Character Analysis
Before turning into a living hotel, Thidwick spends his time in a moose herd, just hanging out and munching the moose-moss. But moose don't live in herds, you say, they're solitary creatures. And indeed, you are correct.
It's also true that Thidwick's herd consists of all males since they sport antlers on their dome, making them even less likely to hang out together. But moose also don't eat moose-moss or walk around with foxes and bears on their heads, so let's just agree to let some facts slide since this is a children's story and all. Plus, more important for our analysis is what purpose these guys serve in the story rather than how they defy the laws of Mother Nature.
And that purpose is that they provide early access to the moral of the tale. They give Thidwick the hard truth before he's willing to hear it.
When Uncle Woodpecker starts drilling into Thidwick's antlers, the herd tells him to get rid of the pests. Thidwick responds he can't because they are guests, and the herd replies:
"If those are your guests, we don't want you around!
You can't stay with us, 'cause you're just not our sort!"
And they all turned their backs and walked off with a snort. (19.2-4)
This might seem super harsh at first glance, but as we read through the story and see how Thidwick suffers, we realize that the harshest thing about what these dudes say is how true it is. It's too bad they decide to bounce on their herd buddy, but hey—everyone's got their own take on how to handle tough love.
And since the moose know Thidwick is being taken advantage of, but Thidwick isn't ready to hear it, the herd kind of has to move on without him. By not being "the sort" of moose they are, after all, Thidwick can reap all sorts of dangers on the herd. For example, Thidwick's unusual guests could gain the attention of a group of trigger-happy hunters, which would be bad for the herd as a whole. Just sayin'.
So though the moose herd's words may seem pretty mean, they know what's good for them. And they smile when they see Thidwick has evicted his pest guests and welcome their wayward friend back into the fold.