as Titchfield ficollis in September 2016. What makes it Haven by locals. That land close to the most painful is the realisation that I was just reserve has seen its share of good birds too – 300 m away, scanning the beach, blissfully most recently the Greater Yellowlegs Tringa unaware of the patch first that was flying melanoleuca that turned up on the Bridge west until it was too late! My dream birds are Street Floods in January 2015, and the Red- perhaps an albatross, cruising east past Hill rumped Swallow Cecropis daurica that spent Head, or maybe a ‘Stejneger’s Stonechat’ S. m. a couple of hours on Posbrook Flood in April stejnegeri to complete the stonechat set. Hill 2017. Head is not renowned for its seawatching, so I began patch birding in 2014 after perhaps the albatross is too much to ask for, hearing about Patchwork Challenge but Titchfield seems to be a favoured location (www.patchworkchallenge.com) while at for eastern stonechats, and has accounted for university. I decided that the Haven was far all but one of Hampshire’s four records – and more appealing than one of the parks in even that was only a few kilometres along the Southampton – and since then I’ve recorded coast. 194 species including two Black-winged Stilts Autumn has to be my favourite season Himantopus himantopus, Semipalmated since you never know what might drop in. Sandpiper Calidris pusilla, both Greater and From late August, the right conditions can Lesser Yellowlegs T. flavipes, Pallas’s yield various warblers, chats, flycatchers, Grasshopper Warbler Locustella certhiola wagtails and pipits. Evenings spent on the and two Siberian Stonechats Saxicola maurus seafront by the river can be memorable, as – one of these being the male ‘Caspian Yellow Wagtails Motacilla flava come in to Stonechat’ S. m. variegatus (the sixth for roost, sometimes in their hundreds. Early Amy Amy Robjohns 275. Titchfield Haven, Hampshire, July 2015.

© British Birds 110 • August 2017 • 491– 492 491 My patch

time can bring enjoyable and productive seawatching. Arctic Skuas Stercorarius para- siticus are annual, along with various terns and Little Gulls Hydrocoloeus minutus and Great Skuas S. skua are recorded most years but the other skuas (and shearwaters) are much harder to connect with. I missed an impressive ‘Pom day’ in 2014, but thank- fully 2016 was another good year for the Solent, and it was fantastic to watch a group of three Pomarine Skuas S. Lee Fuller pomarinus fly east on 5th May: 276. ‘Caspian Stonechat’ Saxicola maurus variegatus, Titchfield Haven, Hampshire, May 2016. my first! With the winds in the right direction, the birds were autumn is the best time for wader variety close to shore and the views were brilliant. too, when Ruff C. pugnax, Curlew Sandpiper That same evening, there was a spellbinding C. ferruginea, Little Stint C. minuta, Green T. passage of 40 Black Terns Chlidonias niger, the ochropus and Wood Sandpipers T. glareola most I’ve ever seen. Seawatching in 2017 was can appear on the scrapes. In most years an excellent by Hill Head standards too, with my Osprey Pandion haliaetus lingers, perhaps efforts yielding highlights of 20 Arctic, eight commuting between Titchfield and the Isle of Pomarine and one Long-tailed Skua S. longi- Wight, while the flocks of terns that gather caudus (mega!); the last, on 11th May, was on the beach at low tide are regularly com- just the fifth Long-tailed for the patch, three posed of up to six species. As autumn pro- of which have occurred in years ending in 7, gresses, other species begin to move through so it was right on cue! and on good days it feels as if anything can There’s plenty more highlights and good turn up. It’s brilliant when the unexpected memories from my three years of patch does happen, although enjoying a fall of birding at Titchfield Haven but hopefully this common migrants is just as satisfying. gives a flavour of what the site can produce. One day that is vivid in my memory has to The various stories from before my time are be 25th October 2015. It had been a fairly gripping, and it’s been interesting to see how quiet October in Hampshire and a walk things have changed over the years, even along the canal path with two friends early during the short time I’ve been birding the that morning had proved fruitless. Not the area. Perhaps history will repeat itself – exciting autumn day we’d hoped for, until… a second Cliff a birder approached with the news that he Swallow Petro - thought he’d seen a Great Grey Shrike. Great chelidon pyrr - Grey Shrike on the reserve? Only two pre- honota would vious records! Unsure what to think, we certainly do checked it out, and it wasn’t long before Al nicely – but exclaimed ‘I’ve got it!’ And there it was – a who knows stunning Great Grey Shrike, and showing what will turn well before it took off and headed east along up next: Titch- the coast. field Haven Another favourite time of year is late April never ceases to and early May, which is the best time for sea surprise me. passage. Despite the ‘shadow effect’ of the Isle of Wight, prolonged southeasterlies at this Amy Robjohns

492 British Birds 110 • August 2017 • 491– 492

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