Richard Adams AMA
https://www.reddit.com/r/IAmA/comments/1n3quw/i_am_richard_adams_author_of_watership_down/
Author Richard Adams answers readers' questions on Reddit.
Watership Down Movie
https://www.youtube.com/watch?v=Q1n8E3ntWUg
The 1972 animated film adaptation in its entirety.
Bunnies and Burrows
https://en.wikipedia.org/wiki/Bunnies_%26_Burrows
A description of a Watership Down inspired role-playing game (like Dungeons and Dragons). You can download the game here! http://www.drivethrurpg.com/product/82542/Bunnies-And-Burrows