http://community.wikidot.com/howto:create-an-automatic-navigation-without-parent-childs

What you can use are

A) the soft_categories ( like wikipedia does ) :

Every article - a page in the "default" cat. or "specific:" like your "parrots: cat :) - can have a link to a "category- page" like your

• "parrots:amazons" or
• "parrots:Macaws"
• "parrots:whatever" - where the aricles belongs too.

These are pages holding the "headers" of your categories and shows all "linked" pages inside these groups by using the "module backlinks"
See * http://www.wikidot.com/doc:backlinks-module

B) the tags for indexing your pages:

You can give every article some tags like "parrots amazons Macaws whatever…" . This helps not only in the tag cloud to find some pages on an easy way;
but you can use the "ListPages" module on some "header" pages ( like in the section A) before) with a (fixed ) tag selection like "+parrots,+amazon" which gives you all articles tagged wizth these 2 tags only!

Hope this helps to imagine what is possible?

Is it possible to make categories within categories?

For example, I have a group called 'Species Discussion' and one of its categories is called 'Parrots'. Is it possible to then create more categories within the one called 'Parrots', such as 'Amazons', 'Macaws', etc.
If so, how?

Thanks for your help. :)