'E's not pinin'!
'E's passed on!
This squirrel is no more!
He has ceased to be!
'E's expired and gone to meet 'is maker!
'E's a stiff!
Bereft of life, 'e rests in peace!
If you hadn't nailed 'im to the perch 'e'd be pushing up the daisies!
'Is metabolic processes are now 'istory!
'E's off the twig!
'E's kicked the bucket, 'e's shuffled off 'is mortal coil, run down the curtain and joined the bleedin' choir invisibile!!
[well, you knew this was coming, sooner or later]....;D