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        Discussion Area 討論區 >> Bird Identification 鳥類辨識 >>  長腳鷸亞種 Black-winged Stilts subspecies
        
(Message started by: cywong on Jul 19^th, 2005, 10:59pm)

Title: 長腳鷸亞種 Black-winged Stilts subspecies
Post by cywong on Jul 19^th, 2005, 10:59pm

Mai Po 29/05/2005
http://img.photobucket.com/albums/v191/cywong/5b6ca540.jpg
It seems that there are 3 types of Black-winged Stilts in Hong Kong.
The one inside the blue circle has a white crown and white hindneck (himantopus?);
the one inside the pink circle has a white crown and black hindneck(leucocephalus)?;
the one inside the red circle has a black crown and black hindneck(???).
Would experienced birdwatchers please give expert opinion?

Title: Re: 3 types of Black-winged Stilts in Hong Kong?
Post by Michael_Leven on Jul 22^nd, 2005, 4:55pm

A very educational photo. The problem with Black-winged Stilts in Hong Kong is that the amount of black on the head and neck is very variable - seasonally, between males and females and just individual variation.

If I had to put a name to them I would call both the pink and red circled birds himantopus types and the blue one a leucocephalus type. However I am not convinced that they are really different (sub)species.

According to the literature HK is close to the boundary between these two forms (with leucocephalus to the south). I was recently birding in Jilin Province and, on average, birds there had more black on the head and neck than HK birds - however, again there was a lot of variation.

Overall I think that the variation in Hong Kong birds suggests that we are in an intergrade zone between the two subspecies, furthermore that the case for treating the two forms as separate species (e.g. in Howard & Moore) is weak.

Any other opinions?

Mike Leven

Title: Re: 3 types of Black-winged Stilts in Hong Kong?
Post by cywong on Jul 27^th, 2005, 10:50pm

Thanks for Mr. Leven's expert opinion.

Title: Re: 3 types of Black-winged Stilts in Hong Kong?
Post by Captain on Jul 28^th, 2005, 9:12am

Is it a permanent individual variation? Or simply a variation of an individual (population) with time.

Perhaps we could observe the pattern variation of marked individuals. See whether the pattern change over time.

If it is permanent, perhaps it could serve as ID of individual B-w Stilt.

Captain