Captain Broom has a tendency to ramble due to his age. As a result of loneliness, he has gone slightly mad and believes that he can still see and speak to the dead members of his warren. These delusions appear to go away once Primrose accepts that they are gone and Broom establishes that the Watership Down rabbits are real. Broom is a knowledgeable and experienced rabbit and warns that they will have trouble when a herd of sheep comes to Watership Down.
During General Woundwort's attempted raid on Redstone, Broom displays that he still possesses the courage and cunning of a Captain of Owsla. Not only does he face several bloodthirsty rabbits, including Woundwort himself, all alone with a cheerful act of a senile old rabbit, but he also successfully fools all of them into thinking that he has an infectious disease which causes them to retreat.
Despite his age, Broom is able to fight two Efrafan warriors at once and survive without any serious injury.