Do you think these are from birds or small mammals (rat, maarten, fox)?

I only had one like that this year (and a couple with just a couple nips), and shortly after that, I caught a squirrel. I haven't had any more damaged tomatoes, or squirrels in the trap, so I think that's what it was here. I have a trap out there for them 24/7, and early in the season I get a lot, then they seem to wise up.

I'll try to set up one too... Thanks..

Looks like rodent damage to me.

I would guess squirrel or rat. The squirrels that took interest in tomatoes here did take bites off the bush and left it half gnawed like that. They've done the same thing with zucchini too. The year we had rats though, they would take the whole tomato as soon as it was ripe, back to the burrow to devour at will. It took a while to figure out that the tomatoes were just disappearing one by one, and a while longer to figure out why.