Thidwick's antlers
Thidwick's antlers represent his usefulness to the animals who live there. They essentially use Thidwick for his antlers and take advantage of him because they want to live there. In this way, the animals do not respect Thidwick or consider his feelings. For example, rather than seeing the antlers as a part of Thidwick, the animals simply see the antlers as their home: "These horns are our home and you've no right to take, our home to the far distant side of the lake!"
The Herd
The Herd represents Thidwick's sense of community, home, and familiarity. Through taking advantage of Thidwick, the animals residing in his antler's isolate Thidwick from his herd, detaching him from feelings of safety.
A Big Heart
Thidwick is referred to as having a "big heart" in the title of this story. Thidwick's big heart is a symbol that represents his kindness and generosity. Throughout the text, we can see this in action, with Thidwick giving up his antlers in the interests of the other animals.
Public Hotel
Thidwick's antlers are described as being like a "public hotel," which refers to the fact that seemingly anyone is able to stay there. This is unfair, as Thidwick can only withstand so much.
The Guests
In this story, the guests on Thidwick's antlers symbolize unkind people who will take advantage of others. While Thidwick is kind enough to let the bug live on his antlers, the bug is then cruel enough to take advantage of the moose, inviting his friends to live there too. When they see this is causing Thidwick a lot of suffering, they don't have empathy for him.