Professor Martin Perrow, July 2026
By the use of introduction, I’m Professor Martin Perrow of College School London, in addition to a Visiting Scientist with the seabird group on the UK Centre for Hydrology & Ecology; each honorary titles bestowed because of my contribution to ecology within the type of some 130 scientific publications and seven books, largely throughout my 30-year profession as knowledgeable ecologist directing one of many foremost ecological consultancies within the UK. A few of my proudest achievements relate to the profitable restoration of wetlands and dealing to grasp the results of wind farms on seabirds, particularly terns. My Wildlife and Wind Farms, Conflicts and Options bookseries (Perrow 2017 ab; Perrow 2019ab) paperwork a few of this ground-breaking analysis over the past 20 years.
As a part of this work, my group and I developed a lot of modern approaches to help the understanding of the interactions between seabirds and wind farms together with ‘visible monitoring’ whereby a high-speed rigid-hulled inflatable boat is used to comply with (from 100 m or so) and observe particular person terns at sea on foraging journeys after they’d left their colonies (Perrow et al. 2011, 2017, 2019) or encountered wind farms (Harwood et al. 2017; Jones et al. 2025). This turned a non-invasive different to attaching tags to birds, which may have detrimental results particularly on light-weight species akin to terns (see Thaxter & Perrow 2019), that want all their aerial mastery to effectively catch prey and ship it to ready chicks. A key benefit of the approach is that every one behaviours will be seen and stuck by GPS, alongside all info on foraging makes an attempt and the sort and dimension of any prey captured, which, with established size to weight relationships, can be utilized to estimate the biomass of prey consumed or carried to chicks. The variations between the usually small, low calorie ‘junk’ prey consumed by adults to gas their foraging journeys and the excessive calorie, lipid-rich fish that dominate chick food plan are usually hanging.
Visible monitoring was adopted as a regular approach to assist Authorities businesses set up at-sea marine protected areas encompassing vital grounds adjoining to already protected internationally vital colonies (Wilson et al. 2014; Caldow et al. 2020). We have now tracked all 5 UK & Eire breeding species together with Sandwich Thalasseus sandvicensis, Little Sternula albifrons 쇠제비갈매기, Widespread Sterna hirundo 제비갈매기, Arctic Sterna paradisaea 북극제비갈매기 and, most not too long ago, Roseate Sterna dougalli 긴꼬리제비갈매기 (see Cabot & Nisbet 2015, Perrow et al. 2010, 2011, 2015, 2017, 2019; Seward et al. 2021). It’s honest to say we have now discovered a lot greater than was ever identified earlier than concerning the lives of all these species at sea. I’m happy to say that in 2023, I used to be in a position to share the approach with the group on the Forest Service of the US Division of Agriculture to efficiently observe the gorgeous, fascinating and thought-to-be quickly declining Aleutian Tern Onychoprion aleuticus 알류샨제비갈매기 at one among its breeding colonies in a major inhabitants focus close to Yakutat in southeast Alaska.
Since then, I’ve continued to journey, largely to feed my ardour (or is it obsession?) for terns, on a regular basis gathering materials for a potential ebook on the group and my experiences with them throughout the globe. Most not too long ago this has included Damara Tern Sternula balaenarum, a black-billed relative of Little Tern, in each Namibia and South Africa, the place it’s now critically endangered with <50 pairs, though this isn’t but recognised by its general BirdLife classification standing. This follows my position as editor and co-author on my buddy Peter Harrison’s Seabirds: The New Identification Information, printed in 2021, following our assembly in 2016 on an expedition vessel within the subantarctic islands of New Zealand. In opinions, this has been hailed “as the first seabird reference for a few years to come back. From skilled ornithologists to seasoned seawatchers, it must be required studying.”
The ‘legendary’ Chinese language Crested Tern
Given my acute curiosity in terns, Peter Harrison knew I might soar on the probability to hitch him and his buddy and colleague at Apex Expeditions, Jonathan Roussow, on a quest to see Chinese language Crested Tern Thalasseus bernsteini 뿔제비갈매기 (hereafter abbreviated as CCT for comfort).
The rationale for the search was that CCT was the one seabird species, quantity 433 or so, that Peter had not seen in 70+ years of lively seabirding across the globe. However, by probability, Jonthan had, whereas on a tour in Seram, Indonesia in December 2017. Jonathan despatched his pictures to Peter with the road “Um, Peter, I’ve discovered this tern with a wierd soiled invoice tip…”. To embark on a quest to seek out and share Peter’s final seabird, as Jonathan aptly put it, the “Final seabird for a legendary seabirder”, had been on the radar ever since. And, for private causes, 2025 needed to be the 12 months to attempt…However earlier than documenting how the search was really achieved, it’s price summarising the outstanding historical past of CCT, partly as this additionally frames and solutions the easy query of the place we have been finest to attempt to see it.
On the coronary heart of the matter, CCT has at all times been one among the ornithological enigmas of japanese Asia because the first specimen, a non-breeding fowl, was captured on 22 November 1861 at Kao, Halmahera Island, Indonesia, by German naturalist Heinrich Berstein. The collector was subsequently honoured within the species’ formal description in 1863, by his countryman, Hermann Schlegel. Few information adopted particularly within the breeding season, reinforcing its standing because the “legendary fowl” because it turned broadly identified. Intriguingly, a specimen collected in July 1917 that was initially recognized as a Higher Crested Tern 큰제비갈매기, however is now accepted as the primary Korean report of CCT (Moores 2023) indicated CCT bred within the Yellow Sea. The potential concept that CCT ought to maybe be included in a choose suite of ‘Yellow Sea breeding endemics’ that features Saunders’s Gull Saundersilarus saundersi 검은머리갈매기, Black-faced Spoonbill Platelea minor 저어새 and Chinese language Egret Egretta eulophotes 노랑부리백로, was additional evidenced by the gathering of 21 breeding birds from the Muguan Dao and Tsangkow islands (Shandong Province, Japanese China) in 1937. This turned a pivotal second because the final verified report, though odd unconfirmed stories endured, together with one within the Yellow Sea delta in September 1991. Classed as Critically Endangered by 1994, with seemingly <50 people alive (Chan et al. 2010), CCT was feared to be slipping into extinction, if this had not already occurred.
After which, on 1 June 2000, CCT was sensationally introduced again from the useless by a filmmaker (Liang et al. 2000). Chieh-teh Liang had been commissioned to boost public consciousness of the ‘Nationwide Matzu Nature Reserve for Terns’ following surveys recording giant numbers of breeding Higher Crested 큰제비갈매기, Bridled 에위니아제비갈매기 and Roseate terns 긴꼬리제비갈매기 within the Matzu Archipelago, Taiwan, a previously militarily delicate space offshore of Fujian, China. Whereas enhancing a video of a Higher Crested Tern 큰제비갈매기 colony on Zhongdao Islet, Chieh-teh Liang famous “a number of pairs of unusual terns”. After hasty session of a reference ebook, think about the joy that these smaller, paler birds with orange and black-tipped payments have been a species that had been lacking for 63 years! The next survey recognized 4 pairs and 4 chicks.
So started a outstanding conservation story. A second CCT inhabitants of 10–20 pairs was found nesting on Jiangjunmao within the Jiushan Islands off the Zhejiang Province in japanese China in 2004. Birds from this inhabitants have been additionally thought to make use of the Wuzhishan Islands to the northwest, the place they have been first recorded in 2008. In frequent with different species of terns, CCT proved adept at popping up on one other islands in response to breeding failures as 5 totally different islands have been used at Matsu and 4 at Wuzishan. In response to the important thing menace of egg-collecting for meals by native individuals (Chen et al. 2009), the Chinese language authorities started a programme of schooling and safety, and to ascertain new colonies on extra islands. Vocal playback and decoys have been used to draw Higher Crested Terns 큰제비갈매기 and thence CCT, following the logic that CCT was at all times discovered inside colonies of its way more quite a few congener. Tiedun Dao, an islet within the Jiushan Islands was the primary chosen to attempt to set up a brand new colony.
Each try was made to extend the possibilities of success as rodenticide was first used to kill off the rodents current (Lesser Ricefield Rat Rattus losea) and vegetation managed to supply the shorter grassy sward most well-liked by nesting terns. The bold venture kicked off in 2013 and located rapid success with 2 pairs of CCT nesting amongst 800 pairs of Higher Crested 큰제비갈매기 (Lu et al. 2020). The variety of CCT fledglings elevated from 1 in 2013 to 13 in 2014 and at the very least 16 from 25 pairs in 2015, the identical 12 months the same colony initiative started at Yaqueshan within the Wuzishan Islands; a web site that had beforehand held CCT amongst the Higher Crested Terns 큰제비갈매기. 5 pairs colonised and fledged 4 chicks. Six have been fledged the next 12 months, when nesting was additionally recorded on yet one more archipelago, the Penghu islands in Taiwan (Liu & Hetherington 2016). At Tiedun Dao in 2016 nevertheless, the colony was deserted early within the season. Video surveillance confirmed the consumption of eggs by King Rat Snake Elaphe carinata was the seemingly trigger (Lu et al. 2020). Because of this, a concerted effort to take away any snakes earlier than the following breeding season was undertaken. After a complete of 18 snakes have been eliminated, nesting was once more profitable in 2017 with a peak depend of 26 adults and 6 chicks fledged. There was related success at Yaqueshan with 12 adults efficiently elevating 4 chicks. As extra birds have been now being recorded nesting within the numerous islands than may very well be accounted from identified recruitment of fledglings into the inhabitants, there was good proof there was a ‘pool’ of potential breeders at giant.
And so it proved. In an extra watershed second on April 28 2016, in a digital repeat of serendipitous discovery, Republic of Korean (ROK) researchers documenting the birdlife of uninhabited islands within the Yeonggwang Archipelago in Jeollanam-do Province within the west of the nation, heard a “novel fowl vocalisation that was harsher, higher-pitched and sharper than the Black-tailed Gull calls” (Music et al. 2017). The fowl, clearly some form of tern, was positioned and adopted to a nest. ID was once more confirmed from books. A re-visit on Could 9 discovered 2 pairs of CCT on nests adjoining to one another and a fifth non-breeding particular person in attendance, all throughout the Black-tailed Gull 괭이갈매기 colony. Importantly, this was the primary verified breeding report outdoors of China and, critically, didn’t danger the problem of hybridisation with Higher Crested Tern 큰제비갈매기 that had develop into an issue additional south (Yang et al. 2018). The latter doesn’t breed this far north within the cooler, extra turbid and but productive waters powered by sediments carried by the nice Yellow and Yangtze Rivers. This factors to ecological variations between the 2 tern species in addition to the potential inclusion of CCT in a choose group of ‘Yellow Sea endemics’ like Saunders’s Gull Saundersilarus saundersi 검은머리갈매기, Black-faced Spoonbill Platelea minor 저어새 and Chinese language Egret Egretta eulophotes 노랑부리백로. A degree beforehand effectively made by Dr Moores of Birds Korea in his latest blogpost (Moores 2023).
The thought of CCT being notably tailored to situations within the Yellow Sea has been additional strengthened by aggregations of CCT on autumn stopover in Jiaozhou Bay in Qingdao, Shandong, on the Chinese language facet of the Yellow Sea from 2016. An unbelievable 128 people have been seen right here on 5 September 2023 (Chan 2024). A decade of resightings of birds ringed from Matsu documented by Wang et al. (2026) reveals CCT initially migrate north to the Yellow Sea after breeding, whereas the nice majority of Higher Crested Terns 큰제비갈매기 go instantly south. After just a few weeks, CCT then additionally disperse south; from Thailand within the east to Sarawak on the island of Borneo – the place a fowl in February 2025 was the primary in Malaysia for over a century – and northwest to the Philippines the place 3 or 4 birds have commonly been recorded in Davao, and southwest to Indonesia, together with Seram, which hosted a returning fowl for greater than a decade. It was nearly actually this person who Jonathan Roussow noticed in 2017 as described above.
The hunt for the ‘final seabird’
Returning to the search of Peter Harrison’s ‘final seabird’, the possibilities of really seeing CCT have by no means been higher. Simba Chan, long-term stalwart of CCT conservation at BirdLife Worldwide (and now working on the Japan Chicken Researcher Affiliation/Wild Chicken Society of Japan) recommended in his speak on the Workshop on Nature Conservation and Biodiversity for Transboundary Cooperation on 28–29 August 2024 in Incheon, ROK (Chan 2024), that the inhabitants is at a brand new peak of round 200 people.
However the place to attempt? Qingdao within the autumn the place birds grasp round fish cages and roost on scaffold poles would appear the good possibility. However though seeing the distinctive juveniles can be a deal with, the winter plumage of adults, like many terns, is one thing of a pale imitation of the dapper breeding plumage. Certainly a fowl in breeding finery must be the goal?
Taking into account that the important thing menace to CCT has been recognized as egg assortment and extra typically, human disturbance – amongst different threats akin to typhoons, hybridisation and most not too long ago, extremely pathogenic avian influenza (see Chan 2024) – entry to the breeding islands throughout the identified vary of CCT is understandably restricted to wardens and researchers making an attempt to preserve and perceive the birds. Encountering people at sea at any distance from the breeding islands gave the impression to be a poor prospect particularly because the foraging vary of CCT seems to be unknown, however related species like Sandwich Tern Thalasseus sandvicensis is understood to achieve at the very least 50 km from colonies, though the birds would invariably choose shorter distances if enough prey is accessible (Perrow et al. 2017). Even smaller Sterna terns akin to Arctic 북극제비갈매기, Widespread 제비갈매기 and Roseate 긴꼬리제비갈매기 might have most ranges of over 30 km when breeding. Such a spread implies that plenty of sea must be lined to have an excellent probability to see birds, particularly when the quantity concerned could be very small.
Present political tensions additionally meant that wildlife tourist-style cruises, standard in lots of different elements of the world, usually are not advisable in Taiwanese waters. In relation to seeing birds alongside the coast, for instance on public seashores, we have been conscious of a Rockjumper fowl tour that had thankfully encountered a splendid pair of CCT in early Could 2024 on a seaside in Fujian Province, most likely previous to them heading to the Matsu Archipelago to breed. However this appeared unlikely to be readily repeated. In distinction, small numbers of CCT had develop into common alongside the Gochong shoreline particularly round Gusipo seaside, southwest of Seoul, ROK, each in spring, particularly late March however by means of to early Could after which once more in late July into early August. Data on eBird from native in addition to worldwide birders confirmed sightings seemed to be linked, earlier than and after breeding, to the identified web site within the Chilsan-do islands, some 20 km away. It was thus an apparent alternative for our quest to be primarily based in ROK particularly as Dr Moores of Birds Korea alongside Birds Korea member Prof Younger-gul Kim very kindly supplied to information and help us. We have been, nevertheless, acutely conscious that our go to in the previous couple of days of Could and into early June 2025 was removed from optimum by way of earlier identified timing of incidence coupled with the truth that the variety of birds identified to attend the breeding web site on Yuksan Island could be very small, with 8 people in 2020 and seven in 2022 (see Moores 2023). Furthermore, the birds had didn’t breed on the island in 2024, with 1 pair trying to nest on a special island (Nationwide Institute of Ecology 국 립 생 태 원 2024). The latter report concludes that 10 people had been recorded since nesting was first confirmed in 2016, with 7/8 commonly current within the years since. Because it was unknown if actively breeding birds used the seaside of inshore waters round Gochang-Gusipo, we might maybe be reliant on people that have been both not breeding or had failed.
Our technique, decided by the experience of our Birds Korea guides over what’s a substantial expanse of shoreline of round 6 km, was to rotate between three areas; 1) within the north, Myeongsasimni, close to the mouth of a small watercourse, 2) the Gusipo seaside space itself and three) within the south at Goripo across the estuary mouth of a bigger watercourse; and naturally, scanning any seen areas of coast and seaside as we drove between totally different areas.
Particulars of our observations
We have been ecstatic that we have been instantly profitable on our first afternoon on 30 Could as simply over two hours earlier than excessive water, at 14.41, as whereas we have been strolling again from the ocean at space 3, a ghostly pale tern cruised up the principle channel about 150 m away and I discovered myself shouting “There it’s!” The fowl landed on one among a collection of lengthy poles within the channel to preen, revealing that’s was metallic ringed on the fitting leg and sported a white ring with two letters, ‘PB’, on its left. ‘PB’ has been identified since 2016 as the most efficient male within the inhabitants, fathering the entire six efficiently fledged chicks to 2024 (Nationwide Institute of Ecology 국 립 생 태 원 2024). Now, ‘PB’ had the beginnings of ‘receding hairline’ of white feathering throughout his brow that may be proven by actively-breeding people later within the breeding season, or generally is a signal of a transfer into non-breeding situation. Though we weren’t to realize it on the time, however following info very kindly supplied by Dr Kim Sung-Hyun (the report by Nationwide Institute of Ecology 국 립 생 태 원 2025), ‘PB’ had really tried to breed in 2025 with ‘070’, his daughter from 2022. Sadly, the resultant chick from their pairing had died. Presumably, on the time we noticed him, ‘PB’ was now not restricted to ‘central place foraging’ across the colony, though might select to attend at instances, and was free to wander extra broadly. Now, after 21 minutes, PB flew again out to sea and north across the headland. Some 18 minutes later, we discovered ‘PB’ once more on Gusipo seaside preening and loafing amongst a gaggle of Black-tailed Gulls Larus crassirostris 괭이갈매기 that proved to be omnipresent in/round Gusipo throughout our interval of statement.
Evidently, we have been all extremely excited at our sightings and the completion of Peter’s quest for his final seabird. He instantly recorded the next message:
“I’ve been seabirding ever since I used to be 6 years of age and it’s taken me nearly 80 years to get to the purpose the place I can say I’ve seen each single seabird on this planet….with the looks of the Chinese language Crested Tern …everyone thought it was completed, it was gone, but it surely got here again from the darkish abyss of extinction….and we’ve simply spent two, three days getting right here, 6,500 to eight,000 miles relying on the place we got here from.…and it was my good buddy, Martin Perrow, the editor and in addition co-author of seabirds that known as it out…and I’ve received to say…. Oh… incredible my buddy, it was simply incredible”.
There was not a dry eye on that seaside on the fruits of a dream.
The main target of our quest now shifted to extend the variety of sightings and attempt to perceive a bit extra concerning the birds. The next summarises our observations together with dates, instances, together with relative to tidal cycle (HW = Excessive Water and LW = Low Water), and notes on behaviour:
- 31 Could. Gusipo Seashore (web site 2). 08.25. 2 hrs 41 minutes after HW or 3 hrs 57 minutes earlier than LW. CCT on shoreline and bathing in sea. After 2 minutes later flew to freshwater seepage on center of seaside to preen amongst Black-tailed Gulls 괭이갈매기 that have been additionally ingesting and preening. Walked additional down seaside. Flew half approach again after 24 minutes (08.51). Particular person with no rings (i.e. unbanded) and an entire black cap aside from a white spot above the left eye and a smaller white fleck on the crown solely seen from some angles, particularly head-on. Primarily based on expertise with related, higher identified Thalasseus terns (e.g. Higher Crested T. bergii and Royal T. maxima – see e.g. Olsen & Larsson 1995), this spot together with darker smudgy markings within the worn secondaries alongside new internal primaries, aged the fowl as a third-calendar 12 months sub-adult i.e. born in 2022. The notably giant invoice indicated a male, as did its assured strutting behaviour amongst the gulls whereas it known as softly; with the bigger larids warily conceding floor. However, the one identified chick from the inhabitants in 2022 was the feminine 070 (Nationwide Institute of Ecology 2024, 2025). So, did this particular person originate from an undocumented breeding try in ROK or was it born in China? After an extra 4 minutes, the fowl flew additional down the seaside and we left.
- 31 Could. Gusipo Seashore (web site 2). 10.41. 1 hr 41 minutes earlier than LW. On return, CCT current on extensive expanse of muddy seaside amongst scattered Black-tailed Gulls 괭이갈매기. CCT confirmed as ‘PB’ with telescope. Preened earlier than roosting with head tucked into scapulars by 10.50. Asleep as clam harvesters walked previous inside 10 m or so. Human exercise elevated and ‘PB’ gave the impression to be disturbed, changing into stressed earlier than flying throughout the channel at 11.03 to take a seat on a distant breakwater by 11.05 for lower than 2 minutes, because it was disturbed by an angler selecting to arrange off the rocks. These behaviours made us surprise what number of birders anticipating CCT on the seaside as is usually recorded by ebird, miss CCT perched on different buildings.
- 1 June. Gusipo Seashore (web site 2). 08.35. 1 hr 3 minutes after HW. Noticed sitting quietly on seaside with gulls in shut proximity. Tern name, not dissimilar to ‘kerrick’ name of Sandwich Tern, heard initially from a number of hundred metres away to look of CCT in flight above seaside. Landed comparatively shut by. Confirmed as unringed third-calendar 12 months sub-adult seen beforehand, by particulars of white markings in in any other case full black cap. Preens for round 7 minutes earlier than flying nearer to the ocean. Observer left quietly at 08.42 for an additional reported sighting of a pair collectively at one other location.
- 1 June. Myeongsasimni (web site 1). c.08.30. c.1 hr after HW. Pair noticed by Dr Moores confirmed as identified ringed male, ‘PA’, and unringed feminine. Relationship as a pair strengthened by behaviour, with quick nearshore foraging journey resulting in the seize of a fish that was introduced by ‘PA’ to his mate within the method of ‘courtship feeding’ again on the seaside. Loafing Black-tailed Gulls 괭이갈매기 and a Far Japanese Oystercatcher 검은머리물떼새 current. After 43 minutes, the CCT pair left the seaside and flew off in a northwesterly path on a bearing of c.3280 within the path of an offshore island. Misplaced to view at a distance of c. 1.5 km. May there be different breeding websites (and even different birds) ready to be found?
- 1 June. Myeongsasimni (web site 1). 16.50. 1 hr 49 minutes earlier than HW. Particular person seen foraging offshore, in the end heads off on related bearing to that taken by pair in earlier statement.
- 2 June. No sightings alongside seashores from 16.56 c. 2 hrs 37 minutes earlier than HW to 18.20 at 1 hr and 13 minutes earlier than HW.
- 3 June. No sightings from 08.11, 4 minutes to HW to 09.49, 1 hr 34 minutes after HW after which from 13.06, 1 hr 8 minutes after LW.
- 3 June. Gusipo Seashore (web site 2). 18.26. 3 hrs 28 minutes after LW (4 hrs and 9 minutes earlier than HW). ‘PB’ current amongst Black-tailed Gulls 괭이갈매기 concentrated in northerly a part of seaside close to highway, by a lot human exercise on an in depth seaside. Some preening behaviour. ‘PB’ retreats from human exercise (walkers and clam collectors) after which flies additional up seaside from advancing tide. Engages in additional preening. Walks away from human walkers. Additional stretching. Tide gathers round his ft for second time. Retreats. With tide round ft for third time, stretches after which flies out to sea at 19.06.
4 June. No sightings at Gusipo Seashore from 07.02, 2 hrs and 10 minutes earlier than HW to 07.59 1 hr and 13 minutes earlier than HW.
Concluding remarks
Within the interval 30 Could to 4 June 2025, we noticed 4 totally different particular person CCT focussed on Gusipo Seashore within the bigger space from Myeongsasimni within the north to Goripo within the south. The people concerned have been the identified ringed male, ‘PB’, the identified ringed male ‘PA’ and his unringed mate, and what seems to be a beforehand undescribed particular person. The latter fowl was regarded as a male from invoice morphology and behavior and aged as in its third calendar 12 months; thus born in 2022. The one chick fledged from the identified ROK colony in 2022 was feminine and ringed, 070. The person noticed was thus both born in an undocumented web site in ROK or from one of many colonies within the a lot bigger inhabitants in China. It’s a identified phenomenon amongst a number of species of tern for youthful people to prospect different colonies away from their natal colony, presumably with the intention to breed in future ought to situations be beneficial (see Dittmann et al. 2025, Ratcliffe et al. 2008, Cabot & Nisbet 2013, Redfern et al. 2026). One mechanism to permit people to achieve distant and beforehand unknown colonies is thru mixing and social interplay at stopovers at different instances, with birds subsequently becoming a member of with teams or different people on migration. There’s apparent potential for mixing of CCT from totally different colonies and subpopulations on the numerous autumn focus in Jiaozhou Bay in Qingdao.
Our observations assist the findings of the Nationwide Institute of Ecology 국 립 생 태 원 (2025) that CCT could also be seen into the summer time interval in and round Gusipo Seashore. The notion that this might almost certainly contain non-breeding people can also be recommended by our observations. The exception to this seems to be ‘PB’, in that the Nationwide Institute of Ecology 국 립 생 태 원 (2025) report that the breeding try involving ‘PB’ included the egg being laid by his mate on Could 18 after which incubated for 30 days (i.e. to June 17) with out hatching past the identified incubation interval of 26–28 days (Lee et al. 2021). So, ‘PB’ was actively breeding within the interval our observations have been made. However the degree of dedication by ‘PB’ may very well be questioned, particularly provided that his mate, 070, was inexperienced and nesting for the primary time. Though extremely skilled, ‘PB’ can also be of unknown age though is almost certainly at the very least 13 years (breeding since at the very least 2016 when he was seemingly at the very least 3 years of age) and presumably a lot older. Terns might dwell for at the very least 30 years and there’s no present proof for outdated age (senility) lowering breeding efficiency, though this appears potential. Nonetheless, provided that ‘PB’s former mate, K00, has now chosen, and is commonly breeding with one other male, K11 (Nationwide Institute of Ecology 국 립 생 태 원 2025), this might recommend that ‘PB’s’ powers as a breeding grownup are starting to fade.
The opposite pertinent query to be thought-about is what’s the attraction of the Gusipo Seashore space and surrounds for CCT? There’s a suggestion the realm is vital as a roosting (i.e. resting or loafing together with upkeep behaviours akin to preening) and foraging space (Nationwide Institute of Ecology 국 립 생 태 원 2025). Nonetheless, provided that there was no obvious systematic try to completely describe the habitat use of both non-breeding or particularly breeding birds, the relative significance of the Gusipo Seashore space can solely be indicated as but. The truth that birds will be commonly seen within the space supplies little indication of how vital the realm is relative to different areas that aren’t surveyed, simply that it’s used. Actually, the space of 20 km from the principle breeding colony at Yuksan Islet is more likely to be effectively inside foraging vary of breeding adults, given the experiences with different terns (see Introduction above). It’s nevertheless maybe extra uncommon that terns breeding on offshore islands concentrate on waters nearer to shore, though there are examples the place this has occurred. This consists of Roseate Tern 긴꼬리제비갈매기 at Coquet Island (Robertson et al. 2014), the place inshore foraging was regarded as pushed by interspecific competitors, as each way more quite a few (c. 14-fold), sympatrically nesting Widespread 제비갈매기 and Arctic Terns 북극제비갈매기 tended to dominate the waters across the breeding island. For CCT, with out an understanding of the habitat necessities of their important prey for instance, it might show to be that different areas are way more vital as foraging grounds. Furthermore, it’s obscure the attraction of Gusipo Seashore itself particularly since birds seem like commonly disturbed, albeit unintentionally by people, although the people concerned could also be considerably acclimatised and comparatively tolerant of human presence. It may very well be that the omnipresent Black-tailed Gulls 괭이갈매기 provide vigilance and subsequently some safety from predators akin to raptors, for lone birds particularly. Furthermore, the seepage on the seaside, gave the impression to be particularly enticing and because it seems to be ‘freshwater’ (although maybe from a human supply) for ingesting and bathing/preening might symbolize a comparatively uncommon commodity immediately adjoining to the ocean. The identical could also be stated of each the opposite websites visited at Myeongsasimni and Goripo the place watercourses discharge into the ocean.
The technique of figuring out habitat use of seabirds is at the moment usually undertaken by some type of telemetry, with GPS tags immediately connecting to receiving stations within the colony by means of bluetooth know-how thereby negating the necessity to recapture birds, now broadly adopted (see Thaxter & Perrow 2019). The difficulty is that though such strategies have develop into standard for terns (see for instance, Fijn et al. 2014, Seward et al. 2021, Thaxter et al. 2024) my very own direct experiences with tagging terns (my group have been the primary to take action for each Little 쇠제비갈매기 and Sandwich Terns within the UK; Perrow et al. 2006, 2011, 2015) reveals that terns don’t reply favourably to seize and dealing with (see Perrow et al. 2011, Seward et al. 2021) and don’t carry tags simply, which has led to the trial of various attachment strategies (see Thaxter et al. 2024). Interrogation of the main points of printed research reveals that the results of tags could also be critical sufficient to imply that the findings could also be compromised. For instance, Thaxter et al. (2024) confirmed very quick intervals of contact (means of two to eight days in numerous years) with tagged birds, usually a lot shorter than the lifetime of the tag battery or seemingly attachment time. Most journey period in numerous years ranged from 9.5–33.5 hours (i.e. greater than 1 day) with maximal foraging distances of 81–292 km, all far higher than the maxima of three–4 hours and distances of as much as 50–70 km anticipated from birds attending nests the place they have been captured and tagged. It could appear that lots of the birds displaying such patterns had failed of their breeding try. Though no particulars of the end result of the breeding try are documented, the chance is that tagging was usually the first trigger. Related patterns have been beforehand proven by Fijn et al. (2014), with one Sandwich Tern captured on the nest tracked a day later some 130 km away to a seaside in a special nation. This fowl then flew again two days later at an unbelievable common velocity of 91 km/hour. A number of birds confirmed related patterns with all labelled as displaying ‘prospecting’ behaviour. Another interpretation is that birds concerned have been so severely affected by tagging to imply the breeding try was deserted and the pressured birds flew as far-off as potential within the first occasion from the perceived menace.
For a species as uncommon as CCT, the potential dangers of seize, dealing with and tagging to any particular person and thus the very small inhabitants as a complete, would appear to be unacceptably excessive. This has priority with Roseate Tern 긴꼬리제비갈매기 within the UK, the place the way more quite a few Arctic Tern 북극제비갈매기 was used as a proxy to trial tagging strategies (see Seward et al. 2021), and after detailed observations of tagged birds relative to controls revealed points, then subsequent at-sea monitoring was undertaken with the non-invasive visible monitoring (see Perrow et al. 2019). Additional work in subsequent years was then undertaken and an extra offshore protected space proposed that features Roseate Tern 긴꼬리제비갈매기 amongst a number of different seabird species (NPWS 2023). The latter was partly in response to the potential threats of proposed offshore wind farms to the most important colony for Roseate Tern 긴꼬리제비갈매기, not solely in Nice Britain & Eire, but additionally in European waters.
In my humble opinion, a substantial amount of basic crucial info akin to habitat use, foraging behaviour, prey choice of adults relative to chick provisions and potential dangers of future wind farm improvement, coupled with the idea to outline offshore protected areas for CCT could also be gathered by visible monitoring of breeding CCT, and maybe of non-breeding birds flying out to sea from the Gusipo space. If that is undertaken nevertheless, cautious consideration should be given to the scale, energy and manoeuvrability of the RIB concerned so that is optimum for the ocean situations and to make sure the standard of data gathered in addition to proportion of full tracks is as excessive as potential.
Returning to the query of the specter of current wind farms offshore of the Gusipo space and of any future deliberate websites, I might make the next factors from private expertise of in depth research on terns interacting with wind farms over >20 years within the UK and of appreciable analysis of the results and options to these results of offshore wind farms extra typically (Perrow 2019abc). As a basic stating level, offshore wind farms change nearly each facet of the marine atmosphere starting with atmospheric situations and ocean dynamics altering patterns of upwelling and downwelling influencing trophic dynamics and in the end the abundance, distribution and assemblages of plankton, fish, seabirds and marine mammals (Perrow 2019abc). The arduous substrates related to ‘fastened’ wind, the place generators are supported on monopiles or jacket foundations are colonised by sessile fauna akin to mussels, anemones or corals relying on location that will not be typical of the encircling seabed and your complete ecological construction, interactions and capabilities throughout the meals net modifications accordingly. One typical impact is that giant predatory fish affiliate with what develop into synthetic ‘reefs’. The small, pelagic forage fish which are eaten by these fish in addition to terns and different seabirds could also be disfavoured and displaced.
At a very effectively monitored web site within the UK we monitored by boat-based surveys and visible monitoring (see Introduction above) Sandwich Terns decreased their use of the wind farm space by between 32%–44% within the totally different years of operation (see Jones et al. 2024). The people that did enter the location typically took flightlines equidistant between generators clearly suggesting they have been conscious of the distances concerned and subsequently usually actively prevented the generators, not to mention getting into the rotor swept space of these generators. The noticed avoidance fee was subsequently 100%, with a precautionary avoidance fee calculated from change in behavioural responses earlier than and after building of generators calculated at the least of 98.86%. Furthermore, these birds that did enter the location considerably decreased foraging exercise to round 60percentof that recorded outdoors the wind farm,when this was similar earlier than the wind farm was constructed was constructed. It’s unknown if ‘concern’ of generators meant that terns have been much less prepared to feed or that there have been fewer appropriate prey fish current, or {that a} mixture of each elements was liable for the patterns noticed.
We will solely speculate what the results of present and future wind generators throughout the foraging vary of CCT are, or might be, though these could also be appreciable resulting in an influence on particular person health and the prospects of survival. Nonetheless, what is evident is that for such a small inhabitants, an influence resulting in the lack of even a single particular person is crucial. This magnifies the necessity for as a lot understanding as potential by means of an in depth analysis programme utilising and constructing upon the teachings discovered in western Europe particularly, which is at the moment a hub of information and knowledge.
In relation to the purpose that the lack of even a single particular person CCT would symbolize a major influence on the inhabitants degree, it’s a explanation for concern that feminine 070 appears to be the primary identified chick to recruit into the grownup inhabitants by trying to breed, albeit unsuccessfully, in 2025 in its third calendar 12 months. The query is did the opposite 5 chicks fledged by 2024 not survive? Or have they in the end nested elsewhere, both in ROK or within the bigger inhabitants in China by means of the mechanisms outlined above. No matter is the case, the shortage of apparent recruitment brings into perspective that the tiny ROK inhabitants just isn’t rising. Any potential menace at any life stage subsequently must be very fastidiously thought-about and doubtlessly managed. On the precept nesting island, Yuksan Islet, the detailed work of the Nationwide Institute of Ecology (2024, 2025) reveals the presence of two invasive species; Kudzu Pueraria montana, one of many world’s most invasive crops, and Brown Rat Rattus norvegicus, one of many world’s most invasive mammals.
In relation to the latter, unintentionally launched rats of varied species are identified to be probably the most important threats to breeding seabirds on islands, summarised within the assessment by Cities et al. (2011) as “earlier analyses pointed to Norway [Brown] rats as essentially the most harmful of the rat species for seabirds…., which signifies that every one three rat species [meaning Black or Ship Rat Rattus rattus, Pacific Rat R. exulans and Norway or Brown Rat R. norvegicus] can have devastating results, relying on circumstances…”. Normally, rats are perceived to exert the best results on small burrow-nesting seabird species, with the biggest surface-nesting species being least affected, and that eggs and chicks are focused over adults. Nonetheless, basic tendencies are arduous to ascertain as there are actually examples of seabirds nesting in all habitats, together with timber being affected and even the biggest seabirds (e.g. the nice albatrosses Diomedea spp.) being attacked by rodents. Furthermore, the precise results of rodents (e.g. by means of dietary research) relative to different elements are arduous to find out earlier than any try at rat eradication, with the outcomes after the occasion producing essentially the most compelling proof of a ‘hidden’ impact. The assessment of Cities et al. (2011) information many optimistic responses amongst seabirds that will not have been the apparent goal for rat removing, together with cliff-nesting species akin to Northern Fulmar Fulmarus glacialis, Razorbill Alca torda and European Shag Gulosus aristotelis, in addition to floor nesting species together with Bridled Tern Onychoprion anaethetus 에위니아제비갈매기 on Hardy Island within the West Indies. With a extremely endangered species akin to CCT, each egg laid and each chick hatched turns into crucial, and as such, the ‘precautionary precept’ in relation to potential predators is finest adopted. Certainly, the eradication of rats from Tiedun Dao, the preliminary focus of the CCT conservation technique in China was seen as a basic first step to securing profitable breeding and inhabitants growth on the island (Lu et al. 2020), offering a sound foundation for the same technique in ROK.
It is usually understood that Kudzu was increasing on each the principle and supplementary breeding islands (Nationwide Institute of Ecology 2025), with monitoring of this example to be continued. Nonetheless, the speedy progress fee of this plant implies that it could actually rapidly attain proportions that make it difficult and costly to regulate. As with many invasive crops, early intervention is commonly seen as the very best technique. For Kudzu, chopping and remedy with herbicide within the late summer time (i.e. after CCT has accomplished its breeding cycle) would appear to be an excellent possibility.
Having had the pleasure of spending a short while within the western a part of ROK amongst its particular birdlife and particularly CCT, probably the most magnificent and intriguing tern species I’ve encountered in my travels, I now sincerely hope and pray for the continued lengthy lifetime of the people within the tiny inhabitants and all powers potential to the conservation authorities to offer CCT the very best probability potential to flourish and in the end reclaim all seemingly breeding grounds throughout the mighty Yellow Sea.
Acknowledgements
Grateful due to Dr Kim Sung-Hyun for offering info from the Nationwide Institute of Ecology 국 립 생 태 원, with out which this put up would have been significantly diminished. On behalf of my pals and colleagues, Peter Harrison MBE and Jonathan Roussow in addition to myself, we stay indebted to the experience of Dr Nial Moores and Prof Younger-gul Kim representatives of Birds Korea for skilfully enabling our particular shared experiences with Chinese language Crested Tern, a very iconic, ‘legendary final seabird’. Thanks additionally to Dr Moores for inviting me to contribute this blogpost. I hope it stimulates additional curiosity within the continued conservation of the species, notably in ROK, and I stay out there to help in no matter approach potential.
References
Cabot, D. & Nisbet, I. (2013). Terns. The New Naturalist Library, Collins: 461pp.
Caldow, R.W.G., Perrow, M.R., Allen, D., Black, J., Bond, I., Harwood, A.J.P., Liley, D., McCullough, N., Murphy, M., Win, I. & Yates, L. (2020). Chapter 28. Verifying predictions of statistical fashions to outline the scale and form of marine Particular Safety Areas for foraging seabirds (terns). In: Humphreys, J. & Clark, R.W.E. (eds) Marine Protected Areas: Science, Coverage and Administration. Elsevier, Amsterdam, Netherlands: pp. 543–572.
Chan, S. (2024). Migratory birds: Successes within the final 30 years and new challenges. Presentation at theWorkshop on Nature Conservation and Biodiversity for Transboundary Cooperation. 28-29 August 2024. Incheon, Republic of Korea. Out there at https://www.neaspec.org/websites/default/recordsdata/2024-11/Sessionpercent202.1percent20percent28MBpercent29percent206.%20Simbapercent20Chan.pdf
Chan, S., Chen, S.H. & Yuan, H.W. (2010). Worldwide Single Species Motion Plan for the Conservation of the Chinese language Crested Tern (Sterna bernsteini ). BirdLife Worldwide Asia Division, Tokyo, Japan; CMS Secretariat, Bonn, Germany.
Dittmann, T., Zinsmeister, D., Becker, P.H. (2005). Dispersal choices: frequent terns, Sterna hirundo, select between colonies duringprospecting. Animal Behaviour 70(1): 13-20.
Harwood, A.J.P., Perrow, M.R., Berridge, R., Tomlinson, M.L. & Skeate, E.R. (2017). Unexpected responses of a breeding seabird to the development of an offshore wind farm. In: Köppel, J. (ed). Convention on Wind Vitality and Wildlife Interactions Displays from the CWW2015 convention. Springer Worldwide Publishing. pp. 19–41. ISBN 978-3-319-51270-9.
Jones, E.L., Hague, A., Skeate, E.R., Perrow, M.R., Searle, Ok.R., Scott-Hayward, L.A., Couto, A., Daunt, F., Miller, S., Delacombe, Ok., Wooldridge, T. & Butler, A. (2025). Synthesis of Proof -Closing the Loop: Feasibility research to find out a suggestions strategy for post-consent monitoring to cut back consenting danger in future assessments. BioSS/The James Hutton Institute, 2025.
Lee, Y., Kim, W., Kang, J., Yoo, S.-Y., Cha, H.-G., Lee, S.-Y. & No, D. (2021). 한국의 뿔제비갈매기(Thalasseus bernsteini) 도래 시기와 번식 현황 Arrival and breeding standing of the Chinese language Crested Tern (Thalasseus bernsteini) in Korea. Korean Journal of Ornithology 28(2): 66-74.
Liang, C.-T., Chang S.-H. & Fang, W.-H. (2000) Little identified oriental fowl: Discovery of a breeding colony of Chinese language Crested Tern. Oriental Chicken Membership Bulletin 32: 1819.
Liu, Y.C. & Hetherington, W. (2016). Uncommon terns noticed round Penghu. Out there right here
Lu, Y.W., Roby, D.D., Fan, Z.Y., Chan, S., Lyons, D.E., Hong, C.-H., Wang, S., Yang, J., Zhou, X., Chen, D., Yuan, H.-W. & Chen, S. (2020). Making a conservation community: Restoration of the critically endangered Chinese language crested tern utilizing social attraction. Organic Conservation 248: 108694.
Moores, N. (2023). The Chinese language Crested Tern 뿔제비갈매기 in Korea. Birds Korea Weblog. April 2nd 2023. Out there at https://www.birdskoreablog.org/?p=27008
Nationwide Institute of Ecology 국 립 생 태 원 (2024).국 제 적 멸 종 위 기 종 뿔 제 비 갈 매 기 번 식 생 태 및 서 식 지 연 구 ( 3 차 년 도 ) Breeding ecology and habitat traits of the Chinese language Crested Tern, Critically Endangered Species. 연 구 보 고 서 ( 연 차 NIE-B-2024-13: 108pp.
Nationwide Institute of Ecology 국 립 생 태 원 (2025). 국 제 적 멸 종 위 기 종 불 제 비 갈 매 기 번 식 생 태 및 서 식 지 연 구 ( 4 차 년 도 ) Breeding ecology and habitat traits of the Chinese language Crested Tern, Critically Endangered Species. 연 구 보 고 서 ( 연 차) NIE-B-2025-13: 126pp.
Nationwide Parks and Wildlife Service (NPWS) (2023). Conservation Aims: North-west Irish Sea SPA 004236.
Model 1. Nationwide Parks and Wildlife Service, Division of Housing, Native Authorities and Heritage: 45pp. Out there at https://www.npws.ie/protected-sites/spa/004236
Olsen, Ok.-M. & Larsson, H. (1995). Terns of Europe and North America. Princeton College Press: 207pp.
Perrow, M.R. (ed) (2017a). Wildlife and Wind Farms, Conflicts and Options Quantity 1 Onshore: Potential Results. Pelagic Publishing, Exeter, UK: 289pp.
Perrow, M.R. (ed) (2017b). Wildlife and Wind Farms, Conflicts and Options Quantity 2 Onshore: Monitoring and Mitigation. Pelagic Publishing, Exeter, UK: 217pp.
Perrow, M.R. (ed) (2019a). Wildlife and Wind Farms, Conflicts and Options Quantity 3 Offshore: Potential Results. Pelagic Publishing, Exeter, UK: 291pp.
Perrow, M.R. (ed) (2019b). Wildlife and Wind Farms, Conflicts and Options Quantity 4 Offshore: Monitoring and Mitigation. Pelagic Publishing, Exeter, UK: 330pp.
Perrow, M.R. (2019c). A synthesis of results and impacts. In Perrow, M.R. (ed). Wildlife and Wind Farms, Conflicts and Options Quantity 3 Offshore: Potential Results. Pelagic Publishing, Exeter, UK: pp. 235–277. In: Perrow, M.R. (ed). Wildlife and Wind Farms, Conflicts and Options Quantity 4 Offshore: Monitoring and Mitigation. Pelagic Publishing, Exeter, UK: pp. 96–134.
Perrow, M.R., Skeate, E.R. & Gilroy, J.J. (2011). Novel use of visible monitoring from a rigid-hulled inflatable boat (RIB) to find out foraging actions of breeding terns. Journal of Area Ornithology 82: 68–79.
Perrow, M.R., Harwood, A.J.P, Berridge, R.J. & Skeate, E.R. (2017). The foraging ecology of Sandwich Terns in north Norfolk. British Birds 110: 257-277.
Perrow, M.R., Gilroy, J.J, Skeate, E.R. & Mackenzie, A. (2010). Quantifying the relative use of coastal waters by breeding terns: in the direction of efficient instruments for planning and assessing the ornithological impacts of offshore wind farms. ECON Ecological Consultancy Ltd. Report back to COWRIE Ltd. ISBN: 978-0-9565843-3-5. Out there from: http://www.thecrownestate.co.uk/media/5999/cowrie-quantifying-the-relative-use-of-coastal-waters-by-breeding-terns.pdf
Perrow, M.R., Skeate, E.R., Traces, P., Brown, D. & Tomlinson, M.L. (2006). Radio telemetry as a instrument for influence evaluation of wind farms: the case of Little Terns Sterna albifrons at Scroby Sands, Norfolk, UK. Ibis: 148 (Suppl. 1): 57-75.
Perrow, M.R., Harwood, A.J.P., Skeate, E.R., Praca, E. & Eglington, S.M. (2015). Use of a number of knowledge sources and analytical approaches to derive a marine protected space for a breeding seabird. Organic Conservation 191: 729–738.
Perrow, M.R., Harwood, A.J.P, Berridge, R.J, Burke, B. Newton, S. & Piec, D. (2019). Foraging and chick-provisioning ecology of Roseate Terns breeding at Rockabill, in Eire. British Birds 112: 496–516.
Ratcliffe, N., Newton, S., Morrison, P., Merne, O., Cadwallender, T. & Frederiksen, M. (2008). Grownup survival and breeding dispersal of Roseate Terns throughout the Northwest European metapopulation. Waterbirds 31(3): 320-329.
Redfern, C.P.F., Metal, D. & Morrison, P.G. (2026). Natal philopatry, dispersal and age of first breeding in relation to dimension and intercourse of Arctic Terns (Sterna paradisaea). Ibis 168: 79–94.
Robertson, G.S., Bolton, M., Grecian, W.J., Wilson, L.J., Davies, W. & Monaghan, P. (2014) Useful resource partitioning in three congeneric sympatrically breeding seabirds: foraging areas and prey utilization. The Auk 131(3): 434-446.
Seward, A., Taylor, R.C., Perrow, M.R., Berridge, R.J., Bowgen, Ok.M., Dodd, S., Johnstone, I. & Bolton, M. (2021). Impact of GPS tagging on behaviour and marine distribution of breeding Arctic Terns Sterna paradisaea. Ibis 163: 197–212.
Music, S.-Ok., Lee, S.W, Lee, Y.Ok., Lee, S.Y., Kim, C.H., Choi, S.S., Shin, H.C., Park, J.Y., Lee, J.H., & Kim W.-Y. (2017). First report and breeding report of the Chinese language Crested Tern Thalasseus bernsteini on the Korean Peninsula. Journal of Asia-Pacific Biodiversity 10: 250–253.
Thaxter, C.B. & Perrow, M.R. (2019). Chapter 4. Telemetry and monitoring of birds. In: Perrow, M.R. (ed). Wildlife and Wind Farms, Conflicts and Options Quantity 4 Offshore: Monitoring and Mitigation. Pelagic Publishing, Exeter, UK: pp. 96–134.
Thaxter, C.B., Inexperienced, R.M.W., Collier, M.P., Taylor, R.C., Middelveld, R.P., Scragg, E.S., Wright, L.J., Cook dinner, A.S.C.P. & Fijn, R.C. (2024). Behavioural responses of Sandwich terns following the development of offshore wind farms. Marine Biology 171:58.
Cities, D.R., Byrd, G.V., Jones, H.P., Rauzon, M.J., Russell, J.C. & Wilcox, C. (2011). Impacts of launched predators on seabirds. In: Mulder, C.P.H., Anderson, W.B., Cities, D.R. & Bellingham, P.J. Seabird islands: Ecology, Invasion and Restoration. Oxford College Press, UK: pp. 56–90.
Yang, J., Chen, G., Yuan, L., Huang, Q., Fan, Z., Lu, Y., Liu, Y. & Chen, S. (2018). Genetic proof of hybridization of the world’s most endangered tern, the Chinese language Crested Tern Thalasseus bernsteini. Ibis 160: 900–906.
Wang, S., Ding, P., Lu, Y., Zhou, X., Yan, Z., Qiana, C. & He, Ok. & Fan, Z. (2026). Decadal banding efforts repay: Assessing Chinese language Crested Tern conservation by means of resighting knowledge. Avian Analysis 17: 100329.
Wilson L. J., Black J., Brewer, M. J., Potts, J. M., Kuepfer, A., Win I., Kober Ok., Bingham C., Mavor R. & Webb A. (2014). Quantifying utilization of the marine atmosphere by terns Sterna sp. round their breeding colony SPAs, JNCC Report 500, ISSN 0963 8901.
