Board logo

Subject: dark-sided vs grey streaked flycatcher [Print This Page]
Author: sgeoff    Time: 7/10/2015 11:37     Subject: dark-sided vs grey streaked flycatcher

Is there an easy way to tell if this is a grey-streaked or a dark-sided flycatcher?  Lamma cable road October 7th 2015


[ Last edited by sgeoff at 7/10/2015 11:38 ]

Image Attachment: dsf1.jpg (7/10/2015 11:37, 75.73 KB) / Download count 521
http://hkbws.org.hk/BBS/attachment.php?aid=23178

Author: irsychan    Time: 8/10/2015 08:41

On first glance, it looks like dark-sided.  But after adjusting the exposure of the photo, it looks like an immature grey-streaked.
Interesting.  Would like to hear from the experts.

[ Last edited by irsychan at 8/10/2015 08:43 ]
Author: ajohn    Time: 8/10/2015 15:18

It looks like a juvenile Dark-sided to me.
- The underparts appear to be mottled with dark, rather than showing defined streaks
- The bill looks relatively short, and mostly dark
- The eye-ring broadens behind the eye
- White spots on the upperparts are remaining juvenile plumage. Dark-sided are most often seen in Hong Kong as juveniles, whereas juvenile Grey-streaked seems to be less common (most presumably moult before migrating).

Compare these two juvenile/first winter birds:
Dark-sided: http://orientalbirdimages.org/se ... ize=1&Location=
Grey-streaked: http://orientalbirdimages.org/se ... ize=1&Location=

For me, Grey-streaked usually looks somehow larger and more powerful compared to similar flycatchers, whereas Dark-sided somehow seems a little smaller and more delicate.
Author: sgeoff    Time: 8/10/2015 17:01

That was my feeling for similar reasons but I don't have experience of this species so it's nice to have some confirmation from others who have more knowledge of the species in question.  Many thanks.
Author: irsychan    Time: 8/10/2015 17:49

Quote:
Original posted by ajohn at 8/10/2015 15:18
It looks like a juvenile Dark-sided to me.
- The underparts appear to be mottled with dark, rather than showing defined streaks
- The bill looks relatively short, and mostly dark
- The eye-ring broad ...
I agree with your excellent assessment that this is a first-winter Dark-sided flycatcher.  I just found a paper entitled "Brown, Siberian and Grey-streaked Flycatchers: identification and ageing" by Paul J. Leader (British Birds 103. November 2010), which gives detailed discussion on the differences between Asian Brown, Dark-sided and Grey-streaked, covering both adults and juveniles.  The section on 'Wing shape and primary projection' and Fig. 2 are particularly helpful in further supporting that this is Dark-sided.
Author: sgeoff    Time: 12/10/2015 13:33

Thanks for the reference - it's also free to download, so that's a great resource.



Welcome to HKBWS Forum 香港觀鳥會討論區 (http://hkbws.org.hk/BBS/) Powered by Discuz! 6.0.0