Unusual night sound

[CeeJay]

At about 10.00pm each night for the last few nights we have heard a noise coming from a very large pine tree at the rear of our house which is a low beep with a few seconds gap and repeated and continues for about an hour. I think it may be some sort of nocturnal bird although my wife seems to think it could be the local frog contingent getting frisky and not coming from the tree but from the nearby river Herault.

Any thoughts?

[Russethouse]

Could it be this ? There is a sound file attached so you should be able to tell.

http://www.planetepassion.eu/AMPHIBIANS-IN-FRANCE/Midwife-toad-France.html

[Grumpy]

Check to see if you are hering it from up the tree or at ground level.  We have a Midwife Toad (I don't know if they climb trees but I doubt it) that makes a regular beep rather like an electronic noise indicating a flat battery.  When you approach it it stops till it gets its confidence back then starts again.  Its a small drab toad equivalent to a 2 year old common toad and very hard to find. They like damp places with holes they can hide in.  Occasionally we've had 2 or 3 each beeping on a slightly different none.

Grumpy