Out of interest what are people's views on counting birds that you've heard and not seen.
Would it be acceptable on a Life \ Year \ Local patch list?
I know birds heard count in a bird race.
Birds such as Quail, Corncrake and Nightingale are usually difficult to actually see but often heard.
I know lists are a personal and individual records but I would be interested to hear other people's view point on the subject.
If I can positively id the bird from the sound then it is a tick, if not sure then it's not. For a lot of birds that's the best you can do, I've heard more bitterns than I've seen, same with cuckoos.
I never do.