pseudk

Sorry for the bad quality
It was taken at Mai Po around 6pm on 6/1/09

lpaul

This is a Savannah Nightjar

pseudk

Thanks Paul
But from what feature can we identify the Nightjar inflight??

lpaul

Do you mean to family level, species level or both?!

pseudk

For Savannah Nightjar.

John Holmes

I have to say that I do not think this is a Savanna Nightjar. Savanna Nightjar has squarer-looking wings, with a bulge on the trailing edge. Even a female should show a buff patch across the primaries, and the wings would be more heavily barred, and held in a distinct "V" shape.  

I think this is a Kestrel. No dark tip to tail is visible, but this bird is slender and finely barred, gliding on flat wings. The head looks odd but maybe it was twisted in a strange position. (Do you have any more photos of this individual ?)

But with a shot like this, perhaps five different commenters will have five different opinions !

John

pseudk

Thanks John

I dont have another better shot as the bird just appeared for few seconds.
I have post the photo to HKwildlife too, and some of the birders also agree that it was a Kestrel.
I the first impression of mine to this individual also fell into Kestrel but I was not sure as the environment there was quite dark.

深藍-Owen

add some Savannah Nightjar flight shot for compare..