Released birds? The closest location to HK is Dinghushan (central Guangdong; correct me if I am wrong). Author: cywong Time: 11/01/2011 22:43
Thanks all for the kind feedback.
I think I should leave wcaptain's question for bird experts.Author: lmichael Time: 12/01/2011 16:50
Very likely released birds; laughingthrushes are not migratory and this is a forest species. Most tellingly, note that in pictures 3 and 4, 1/3 of the tail on one side is growing suggesting cage damage.
However, it is a south China species and could colonise from realeased birds as a number of other babblers and laughingthrushes have in Hong Kong.
Mike Leven Author: wcaptain Time: 12/01/2011 17:44
Hi Mike,
so, do you think it can naturally colonize in HK?
Captain Author: lmichael Time: 28/01/2011 14:01
Hi Captain
Sorry, just noticed your question.
I don't see you it should not colonise, in principle. The three key requirements for successful establishment of an introduced species are habitat suitability, empty or at least not filled, ecological niche and sufficient numbers and genetic diversity in the founder population. In my experience in South China it occupies a similar niche to Greater-necklaced and they are often in mixed flocks which suggests that (a) habitat that it suitable for Greater may be suitable for Lesser and (b) it isn't excluded by Greater. Also, our forests still have many fewer breeding species than Guangdong forests so there are still likely to be partially vacant niches. The big issue is likely the size of the founder population: if it is very small it could just fail for stochastic reasons and/or inadequate genetic diversity.
Cheers
Mike Author: wcaptain Time: 28/01/2011 14:59
Mike,
Thanks. My concern is whether they can colonize in HK by themselves without interference of people.
Greater Necklaced Laughing Thrush is supposed to be the decendents of release birds. I suppose it is very difficult for birds of low flying ability like laughing thrush colonizing HK. It is hard to image they can penetrate the concrete forest of Shenzhen.
Cheers,
Captain Author: lmichael Time: 31/01/2011 14:30
Captain
I think natural colonisation is most unlikely. As you say, forest laughingthrushes have low dispersive ability. Greater Necklaced in Hong Kong are considered to be descendents of released birds, but it is one of the less clear cut cases as it has been recorded in Shenzhen (though of course we don't know about the origin of the Shenzhen birds) and it is relatively widespread and common in Guangdong. However, Lesser Necklaced appears to be much less common in Guangdong and typically just one or two birds are seen compared to flocks of 20-40 Greater Necklaced, so the chances of making it here unaided are probably considerably less than for Greater Necklaced.
Mike Author: cgeoff Time: 31/01/2011 16:33
Although I don't particularly think it's relevant in this case, please remember that the border with Guangdong is not entirely urbanised. The Robin's Nest area is linked to Wutongshan, and it would certainly be possible for birds of low dispersive ability to cross in that area. One of the aims of the proposed Country Park at Robin's Nest is to preserve this linkage and maintain the genetic diversity of wildlife in HK.
Of course, birds at Wutongshan could have come from bird markets in Shenzhen!
GeoffC Author: wcaptain Time: 1/02/2011 10:00
Thanks Geoff and Mike.
I know from some websites in Chinese that religious wildlife/captive animal releases (food fish etc) are regularly organized by groups in Shenzhen and many parts of Guangdong.
The Chinese alliance of animal release (translation) http://www.zhfs.org/
e.g. one bird release activity was organized at Futian, SZ on 26 Dec 2010
深圳福田区梅林慈悲放生小组12月26日（星期日）放生通知
Lesser Necklaced Laughingthrush is fairly widespread in Guangdong, with records in the north of the province and along the West River and East River, including near Guangzhou and at Nan Kun Shan (c 150 km N of HK). The peak count is 40 at Nan Kun Shan. It is not as vocal as Greater Necklaced and hence is easily overlooked. So, while it is not as common or widespread as Greater Necklaced, it is far from being a rare species in Guangdong.
Looking at a relief map of Guangdong, the southernmost range of hills which reach the edge of the Pearl River Delta is the Lianhua Shan, with a highest elevation of 1336 metres only about 70 km northeast of Sha Tau Kok. The hills then continue as the Hai'an Shan to extend east to Daya Bay, with a further outcrops on the edge of Mirs Bay. To my knowledge, except for Wutong Shan in Shenzhen, these hills have not been surveyed for birds. They certainly seem to be a potential route by which normally sedentary species in east Guangdong might reach the New Territories.
Given the above, I would not rule out the possibility that both Greater and Lesser Necklaced Laughingthrushes could reach HK unaided.
Richard Author: lmichael Time: 1/02/2011 14:22
Thank you Richard for the update on Guangdong status of Lesser Necklaced. However, one of the problems with assigning an arrival route is that colonisation could go either way. For example, the feral population of Collared Dove in Hong Kong appears to be increasing and in the last year it has become common at Lok Ma Chau, only about 200m from Shenzhen - I fully expect it to colonise Guangdong from Hong Kong in the nexst few years. Similarily, while it is not improbable that Greater Necklaced Laughingthrush have reach Hong Kong from Wutong Shan, it is equally possible for it to have reached Wutong Shan from Hong Kong (it is now quite common in NE New Territories). It would be interesting to know if it is present in other hills to the northeast but, as Richard says, we don't know much about the bird communities in the hills to the NE of Sha Tau Kok - a very worthwhile project for someone with the time to explore...
Mike
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