Whats Been Stripping My Leaves?

Just a thought.....
These caterpillars that have been stripping my Geranium leaves (I dont know what they are).
Why are the birds not eating them?is it because we are feeding wild birds too much and they no longer need to forage,they dont know what they are missing...big fat juicy caterpillars. :confused:

 

Didn't know anything ate Geranium leaves.
Looks like some kind of hawk moth larva.

 

Have had the same problem a couple of times but it seems to have moved counties. No idea what it is - sorry.

 

My geraniums are the same with fine lacy leaves. Thankfully, didn't see any of those 'orrible little things, but serious question with mention of the moth larva. I love my evening primroses but know they attract moths. Is it possible having the EPs makes my garden more likely to suffer?