Big Mama is a motherly figure in the movie, an owl who lives close to Widow Tweed's home. She is generally warm, helpful, and friendly to everyone, as she seems to befriend not only Tod, but is also a friend of Boomer, Dinky, Vixey, and Squeaks.
She coordinates a plan to help the orphaned baby fox, Tod, and becomes a big help throughout the film. She advises Tod that being friends with Copper isn't a good idea, and even helps him find Vixey when he's dropped off into the forest.
She seems to possess a great amount of wisdom.