Asan Bay and Hwaseong Wetlands FNS: March 29-31

Birds news from Nial Moores (Birds Korea) and Jung Hanchul (Gyeonggi KFEM and Birds Korea member).

Highlights in the FNS during further survey for the EAAFP Hwaseong Wetlands Project funded by Hwaseong City included a single Long-billed Dowitcher (our 111^th waterbird species recorded there since late June 2020), displaying Saunders’s Gull, several groups of Bohai-type Black-tailed Godwit, a close-in pod of Finless Porpoise, at least 1855 Far Eastern Curlew and more than a thousand each of Great Knot and Bar-tailed Godwit…

In the Asan Bay Reclamation Area during the high tide of the 29^th, we counted 13,305 shorebirds, with the four most numerous species Dunlin (11,700), Grey Plover (1062: meeting the 1% of a population criterion), Eurasian Curlew (188) and Far Eastern Curlew (171) and the least expected find a single Red-necked Stint: an exceptionally early individual.

Thanks to fog and severe yellow dust, counts in the Hwaseong Wetlands Flyway Network Site were divided over two increasingly warm days, with counts of all waterbirds on the 30^th followed by more focused survey of shorebirds on the 31^st. In all a minimum 25,205 waterbirds were counted, with greatly reduced numbers of geese and duck (which included e.g., 85 tardy Ruddy Shelduck and the first six Garganey of the year), and much larger numbers of shorebirds than in mid-March, with surprisingly high diversity.

In the Hwaseong Flyway Network Site, notable counts / species included:

Black-necked Grebe Podiceps nigricollis 검은목논병아리. At least 113, with most in breeding plumage and several in active display.

Black-winged Stilt Himantopus himantopus 장다리물떼새. Nineteen were counted: the personal first of the year here.

Far Eastern Curlew Numenius madagascariensis 알락꼬리마도요. 1,855 were counted on the 30^th and 1,834 on the 31^st.  This is almost 6% of the estimated global population of this fast-declining, globally Endangered species. On-site threats to this species largely relate to roost sites (see e.g., here).

Eurasian Curlew Numenius arquata 마도요. A total of 2,860 were counted on the 30^th (>2% of the Flyway population of this globally Near Threatened species).

Bar-tailed Godwit Limosa lapponica 큰뒷부리도요. Only 53 were counted at roost in the evening on the 30^th. This number had increased massively to 860 by the morning of 31^st, increasing further to 1,180 by the evening. Although some birds might have been missed on the 30^th, a very large arrival clearly took place during this survey period. All birds which were seen well were of subspecies baueri.

Black-tailed Godwit Limosa limosa 흑꼬리도요. A total of 61 were counted, with the largest group 36. All looked large and long-billed; most showed only weak-toned breeding plumage. As our main northward migration of the small, short-billed melanuroides Black-tailed Godwit is concentrated in early May, it can only be assumed that most or all of these are of the newly-described larger bohaii subspecies (an otherwise excellent paper by Zhu et al. 2020 on the discovery of this taxon oddly excludes mention of records of larger birds in the ROK, which date back at least to 2011, when assessed as “limosa sp?”).

Great Knot Calidris tenuirostris 붉은어깨도요. Only 44 of this globally Endangered species were counted on the 30^th. However, this number had increased to 1,082 by the evening of 31^st.

Dunlin Calidris alpina 민물도요. On 30^th, 11,100 and on 31^st 11,500 were counted at roost (though with birds spread along more than 2km of shoreline, these counts might not be very accurate).

Long-billed Dowitcher Limnodromus scolopaceus 긴부리도요.  A rare migrant and even rarer over-wintering species in Korea, one was seen during the evening of the 31^st. This is at least the second record of this species in the FNS (one was “well-twitched” back in 2008 or thereabouts).

Common Snipe Gallinago gallinago 꺅도요. The first two of the year were heard on the 31^st.

Common Redshank Tringa totanus 붉은발도요. At least 17 were back in the FNS: our first here this year.

Spotted Redshank Tringa erythropus 학도요. A total of 116 were counted in the FNS on the 30^th.

Saunders’s Gull Chroicocephalus saundersi 검은머리갈매기. Fifty-six were counted in the evening of 31^st. More remarkable was two or more pairs of this globally Vulnerable species displaying very actively and investigating potential nest sites on both 30^th and 31^st. The species was first found nesting in the ROK in the nearby Shihwa Reclamation area back in 1998 (Moores 1999). Since that time they have been proven to nest at least in Song Do and on Yeongjong (both Incheon) and in or immediately adjacent to the Saemangeum reclamation area.

Oriental Stork Ciconia boyciana 황새. Only one was seen:  released individual E44.

Black-faced Spoonbill Platalea minor 저어새. At least 35 of this globally Endangered species were back in the FNS on 31^st.

In addition to Korean Water Deer (both seen and heard), we also observed ten or more Narrow-ridged Finless Porpoise Neophocaena asiaeorientalis 상괭이 feeding close to the outer sea-dyke on 31st. This species is currently assessed as globally Endangered; with evidence of very rapid declines in ROK marine waters.

References

Moores, N. 1999. Saunders’s Gull colony in South Korea: first nesting record outside of the People’s Republic of China. OBC Bull 28, Nov 1999: 43-49.

Zhu, B.R., Verkuil, Y.I., Conklin, J.R., Yang, A., Lei, W., Alves, J.A., Hassell, C.J., Dorofeev, D., Zhang, Z. & Piersma, T. 2020. Discovery of a morphologically and genetically distinct population of Black‐tailed Godwits in the East Asian‐Australasian Flyway IBIS. DOI: 10.1111/ibi.12890.