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First record of European Beak (Libythea celtis) in Hong Kong
Important finding by Butterfly Surveyor at Sha Tau Kok (19 Jan 2015)


A new record of European Beak (Libythea celtis), belonging to the family Libytheidae, at Sha Tau Kok is the also the first record of this species in Hong Kong. There are only three Libytheidae species in China. In addition to European Beak, one other member of the Libytheidae has been recorded in Hong Kong, so two of the three species have been found in the SAR. It is believed that the new species may become resident in Hong Kong.

The new species was found at 1pm on 9 January 2015, in woodland near Sheung Tam Shui Hang, on the Sha Tau Kok survey route of Green Power's Butterfly Surveyors scheme. Hui Chun Tung, a butterfly surveyor, made the first sighting and photographic record. He recalled that at first sight he thought it was an uncommon Lycaenidae, but considered it appeared quite different. After some efforts he confirmed it to be a new record of European Beak, and took the first and only photographic record in Hong Kong.

There are over 260 species in 11 families of butterflies in Hong Kong. With the new addition, there are now two members of the Libytheidae family. The original member is Club Beak (Libythea myrrha), discovered in July 2011 in Hong Kong Wetland Park. Members of the Libytheidae family have long thick labial palps – twice the length of the head, growing at the labium, so are commonly called "snout butterflies".

European Beak is a small butterfly with wingspan of only 5 cm. Its wings are dark brown with orange red patterns on the forewings and hindwings. On the forewings there are a hook at the tip and three white spots. The butterflies are fast flying. The adults feed on tree sap and liquid humus, while the caterpillars prefer leaves of Chinese Hackberry (Celtis sinensis).

According to literature, European Beak is distributed widely, including many provinces in mainland China, Taiwan, Japan, India, Thailand and as far away as southern Europe. However, there were no previous records in Hong Kong. One special feature of the species is that unlike most butterflies which overwinter in the form of eggs, caterpillars or pupae, European Beak is among the few that can overwinter as adults.

Designate area adjoining Robin's Nest as conservation area

Sha Tau Kok had been closed for 60 years since the 1950s, as a restricted frontier area. Before it was re-opened in February 2012, little is known about local butterflies. Green Power carried out the first butterfly survey there in 2012, and thereafter included Sha Tau Kok in the Butterfly Surveyor Scheme, to fill in an empty space in Hong Kong's ecological database.

Over the past three years, Green Power recorded 148 species of butterflies at Sha Tau Kok, which is about 55% of the Hong Kong total. These include 12 very rare and 15 rare species. There have been important findings at the site too; for example, in 2013 the butterfly surveyors found Hooked Oak Blue (Arhopala paramuta), which had not been sighted in Hong Kong for over 30 years. The discovery of European Beak is further proof that Sha Tau Kok has high butterfly diversity.

Despite the confirmed rich natural resources in Sha Tau Kok, the area is unfortunately, undergoing very rapid development since the opening up of the frontier area. The immense pressure on natural habitats by development of varying scales is alarming. Sha Tau Kok is close to Fanling new town, and most villages are connected by Sha Tau Kok Road. The Northeast New Territories Development Plan also acts as catalyst for all kinds of development in Sha Tau Kok. Since February 2012, numerous leisure farms, war game fields and car parks have been set up, and small houses as well as large scale village housing estates also mushroomed. Under the existing outline zoning plan, there are only 3 hectares of land designated as "conservation area", which can hardly protect most natural sites. By contrast, over 39 hectares of land belong to "rural development area" and 7.38 hectares belong to "recreation area", indicating that land development activities and population will continue to increase.

The government must prioritise protection of Sha Tau Kok with its high ecological and special scientific value, to avoid foreseeable damage. The woodland next to Robin's Nest is home to many rare butterflies. Green Power urges the government to designate the land as conservation area or Site of Special Scientific Interest (SSSI). Apart from butterfly conservation, the area can act as a buffer zone between Sha Tau Kok villages and the potential Robin's Nest Country Park.

Butterfly Surveyors is part of Shell Nature Watch - Butterfly Explorer scheme that was launched in 2008. This is the first butterfly survey team formed by ordinary citizens and is a strong and long term human resource for collecting local butterfly data. To date there are 166 qualified butterfly surveyors covering 9 survey sites: San Tau of Tung Chung, Luk Keng of Fanling, Wu Kau Tan, Lam Tsuen (She Shan and Ng Tung Chai) and Yuen Tun Ha of Tai Po, Shum Chung and Yung Shu O of Sai Kung, Sha Tau Kok, Pak Sha O and Lai Chi Kok of Sai Kung, and the newly added Mui Wo of Lantau from last year.

Image
© Hui Chun Tung
European Beak(Libythea celtis
Image
© Hui Chun Tung
European Beak(Libythea celtis

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