Well, I don't know. That Nightjar sang continuously for just short of 2 minutes, and of course I didn't include the whole thing. Here's a link to a stereo sample, the same I took the clip from, that's been cut down to about 1 minute. In this longer clip I've cut out the 15 seconds it took me to locate him with the dish and some of the middle so that I could include the echo at the end when the bird suddenly stopped. The clip is 1.2 Mb.
http://www.godsownclay.com/Natural_H.../Nightjar2.mp3
The bird was 40-50 yards away and recorded with a dish.
As to the Barn Owl clips, I really don't see how one could get anything more similar.
romillyh