Den nya bebyggelsen i Finntorp börjar att ta form. Skräddarmästare Engbloms villa väster om Nacka kyrka - på Värmdövägen 113 - vilken ses längst upp till höger i bild, är i färd med att rivas. Foto 1965. gencontrast between pale grey upperwing and blackish outer primaries. Similar spp. Great Crested Tern S. bergii is larger, lacks prominent black tip to bill and has darker grey upperside. Rapportera ett kartfelAnvändarvillkorKartdata Kartdata Distribution and population Sterna bernsteini is a poorly-known species, recorded breeding recently at only two sites on the eastern coast of China: Zhejiang and Fujian Provinces and, outside the breeding season, in Indonesia, Sarawak, Malaysia, Taiwan (China), Thailand and the Philippines (BirdLife International 2001). In June-July 1937, a total of 21 specimens were collected on islets off the coast of Shandong, where it was presumably breeding, indicating that it was locally not uncommon in the past. however, surveys conducted in June-July 2006 suggest that the regional breeding population has been extirpated from the coast of southern Shandong (Chen Shuihua et al. 2009, Liu Yang et al. 2009). Until the rediscovery of the breeding sites on Matsu Islands, Fujian and Jiushan Islands, Zhejiang, the only records were from China, in Hebei in 1978 and Shandong in 1991, with a possible record from peninsular Thailand in 1980. In summer 2000 four adults and four chicks were found amongst a tern colony in the Matsu Archipelago off the east coast of mainland China (but administered by Taiwan). Breeding again took place in 2003, and in 2006 5-7 birds, including a pair of adults and a juvenile, were present (Candido 2006), with a total of 20, including three chicks, reported in 2008 (Hansbro in litt. 2008). In 2010 there were 15 adults and three nestlings at Matsu. there were six adults in 2011 and only four adults (with no successful breeding) in 2012 (S. Chan in litt. 2013). A small group was also found breeding at Jiushan off the Zhejiang coast in 2004 (Kejia et al. 2004), but none bred there in 2005 or 2006. four pairs were recorded in 2007 but all eggs were collected by local people (Chen Shuihua 2007). Two pairs raised two young in 2008, but there was no breeding at Juishan from 2009-2012 (S. Chan in litt. 2013). However, a small group, considered to be a former breeding group of the Jiushan birds, were found breeding at the Zhoushan Wuzhishan Archipelago nature reserve in 2008 (Shuihua Chen 2008, Chen Shuihua et al. 2010), with a maximum of 12 adults and three nestlings there in 2011 and eight adults and four nestlings in 2012 (S. Chan in litt. 2013). In 2013 Tiedun Dao islet in the Jiushan Islands was restored as a seabird colony (BirdLife International 2013). Vegetation was cleared, 300 tern decoys were placed on the island and solar-powered playback systems were used to play contact calls of Great and Chinese Crested Terns. By late July 19 adult Chinese Crested Terns (the largest count since rediscovery) and 2,600 Great Crested Terns were present, and by September at least one juvenile Chinese Crested Tern had successfully fledged. Surveys of the coasts of Shandong and Zhejiang in 2003-2007 suggested that the breeding colonies on the Matsu and Jiushan Islands were the only ones still extant (Chen Shuishua et al. 2009). One to 11 birds (thought to be birds from the Matsu colony) are present from April to September at the Min Jiang estuary, Fujian. Since 2008, a small number of putative hybrid S. bernsteini x S. bergii have also been recorded and photographed at Min Jiang estuary (Chen Lin and He Fenqi 2011), with two recorded at the Matsu Archipelago in June 2011 (Wang Jianhua and He Fenqi in press). The species's movements and wintering grounds remain poorly understood, but heightened awareness in Taiwan (China) has resulted in several records of 1-2 birds using the Pachang River outside the breeding season since 1998 (P. Kennerley in litt. 2003), and more recently in 2004 at Chongming Dongtan National Nature Reserve, Shanghai (Kejia et al. 2004), and the Xisha Archipelago, indicating that it may winter around islands in the South China Sea. An individual was recorded on Palau Lusaolate, north Seram, Indonesia in December 2010 (C. Robson in litt. 2010, Robson 2011). It is thought that the species's known population can be divided into three small flocks: the Taiwan Straits flock, Zhoushan Archipelago flock and northern Chinese coast flock (Jiang Hangdong et al. 2010).In addition, a record of three birds at Rizhao, southern Shandong, in September 2011 adds support to the theory that another flock still exists along the coast of northern China (Qin Yupin and He Fenqi 2011), although these may be post-breeding stragglers from a known colony (Liu Yang in litt. 2012). There is also a very northern record from Tangu, Tianjin, in September 2008 (per Liu Yang in litt. 2012). The total current population is unknown, but is presumably tiny given the paucity of recent records. Population justification The number of breeding adults varies each year, ranging from 12 in 2012 to 26 in 2004. Given this the total number of mature individuals is likely to number fewer than 50, and perhaps most likely 30-49 (S. Chan in litt. 2013). Trend justification Repeat surveys at the two known breeding sites since 2003 have shown an overall decrease in the number of breeding pairs. Ecology Records indicate that it is exclusively coastal and pelagic in distribution. In China (including Taiwan), it has been found on offshore islets (breeding) and tidal mudflats. Threats Many coastal wetlands in its presumed breeding range in eastern China are affected by large-scale development projects and, in China, seabirds are exploited for food. The apparent extirpation of the population that formerly bred along the coast of southern Shandong is thought to be linked to the colonisation and development of its breeding islands since the 1950s (Liu Yang et al. 2009). Breeding failures in 1999, 2001, 2002, 2003 and 2005 at the Matsu tern colonies, and in 2007
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