Black-faced spoonbill

Black-faced spoonbill
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Pelecaniformes
Family: Threskiornithidae
Genus: Platalea
Species: P. minor
Binomial name
Platalea minor
Temminck & Schlegel, 1849

The black-faced spoonbill (Platalea minor) has the most restricted distribution of all spoonbills, and it is the only one regarded as endangered. Spoonbills are large water birds with dorso-ventrally flattened, spatulate bills.[2] These birds use a tactile method of feeding, wading in the water and sweeping their beaks from side-to-side to detect prey.[3] Confined to the coastal areas of eastern Asia, it seems that it was once common throughout its area of distribution. It has a niche existence on only a few small rocky islands off the west coast of North Korea, with four wintering sites at Macau, Hong Kong, Taiwan and Vietnam, as well as other places where they have been observed in migration. Wintering also occurs in Cheju, South Korea, Kyushu and Okinawa, Japan, and the Red River delta in Vietnam. More recently, sightings of black-faced spoonbill birds were noted in Thailand, the Philippines, mainland China, and Macau[4] They were classified as an endangered species through IUCN in 2005.[5] Declines in their population are predicted in the future, mainly due to the amount of deforestation, pollution, and other man-made industries.

The black-faced spoonbill population in the 2012 census was recorded at 2,693 birds, with an estimation of 1,600 mature birds. Breeding colonies occur between March and August, on small islands. These birds are known to be crepuscular eaters, using intertidal mudflats.[4]

Conservation efforts have been made, and surveys were taken in order to determine the opinions and awareness of the local residents, residing close to the black-faced spoonbill’s natural habitats. One survey taken by Jin et al. 2008, inquired upon the ‘Willingness-To-Pay” factor in the locals, as well as understanding effects on mandatory surcharges compared to voluntary payments.[3]

Taxonomy

A study of mitochondrial DNA of the spoonbills found that the black-faced and royal spoonbills were each other's closest relatives.[5] Out of the six Platalea species within the family Threskiornithidae, the black-faced spoonbill is the rarest.[5]

Breeding

Black-faced spoonbills reached a serious low in population in the 1990s, but by 2003 their numbers increased to at least 1,069 counted individuals.[5] While it is known that their breeding area covers northeastern China and several islands between North and South Korea,[6] human-assisted breeding efforts have not been overly successful due to the difficulty in sexing the black-faced spoonbills, yet using the polymerase chain reaction technique on DNA samples has allowed researchers to use another method to correctly sex adult Platalea minor specimens.[5]

After migrating to their wintering locations, black-faced spoonbills return with yellow breeding plumage, which extends from the back of their heads to their breasts.[6] While this plumage only develops during the third or fourth year of life when the black-billed spoonbill is sexually mature, only about half of black-billed spoonbills with this plumage breed each breeding season, which contributes to the very slow pace at which the population numbers are increasing.[6]

Distribution

The global population of this species, lily based on the winter population count carried out in 1988-1990 in all known sites, was estimated at 288 individuals. As of 2006, thanks to conservation efforts over the years, the estimated global population had increased to 1,679 ; the 2008 census resulted in an estimated total count of 2,065 individuals ; and a 2010 census reported 2,346 . The niche population of North Korea does not exceed 30 birds, which implies that there must be another colony which has not been discovered yet, and which is perhaps located in northeast China; for example, on the islands of Liaoning (near the Korean nesting zone).

The model at right shows that the founder effect speciation was more likely for the divergence of the Pl. regia species and the Pl. minor, black-faced spoonbill, species. Founder effect speciation occurs when a population arises from a small set number of individuals, known as the founders. This type of speciation adds significance to the importance of selection even though there is a vast diversity of birds. The speciation process and demography at the time also contribute together in the birds’ evolutionary changes in behavior such as migration routes and habitat locations.[7]

Black-faced spoonbills are migratory birds so their conservation is based on the protection of their breeding, “stop-over” and wintering grounds.[8] Thus, their conservation comes with a lot of conditions. However, spoonbills are able to adapt to disturbances of large-scale. Their distribution remains unclear.[8] However, through models, maps a-h, black-faced spoonbills’ wintering distributions were able to be recorded. From these models, the spoonbills’ future distributions were predicted under possible climate changes conditions.[8]

Threats

It is thought that the principal cause of the decline of this species is the destruction of its habitat, more particularly the "valorization" of intertidal mudholes for agriculture, and more recently aquiculture and industrialization. The Korean War (1950–1953) must also have had a negative impact on the species, because the birds ceased nesting in South Korea at that time. In Japan, where it was once common for them to winter, they became extremely rare at this same time, and in later years there has never been a winter in which more than 5 birds were observed.

With the construction of the Shinkansen Bridge in the Yatsushiro Sea between 2004 and 2009 next to a very important migration site for the black-faced spoonbills, many feared that it would cause their numbers to decrease. Thankfully, because of carefully planned out measures implemented in order to counter act the construction of the bridge, the population actually managed to increase during the time of construction.[9]

Human disturbances can also be much more direct. Many humans disturb mating patterns unknowingly by taking photographs of birds during their mating time, leading to a decrease in offspring. Other humans willingly take eggs for selfish reasons, which accounted for 10% of the eggs taken in the Xing-Ren Tuo region of China in 1999.[10]

Conservation

The bird is a protected species in China as part of the China Red Data Book; its stopover site at Jiuduansha off Shanghai is a national nature preserve.[11] In Hong Kong, it is a protected species under Wild Animals Protection Ordinance Cap 200. In Mai Po Marshes, a quarter of the world's population of black-faced spoonbill can be found during migration.

The species is reasonably well protected in North Korea, where their nesting islands off the coast were declared a Zone of Protection with restricted access. There remain nevertheless several threats, mainly in the wintering zones. The need for land to assign to industry is great in the wintering sites in Taiwan, whereas those in Vietnam are being converted for shrimp breeding, though they are within a reserve subject to the Ramsar Convention.

During the winter months, over half of the black-faced spoonbill population migrates to the Chiku Wetland in southwestern Taiwan. The birds incapable of catching large fish; therefore many of them rely on the largescale mullets to feed off of in the winter months spent in the wetlands.[12] These mullets however have recently become endangered due to the increase of spoonbill population who spend the winter months there (minimum of 191 birds in 1991/1992 up to a minimum of 840 in 2004/2005). Conservation of the largescale mullet is imperative in order to continue to sustain the endangered black-faced spoonbills.[12]

In Hong Kong, disturbances by fishermen and shell gatherers often prevent the birds from feeding at low tide. In addition, with the continued expansion of human populations in the Far East, pollution will probably become an important problem. Disease has the ability to devastate the black-face spoonbills as well. In the winter of 2002/2003, 73 of the population died due to avian botulism. It may be necessary to establish additional protective areas or reserves in order to not let the population of birds to succumb to disease.[13]

The black-faced spoonbill is legally recognized as natural monument #205 in South Korea.

References

  1. ↑ BirdLife International (2012). "Platalea minor". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
  2. ↑ Swennen, C., & Yu, Y. (2005). Food and Feeding Behavior of the Black-faced Spoonbill. Waterbirds, 28(1), 19-27.
  3. ↑ 3.0 3.1 Jianjun Jin, Zhishi Wang, Xuemin Liu, Valuing Black-faced Spoonbill Conservation in Macao: A Policy and Contingent Valuation Study, Ecological Economics, Volume 68, Issues 1–2, 1 December 2008, Pages 328-335, ISSN 0921-8009.
  4. ↑ 4.0 4.1 BirdLife International 2012. Platalea minor. In: IUCN 2012. IUCN Red List of Threatened Species.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 Chesser, R.Terry; Yeung, Carol K.L.; Yao, Cheng-Te; Tians, Xiu-Hua; Li Shou-Hsien (2010). "Molecular Phylogeny of the Spoonbills (Aves: Threskiornithidae) based on mitochondrial DNA". Zootaxa (2603): 53–60. ISSN 1175-5326
  6. ↑ 6.0 6.1 6.2 Black-faced Spoonbill Conservation Association. (2001).Black-faced Spoonbill. Retrieved from http://www.bfsa.org.tw/en/ep02.htm
  7. ↑ Yeung, C. K. L., Tsai, P. (n.d.) (2010). Testing Founder Effect Speciation: Divergence Population Genetics of the Spoonbills Platalea regia and Pl. minor. MBE, 28(1), 473-482 .
  8. ↑ 8.0 8.1 8.2 Hu, Junhua, Hu, Huijian, Jiang, Zhigang (2010). The Impacts of Climate Change on the Wintering Distribution of an Endangered Migratory Bird. Oecologia 164: 555-565.
  9. ↑ Takano, S., & Henmi, Y. (2012). The Influence of Constructing a Shinkansen Bridge on Black-faced Spoonbills Platalea minor Wintering in Kyushu, Japan. Ornithological Science, 11(1), 21-28.
  10. ↑ Guo-An, W., Fu-Min (n.d.) , (2005). Nesting and Disturbance of the Black-faced Spoonbill in Liaoning Province, China. Waterbirds, 28(4), 420-425.
  11. ↑ "Birds". The Shanghai Jiuduansha Wetland Nature Reserve (Shanghai), 2014.
  12. ↑ 12.0 12.1 Ueng, Y., (n.d.), (2007). Diet of the Black-faced Spoonbill Wintering at Chiku Wetland in Southwestern Taiwan. Waterbirds, 30(1), 86-91.
  13. ↑ Ueng, Y., Wang, J., & Hou, P. L. (2007). Predicting Population Trends of the Black-faced Spoonbill (Platalea minor). The Wilson Journal of Ornithology, 119(2).

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