Distribution, breeding status, and conservation of the black-faced spoonbill (Platalea minor) in South Korea

Abstract

This study was conducted to determine the distribution and breeding status of the black-faced spoonbill (Platalea minor) for conservation and management purposes in South Korea. Breeding and stopover sites of the black-faced spoonbill were mainly in uninhibited islets off the west coast of the Korean Peninsula; wintering sites were observed on Jeju Island. Between April and July 2013, we observed 638 black-faced spoonbill nests along the west coast of the Korean Peninsula. Most of the nests were observed in the Gyeonggi Bay area, on Kujido Islet, Bido Islet, Namdong retaining basin, Youdo Islet, Suhaam Islet, Seomando Islet, and Maedo Islet, which were major breeding sites for these birds. It is essential to understand the distribution, breeding status, ecology, and habitat patterns of the black-faced spoonbill, based on existing data, for the conservation and management of this species. Long-term ecological research on the population dynamics of the black-faced spoonbill is needed to implement a successful conservation strategy.

Keywords:

• black-faced spoonbill
• conservation
• nest
• population
• uninhibited islet

Introduction

Understanding the distribution and breeding status of a species is essential to its conservation and management. In particular, information on endangered species is very useful for developing a conservation strategy for the animal and its habitats. Basic ecological field data on endangered species should be obtained within a species’ natural habitat (Lee et al. 2010). Little is known about the ecological attributes of many endangered birds, including demographic history, breeding ecology, behavior, and habitat use. Such information is necessary to evaluate potential threats and to develop action plans that will ensure the future survival of a species in its own habitat (Yeung et al. 2009).

The black-faced spoonbill (Platalea minor) is a critically endangered migratory wader (Ueta et al. 2002). Globally, it is estimated to have a population size of 2700 individuals (National Research Institute of Cultural Heritage 2013). Most black-faced spoonbills breed in small colonies on uninhibited islets along the west coast of the Korean Peninsula, and can be found in the winter spoonbills are found in South Korea, Japan, Taiwan, Vietnam, China, Philippines, and Thailand (Kennerly 1990; BirdLife International 2001; Choi et al. 2007; Ueng et al. 2007). This bird has been designated as an endangered species by the International Union for Conservation of Nature (IUCN), and as Natural Monument No. 205-1 by the Cultural Heritage Administration of Korea (Oh et al. 2009).

The size of the black-faced spoonbill population declined dramatically during the Korean War (del Hoyo et al. 1992), which resulted in the destruction of breeding sites and disturbed breeding colonies. Moreover, loss of suitable habitats as well as environmental pollution caused by economic development in Asian countries may also have been major factors in the reduction of the population (Yeung et al. 2006; IUCN 2014). Increased public and governmental efforts that aim to conserve birds and their habitats have resulted in a steady increase in the global population of this bird over the past few decades (Ueng et al. 2007; National Research Institute of Cultural Heritage 2013).

However, the breeding ecology and requirements, habitat use, and factors that may limit the breeding success of this endangered bird remain unknown. Information on population dynamics is important for an understanding of the ecology of endangered birds (Wei et al. 2005). Moreover, knowledge about population dynamics can help to develop constructive conservation and management plans for endangered species. In particular, data on temporal distribution and breeding status can provide essential basic information that could be of significant importance to conservation efforts (Yeung et al. 2006).

This study describes the current distribution and breeding status of the black-faced spoonbill along the west coast of the Korean Peninsula. Moreover, we suggest a conservation and management plan for this species.

Methods

This study encompasses a literature review on the distribution of black-faced spoonbill in South Korea between 1999 and 2014. For this, we reviewed papers, reports, articles, and books on black-faced spoonbill published since 1999. According to the results of the literature review, an estimated maximum number of individuals was determined at each site (National Research Institute of Cultural Heritage 2007).

The field survey to investigate the breeding status of black-faced spoonbill was conducted between May and July 2013 on offshore islets along the west coast of South Korea. We selected the islets based on the available literature as well as a questionnaire completed by avian ecologists regarding the bird’s breeding sites (Kang et al., 2013). We decided to survey 12 sites (Baekryungdo Island, Kujido Islet, Bido Islet, Seokdo Islet, Youdo Islet, Seomando Islet, Sangyeobawee Islet, Kaksiam Islet, Suhaam Islet, Maedo Islet, Namdong retaining basin, and Hwangseodo Islet) within the Gyeonggi Bay area, Gyeonggi Province and Chilsando Islet in South Jeolla Province, which were known breeding sites of this species (National Research Institute of Cultural Heritage 2013). We visited these breeding sites once or twice during the study period.

In the field survey, the number of nests and individual birds were counted at each breeding site. These counts were used to estimate the population size of the birds on each islet (Hur et al. 2005). We also recorded the characteristics of the nests and surveyed vegetation types and land cover in the breeding areas.

Results and discussion

Black-faced spoonbills were mainly distributed on uninhibited islets off the west coast of the Korean Peninsula. Several stopover sites were distributed on the south and east coasts of South Korea (Figure 1). Most observations of the black-faced spoonbills were recorded in the Gyeonggi Bay area, which contains well-known breeding sites. Many observed sites were stopover sites for this species. Numbers of observed individuals in south and east coast areas were much lower than in the west coast area. Moreover, the birds overwintered on Jeju Island, which is located in the southern part of the Korean Peninsula (Table 1).

Figure 1. Distribution of black-faced spoonbill (Platalea minor) from 1999 to 2014 in South Korea. 1. Gyeonggi Bay area (Baekryungdo Island, Kujido Islet, Bido Islet, Seokdo Islet, Youdo Islet, Seomando Islet, Sangyeobawee Islet, Kaksiam Islet, Suhaam Islet, Maedo Islet, Namdong retaining basin, and Hwangseodo Islet); 2. Yeongjondo Island; 3. Oido Island; 4. Sihwaho Lake; 5. Asan Bay; 6. Daeho Lake; 7. Kanwolho Lake; 8. Keum River estuary; 9. Mangyeong River; 10. Chilsando Islet; 11. Mooan; 12. Jindo Island; 13. Hyungsan River; 14. Suncheon Bay; 15. Gwangyang Bay; 16. Sacheon Bay; 17. Madongho Lake; 18. Upo Wetland; 19. Junam Reservoir; 20. Nakdong River estuary; 21. Gangneung; 22. Cheongchoho Lake; 23. Yongsu Reservoir; 24. Seongsanpo. ■, breeding site; •, stopover; ▴, wintering site.

Table 1. Maximum observed number of black-faced spoonbill (Platalea minor) individuals from 1999 to 2014 in South Korea.

Area	No. of individuals (year)	Site type	Reference	No. from Figure 1
Gyeonggi Bay area*	652 (2006)	Breeding	NRICH 2007	1
Yeongjondo Island	3 (2005)	Stopover	Kim 2006	2
Oido Island	4 (2004)	Stopover	NRICH 2007	3
Sihwaho Lake	40 (2005)	Stopover	NRICH 2007	4
Asan Bay	1 (1999)	Stopover	NRICH 2007	5
Daeho Lake	1 (2001)	Stopover	NRICH 2007	6
Kanwolho Lake	5 (2004)	Stopover	Kim and Kim 2005	7
Keum River estuary	1 (1999)	Stopover	NRICH 2007	8
Mangyeong River	22 (1999)	Stopover	NRICH 2007	9
Chilsando Islet	100 (2014)	Breeding	NRICH 2014	10
Mooan	2 (2004)	Stopover	NRICH 2007	11
Jindo Island	2 (2003)	Stopover	Kim and Kim 2005	12
Hyungsan River	1 (2006)	Stopover	NRICH 2007	13
Suncheon Bay	6 (2004)	Stopover	Kim 2006	14
Gwangyang Bay	1 (2004)	Stopover	Kim 2006	15
Upo Wetland	1 (2001)	Stopover	Kim and Kim 2005	18
Junam Reservoir	1 (2002)	Stopover	Kim and Kim 2005	19
Nakdong River estuary	3 (2004)	Stopover	Kim and Kim 2005	20
Gangneung	4 (2003)	Stopover	Kim and Kim 2005	21
Cheongchoho Lake	1 (2000)	Stopover	Kim and Kim 2005	22
Yongsu Reservoir	6 (2005)	Wintering	NRICH 2007	23
Seongsanpo	24 (2002)	Wintering	NRICH 2007	24

Note: *Gyeonggi Bay area: Baekryungdo Island, Kujido Islet, Bido Islet, Seokdo Islet, Yodo Islet, Seomando Islet, Sangyeobawee Islet, Kaksiam Islet, Suhaam Islet, Maedo Islet, Namdong retaining basin, and Hwangseodo Islet.

We observed 638 black-faced spoonbill nests between April and July 2013 along the west coast of the Korean Peninsula. With the exception of 76 nests that were observed on Chilsando Islet, the other nests were observed in the Gyeonggi Bay area: Kujido Islet, Bido Islet, Namdong retaining basin, Youdo Islet, Suhaam Islet, Seomando Islet, and Maedo Islet, which are the major breeding areas for these birds (Table 2). On the basis of our observations, we estimate that the breeding population of black-faced spoonbills in South Korea is c. 1200. In previous studies, total numbers of breeding nests and breeding sites were less than the results of this study. Numbers of breeding nests increased in Bido, Seomando, and Chilsando islets, and decreased in Seokdo and Youdo islets in this study compared with previous studies (Table 2). There were no records of breeding nests in most of the breeding sites in previous studies. This study has therefore obtained more complete information on breeding nests and sites in South Korea.

Table 2. Observed number of black-faced spoonbill (Platalea minor) breeding nests at major breeding sites in this study (April–July 2013) and in previous studies (1999–2012) in South Korea.

Site	This study	Previous study	References
Baekryungdo Island, Gyeonggi Bay area*	3	-
Kujido Islet, Gyeonggi Bay area	144	-
Bido Islet, Gyeonggi Bay area	104	36	Kim 2006
Yeokdo Islet, Gyeonggi Bay area	-	30	Kim 2006
Seokdo Islet, Gyeonggi Bay area	15	16	Lee et al. 2005
Youdo Islet, Gyeonggi Bay area	60	70	Kim 2006
Seomando Islet, Gyeonggi Bay area	40	1	MLTMA 2009
Sangyeobawee Islet, Gyeonggi Bay area	2	-
Kaksiam Islet, Gyeonggi Bay area	12	-
Suhaam Islet, Gyeonggi Bay area	41	-
Maedo Islet, Gyeonggi Bay area	35	-
Namdong retaining basin, Gyeonggi Bay area	103	-
Hwangseodo Islet, Gyeonggi Bay area	3	-
Chilsando Islet, South Jeolla Province	76	18	NRICH 2011
Total	638	171

Note: *Gyeonggi Bay area: Baekryungdo Island, Kujido Islet, Bido Islet, Seokdo Islet, Yodo Islet, Seomando Islet, Sangyeobawee Islet, Kaksiam Islet, Suhaam Islet, Maedo Islet, Namdong retaining basin, and Hwangseodo Islet.

There are good rocky habitats available on the islets that enable the black-faced spoonbills to breed. Moreover, most of the breeding sites were identified on uninhabited islets, except Baekryungdo Island and Namdong retaining basin. This observation suggests that this species prefers areas with low levels of human disturbance (Chong and Pak 1999; Ueta et al. 2002). It is known that breeding pairs of the bird have increased in South Korea (National Research Institute of Cultural Heritage 2013). However, the factors influencing this increase are not clearly understood. More detailed information on life cycle in this species would be very useful for furthering our understanding of its reproduction and population dynamics (Kim 2006).

Black-faced spoonbills feed by wading in water and sweeping their bill from side to side while moving slowly (del Hoyo et al. 1992; Swennen and Yu 2005). Feeding behavior mostly occurs in water between 6 cm and 21 cm deep. Their preferred feeding sites are gradually sloping or flat, with fine sediment along the bottom and few obstructions (Swennen and Yu 2005). These birds use intertidal flats in sheltered bays and estuaries as feeding habitats (Yu and Swennen 2004). Protection and improvement of feeding sites are essential for the breeding success and conservation of this bird (Liang et al. 2002; Ueng et al. 2006).

Foreshores and wetlands along coastal areas are disappearing each year (Oh et al. 2009). In particular, increasing levels of tourism, coastal developments, and tideland reclamation are major factors that threaten the habitats of the black-faced spoonbill. The conflict between conservation and human disturbance is difficult to resolve, and factors such as visits from photographers and tourists, fishing, and egg collection should be considered (Wei et al. 2005; National Research Institute of Cultural Heritage 2013). Human disturbance, such as tourism, coastal development, tidal reclamation, photographers, and egg collection should be strictly managed by the Korean government (National Research Institute of Cultural Heritage 2014).

Black-faced spoonbills migrate to East Asian countries, which are important areas for conservation of this species. Sites used for breeding, stopover, summering, and wintering by this bird should also be managed (Jin et al. 2008). Moreover, a significant number of breeding islets remain undiscovered in the Demilitarized Zone (DMZ) of the Korean Peninsula (Ueta et al. 2002). Consequently, we recommend that the habitats of black-faced spoonbills should be closely monitored in future.

Conclusion

Small uninhabited islets off the west coast of the Korean Peninsula are important breeding and stopover sites for the black-faced spoonbill. For the successful conservation and management of these birds, it is essential to understand their distribution, breeding status, ecology, and patterns of habitat use. An action plan based on the available ecological information should be prepared for this bird. Moreover, long-term ecological research is important to monitor the population and population dynamics of this critically endangered species.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by the National Research Institute of Cultural Heritage, Cultural Heritage Administration, Republic of Korea [NRICH-1507-B03F-1].