User blog comment:D2r/Unanswered Questions of Redwall/@comment-1669318-20110425203014/@comment-1669318-20110426003344

Mattimeo Ch 28 "The general led the secret attack...dealing death...to the few old sparrows and late nestlings" Ch 39 "the four survivors who were all that was left of Queen Warbeaks brave little army"

The epilogue is only four seasons after Mattimeo, so it would have seemed like they were recovering, but they would have eventually had to find a way to increase the gene diversity.