Spider instead of...

For a few evenings now we hear a squeeking sound coming from our and our neighbours backyard.
We don't have the faintest idea what kind of species produces this sound.
A pygmy owl? a kind of bat?
So I took the camera, set the flash at highest output and tried to shhot at the tree where I thought the cry was coming from.
Nothing could be seen....
And: the sound went on....
The only thing I could do was pointing the camera at a spider in his web...