If it's like the concept of "categories" in MediaWiki-like software (ie.: Wikipedia), then it is my understanding that such functionality is already available through this plugin. You just need to call the tag the appropiate path, something like:
for page "Peregrine Falcon":
{{tag>:animal:bird:falconidae}} (notice the colon after the ">")
It is explained here:
http://www.dokuwiki.org/plugin:tag#tag