Hi,
There are a couple fo possibilities really.
It could be too cold for him to zero in on, in which case the hairdrier trick mentioned above should work.
Or he might not want to eat for security or other reasons - in which case he is telling you, in the only way he can, to get that thing out of his face.
When he strikes at it does he have his mouth open or closed?
Has he eaten for you before and how long have you had him?
dr del