For Creationists.

[Smaug]

The bats belong to the same 'kind' as the birds according to the Bible, don't they?

pretty much in reality we class animals by species and sub types.
bible pretty much says that wolf is a kind and a dog is a kind of wolf.
or a red panda is a type of bear. reality red panda is a giant panda and racoon. very rare btw.

The purpose of any classification system is to set up an equivalence relation in a set of entities. It's obvious that almost everyone consciously or unconsciously invents or adopts all sorts of classifications. But when professionals set up a classification system and construct an equivalence relation in an applied field (such as Biology) they try to choose the most adequate and up to date comparison properties (good to point out here that for a non-professional these properties may seem obscure or irrelevant). Also they try to make it as objective as possible. On the other hand, fundamentalists rely on Bronze Age knowledge and subjectivism. In conjunction with the fact that they are heavily indoctrinated they literaly aren't above Bronze Age people when it comes to their general world view and their attitude towards science. That's why they have this primitive notion of 'kinds' and aren't going to abandon it for the sake of more up to date and precise knowledge.