Assuming we are talking about the feathered variety. We met a British couple in Pattaya last October who were avid bird watchers (not twichers... apparently there is a difference)
They had a book of Thai birds which kept them happy during their stay, however, they didn't mention any day trips.
I'm sorry I can't help but if you google, you may come up with a good day trip.
Happy Googling
Cheers Geri