HKBWS Surveyor

A Lesser Cuckoo was heard in the early morning on Sunday.
It was heard at the upper carpark about 700 meters (altitude).
It probably breeds in Hong Kong.

ajohn

According to the Ripley Guide to South Asia (Rasmussen and Anderton) Lesser Cuckoo parasitises Cettia and Phylloscopus warblers.
Of these, the only species potentially breeding in HK is Brownish-flanked Bush Warbler, but the population of these seems small, so I think it is unlikely that Lesser Cuckoo breeds regularly in Hong Kong

lmichael

I think that this is only the second claim of a 'heard' Asian Lesser Cuckoo in Hong Kong so please submit the record formally (only two or three other records). Recording would be great but if not please try to describe the call in words.

Regarding ajohn's comment I wonder if Asian Lesser Cuckoo could also parasitise prinias or tailorbirds: this post inspired me to look at my copy of 'Cuckoos, cowbirds and other cheats' (try it - a great combination of birding and 'science') and (some) cuckoos are not too stereotyped not to opportunistically try new hosts. That said, Tai Mo Shan has been well enough covered in the last half century (personally I did fieldwork there from 1995 - 1998) - I don't think that we have overlooked a regular breeding population!

Mike Leven

ajohn

No doubt Lesser Cuckoo could use alternative hosts. Certainly common cuckoo has been recorded parasitising many different species. Personally I would have thought tailorbirds/prinias were unlikely due to their nest shape (although Plaintive does use these as hosts).  Mountain tailorbird (which is supposedly related to Cettia) may be possible but even so I think it is unlikely that such a rare migrant would successfully manage to find a mate and a suitable alternative host.

I agree with Mike that it is unlikely that a regular breeding population has been overlooked - more likely this is a late migrant that has stopped en route to China.

HKBWS Surveyor

Thanks for both men’s ideas and information.

Based on our survey on Tai Mo Shan upper area, Brownish-flanked Bush Warbler was mostly found at the southern side of Tai Mo Shan. The high density of Brownish-flanked BW area is concentrated in upper part of Tai Shing Stream. In fact, within breeding season, they rely on montane forest and stream and grassland nearby.

For the Lesser Cuckoo that was exactly heard there. The cuckoo was first heard at 0300am and moved around the slope to west side. It finally heard near the upper car park around 0530am. It seems that it moved down to Chuen Lung (the southwest of Tai Mo Shan, also is the slope of Tai Tso stream).

It may breed in Hong Kong. And it possibly found its host on Tai Mo Shan. However, its breeding status is still a question mark. A juvenile and its host can prove their real breeding status in HK.

By the way, the north of Tai Mo Shan (upper part of Ng Tung Chai) is also another area for Brownish-flanked BW. Also, one Russet Bush Warbler was heard at this area on last Saturday. Russet BW is probably established as a local breeder in HK.

George

ddavid

I find this very interesting - just the thought that people are wandering around on Tai Mo Shan in the very early hours of the morning fascinates me!!!

More seriously, you're obviously doing a very detailed survey - and I hope that the results will be made available to us all. You state that the high density of Brownish-flanked Bush Warblers is concentrated in the upper part of Tai Shing Stream. Do you have any details of numbers?? I mean, based on your survey, how many BFBW are actually holding territory on Tai Mo Shan?

It seems to me a possibility that if BFBW is establishing itself as a breeding bird on Tai Mo Shan in significant numbers, then the likelihood of Asian Lesser Cuckoo breeding in HK could (possibly) increase proportionally. (However, I'm fully aware that the term "significant" is open to varied interpretation.)

Anyway, good luck with the survey, and I look forward to the published results.

David