Hopefully this page will answer your questions!
What authority do you use?[]
I'm not sure what it's called, but we use Taxonomy in Flux. It is maintained by John Boyd III.
Why?[]
Because Wikipedia fails at bird taxonomy. TiF is the most up-to-date site I've seen so far. In fact, it was last edited on August 24, 2014!
I see a mistake! Can I change it?[]
Only if you use TiF. If it's not on TiF, then don't use it.
I see a species that hasn't been added yet! Can I add it?[]
Of course, as I said above; as long as it's on TiF, it's fine. Make sure you use the proper layout, though.
But [insert name here] uses a different approach![]
Well, good for them, but I'll never use it.
Can I see an example?[]
Sure. See Osprey or White-headed Vultures for examples. Also, the nav-bar also uses TiF!
Can I see a comparison?[]
All Birds Wiki:Comparison of checklists.
Are there any taxons that have all been added?[]
Of course! Most of the categories are hidden, but you can check this one out if you want to: Taxons that are complete