lmichael

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

lmichael

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

lmichael

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

lmichael

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