Started doing some to-scale size references for Redwall-verse species, including some speculative ones (and corrected identifications, such as Jacques's few infamous instances of "crested lizards"... those are newts, buddy).
All the creatures in this series are obviously much less tiny or gigantic in proportion to each other than their real-life inspirations. Kinda got to do that to make a building useful for both small mice and massive badgers and otters!
Here we get our first examples of sizes that the birds come in! I very much took into account that birds often look bigger than similar-sized mammals and in fact often have quite a bit less mass than a same-sized-lookin' rodent due to the fluffy feathers (The sparrow here, despite fluff taking up the same space as an average mouse, actually would be a bit smaller and would weigh probably only half as much). So you see the very smallest category among the bird species will be even a bit smaller than the smallest creatures that have a more anthropomorphic treatment--which are the small amphibians beyond any doubt. I included the three newt species which have either appeared or would definitely be present based on geography... and also one non-newt salamander species that I would have just found very neat to appear somewhere, the Alpine Salamander. Which is, oddly, a viviparous species due to its very... alpine home! Also need to have something which is clearly labeled "salamander", since the confusion with "newt" and lizards seems bizarrely omnipresent not just in Redwall, but in public knowledge. Y'all don't know nearly enough basics about the difference between reptile and amphibian (you're doin' better than many Redwall characters if you even know there's a difference!).
On this page, Newts are without exception classed into "Vermin", and I would speculate other salamanders would be lumped into that as well. Of the large bats here, I have done some speculation and think that the Greater Horseshoe Bat and the Greater Noctule--being predators of small vertebrates and passerine birds respectively--would get classed into Vermin as well. The Mastiff bat and the small birds shown here are considered to belong to class "Goodbeast" (though notably there are other bird species that would rival the ones shown in size which would get the "Vermin" class, such as Starlings).