Dr. Nial Moores, Kim Eojin and Kim Haemin.
Almost 90 hours of visible migration counts over 16 dates in Daehang, Gadeokdo, Busan, this September resulted in 12,837 -17,117 individual birds counted, with the five most numerous species Chinese Sparrowhawk Tachyspiza soloensis 붉은배새매 (7,604-11,046); Pacific (Fork-tailed) Swift Apus pacificus 칼새 (1,648-1,907); White-throated Needletail Hirundapus caudacutus 바늘꼬리칼새 (757-957); “Large White-headed Gulls” (1,330); and Black-tailed Gull Larus crassirostris 괭이갈매기 (650-700).
A total of 94 bird species were identified from our fixed observation point (at: 35.0105°, 128.8293°) during these 16 dates of research. These included a Crested Ibis on most dates (presumably from the introduction program at Upo Ramsar site); single Far Eastern Curlew, Long-tailed Jaeger, Common Tern and Eurasian Spoonbill; between four and ten Osprey and 13-22 Crested Honey Buzzard; and two Eastern Marsh Harriers and two Amur Falcon (latter rather rare in the southeast).
In accordance with guidance provided through the International Civilian Aviation Organisation, we also gathered information on flock size, flight direction and estimated flight of height. Our count method allows us to share that during our research there were between 25,322 and 30,952 “crossings” of birds over only about 1.2km of the proposed runway area and its immediate approach, at an average of between 4.7 and 5.7 birds per minute of observation. Of course, this total will have been much higher if we had been able to count every day through the month; and count birds across the whole length of the proposed runway and its approach.
As during previous research efforts at Gadeokdo, counting was conducted each day from a fixed point overlooking the proposed runway area (=Daehang Village) by Nial Moores (National Director of Birds Korea), using the same methods as outlined during earlier research. In addition, videoing and photographing was conducted each day by Kim Eojin (Korea’s most famous independent bird YouTuber – and also a Birds Korea member) with “spotting” and photographing also conducted on multiple dates by Kim Haemin (also a Birds Korea member, who drove down specially from Seoul three times to witness the spectacle!). On most days, both KE and KH watched from the top of Yeondaebong, a 460m high hill overlooking the same village, communicating by walkie talkie with NM. Our research was also joined on two or more dates by several additional birders from the southeast.
At least now the importance of Gadeokdo to migratory birds is starting to become properly and widely recognised – as is public recognition of the need to do appropriate research for assessing the bird strike risk.
Southward Migration of the Chinese Sparrowhawk
Until now, even most birders in Korea probably thought of the Chinese Sparrowhawk largely as a local summer visitor to forested valleys with rice-fields, where birds often sit up prominently on poles and tree snags. Few birders – at least before this survey – seemed to have even heard about the migration route which these birds use during southward migration – out from the southeast (between Geoje and Busan) across the sea to Teimado / Tsushima; and from there on down through western Japan and the Nansei Shoto onto Taiwan and the Philippines south into Indonesia. Perhaps this is why the Environmental Impact Assessment for the proposed Gadeokdo airport did not even include any counts from September, when this species’ southward migration peaks?
This lack of attention to this migration route, especially from central government bodies as they developed the Gadeokdo airport proposal, is genuinely surprising. This migration route has in fact been known about for decades. The section of the route through western Japan, for example, was first identified at least fifty years ago (Brazil 1991); and has since been confirmed every year this century by birders on Teimado/ Tsushima, with e.g., a five-year geometric mean of counts there from 2000-2004 of 82,874 individuals (and a remarkably similar 82,868 per year for the years 2021-2025 too). In addition, the main migration routes through Asia, including the route through the southeast of the ROK to Japan, were also depicted 15 years ago in Germi et al. (2009).
Within the ROK itself, almost 25 years ago now, Park Jin-Young wrote in his doctoral thesis (on p. 224, in his account of Chinese Sparrowhawk) that “it is certain that large groups will pass through the southeastern part of the Korean peninsula”, even though he acknowledged that, “no specific investigation has been conducted so far” (Park 2002). Shortly after, as part of his work within the Ministry of Environment, Dr Park Jin-Young therefore sub-contracted several researchers in September 2002 and 2023 to help to identify this route. These researchers included Dr Kim Su-Kyung (one of Birds Korea’s four co-founders) and NM. In September 2002, Dr Kim Su-Kyung observed more than 500 Chinese Sparrowhawk in a single flock in Busan (at that time, by far the largest flock of this species known in the ROK); and the following year, as part of this same government-funded count initiative, NM counted 936 Chinese Sparrowhawk on September 14th and 1,200-1,700 Chinese Sparrowhawk on September 15th over Mount Bongnae in Busan. The fact that thousands of Chinese Sparrowhawk migrate through Busan during southward migration has therefore been known about, including by central government, for more than two decades.
Even at Gadeokdo itself, back in 2021, NM counted 2,358 Chinese Sparrowhawk on September 18th over the proposed runway area. This count was shared at the time on social media; and was included in a report which has subsequently been made widely available in both English language and Korean language versions. The English-language version can still be downloaded toward the bottom of this post. Counts made back in 2021 were also referenced in an opinion submitted as part of the proposed Gadeokdo airport EIA process.
What do these counts mean?
Counts of this kind have two main uses: first, for improving understanding of bird migration and of species; and second, for helping to assess the bird strike risk at proposed airport sites.
We therefore hope to use these counts to stimulate more visible migration research, including in the south-east of Korea, and to encourage greater communication between birders here with others along the Flyway – in Japan and Taiwan and to the south.
We also very much hope that these counts will be considered properly by the Ministry of Land, Infrastructure and Transport and by other decision-makers when they continue to assess the potential risk of bird strike at this location. We would be delighted to provide these count data free of charge to the ministry and, if asked, to support these data with a much fuller explanation of count methods. We also remain willing if contracted to train other researchers in conducting visible migration counts of this kind, so that they can do more than just take photos of birds as they pass by. Certainly, similarly intensive and detailed research is required at Gadeokdo during the remainder of the southward migration period (with e.g., the peak of Grey-faced Buzzard expected in early October; and e.g., the passage of Eastern Buzzard, Eurasian Sparrowhawks and Brown-eared Bulbul flocks in late October and of Rook in November), as during the northward migration period too.
This type of offer to support decision-makers and interested parties with best information has a long history: indeed they are part of Birds Korea’s rationale . As such, we already made similar offers about our Gadeokdo count data several years ago, well before the disastrous air crash in Muan at the end of 2024 and the subsequent court ruling against the Saemangeum New Airport in July 2025 – in large part because the bird strike risk was considered not to have been properly assessed. We continue to make a similar offer too in relation to sharing of our data as they relate to the site of the proposed airport on Baengyeong Island (as proposed, immediately next to an internationally important wetland for waterbirds, within a migration hotspot where 400 species of bird have been recorded); and as we stated in a meeting at the National Assembly earlier this year, we remain willing to meet with decision-makers to explain the bird strike risk associated with building an airport within the internationally important Hwaseong Wetlands too.
This bird research at Gadeokdo, as at the sites of several other proposed airports, provide many thousands of reasons for suspending construction and for conducting a full reassessment. If airports really need to be built, then the environmental impact assessments for them need at an absolute minimum to include detailed research by experienced researchers conducted throughout the year, supported by radar studies. Following the terrible crash at Muan, does anyone disagree?
eBird Checklists are available for September 8th, September 10th, September 12th, September 14th, September 15th, September 16th, September 17th, September 18th, September 19th, September 21st, September 22nd, September 24th, September 25th, September 26th, September 27th and September 29th.
References
Brazil, M. 1991. The Birds of Japan. Published by Helm.
Germi, F., Young, G. S., Salim, A., Pangimangen, W. & Schellekens, M. 2009. Over-ocean raptor migration in a monsoon regime: spring and autumn 2007 on Sangihe, North Sulawesi, Indonesia. Forktail 25: 105-117.
Park J-Y. 2002. Current status and distribution of birds in Korea. Unpublished doctoral thesis, Kyung-Hee University.