Maybe he's just a goofy snake - could be he picks up on your heat signature before he clues in on the rodent. I have some snakes (different species) that are the same way.

When you're offering the rodent to him, how do you hold it w/the tongs? If you grab it behind the shoulders & get it nice & close to him, it should help him key in on the rodent. Also, how long are your tongs?

K