Silver was a rabbit who was a junior officer of the Sandleford Owsla. According to Bigwig, the other Owsla officers teased him, making fun of his fur and saying he only got the job because Silver was Threarah's nephew. Bigwig brought him along on the journey because they were good friends and Silver was dissatisfied with his life in the Sandleford Owsla.
Silver and Bigwig often worked together with scouting and Owsla business. When they had to scout out the area near the Warren of Snares or investigate when the injured Kehaar landed near the Watership Down Warren it was the two of them to do it.
Silver proves to be very tough and strong, like all the other Owsla officers. He was in Captain Holly's party which went to Efrafa to bring does back to Watership Down, and he was the only one to escape uninjured.
When he, Holly, Strawberry, and Buckthorn were escaping Efrafa, Silver detected that the Efrafans were still after them. He is almost as strong as Bigwig but does not have the same boldness or confidence as him. This is shown in the book when he says he will go back to Efrafa, as long as he do not have to go in by himself.
In the battle with Efrafa, Silver helped to defend the outer runs before all the Watership rabbits retreated further into the warren prior to Woundwort's final assault and battle with Bigwig. After the battle he became a senior member of Bigwig's Owsla.
In the film, Silver has a role the same size as his book counterpart, appearing as a large grey rabbit with a rather slow personality. He appears to be more like the character Hawkbit from the book, sharing his personality and his role in questioning the authority of Hazel.
At first, Silver is just another ordinary rabbit in Sandleford Warren; but shares Hazel's view of the warren's Owsla being too mean. And so, Hazel, Fiver, Bigwig, Blackberry, Dandelion, Pipkin, Violet and himself depart Sandleford Warren. Like a couple of others in their group, Silver doesn't entirely trust Hazel and Fiver. After the incident in which Bigwig was caught by a snare, he seems to accept the leadership of Hazel.