lky

I find it difficult to differentiate Great Coucal and Lesser Coucal.  Would you please kindly help?  Thank you very much!
Date:  24 June 2012
Location:  Ping Che, Fanling

Beetle

It looks like a Lesser Coucal to me, based on the light streakings on the breast and overall structure.
Some more ideas from others appreciated!

[ Last edited by Beetle at 24/06/2012 22:21 ]

lky

Thank you very much, Beetle!

It'd be lovely if somebody can kindly tell me the way to identify Lesser Coucal in the field.  It's difficult to see the white streaks in the field.  Is there any other ways to differentiate it with Great Coucal?

Here are 2 more photos of another coucal.  Please advise if it's Lesser Coucal or Great Coucal.  Thank you thank you!

Beetle

For me, size is the most useful feature in field.

HFCheung

I think Iris colour is the best feather.  Lesser Coucal has black iris, Greater has red iris.

HF Cheung

ajohn

I think the best features in the field are probably (not necessarily in  order!):
1. Voice. But in most cases you do not hear them call.
2. Habitat. Lesser is unusual away from grassland or hillside habitats, Greater tends to prefer areas with some shrubs.
3. Size.
4. Mantle/wing colour. Lesser tends to be slightly paler/greyer in tone than Greater, which is usually very strongly rufous-chestnut.
5. Pale streaking on mantle/breast. Can be clearly visible sometimes on Lesser (see second photo of those posted here).
I've never really used iris colour in the field - partly because I forget there is a difference, but also because Lesser is rarely seen well enough  or for long enough to check the iris colour.

Lesser has a very distinctive winter plumage (pale, streaked), which cannot be confused with Greater, but seems to be even shyer and harder to see in winter!

The birds here are Lessers. Ping Che is a very good site for this species.

lky

Thank you very much, Dr. Cheung & Ajohn!

The iris colour of Lesser Coucal is painted in red in "The Birds of HK & S China".  It's mistaken then.

Sorry I have 2 more questions.  According to "The Birds of HK & S China",

1.  The underwing coverts of the Great Coucal in flight is drawn black / dark in colour, but all brown for Little Coucal.  Is it true?  

2.  The lower back of Little Coucal is brown in colour while that of the Great Coucal is black.  Is it true?

ajohn

I think the difference in underwing coverts is true, but it's not really useful in the field (I have looked before, but the underwing coverts of coucals are usually not visible, at least not for long enough to confirm whether they are black or just in shadow!)
There may be a difference in the exact extent of brown/black on the back but again, it may be something that's difficult to judge in the field.

HFCheung

The feature of iris colour is never mentioned in any field guide, as far as I know.  It is a latest invention by some clever birdwatcher.  I think I heard about it from Kwokjai.

[ Last edited by HFCheung at 26/06/2012 21:50 ]

lky

Many thanks, Beetle, Dr. Cheung, AJohn & Kwok Jai!  I've learnt a lot from you.  Thank you thank you!

lky

Sorry I have a problem. On p.399 of the Photo Guide published by HKBWS, the coucals in photos no.4 & 6 have red iris.  Why?

brendank

I think the wing color and head gloss on those photos matches Greater Coucal. Perhaps these were misidentified.

HFCheung

In the initial edition, mistakes in the ID of Coucal were made.  I take full responsibility for that.  At that time I found it difficult to judge the size from the photo.  It was around that time that I realized iris colour as a field mark is the most useful for photos.  Several photos were replaced in the later edition.

HF Cheung

[ Last edited by HFCheung at 3/07/2012 11:32 ]