Not sure how this process works, but some corvid tags need to be fixed. Right now raven --> crow because "a raven is a type of crow", but that is false. However,

- A raven is a type of corvid

- A crow is a type of corvid

- A blue jay is a type of corvid

etc.

For more information, see http://en.wikipedia.org/wiki/Corvidae

It took me a minute to work through all that, but I think that's a great idea. It'd improve the organization of those different species in relation to each other, and as a group. I like it.

Full support.
Raven is implicated to Crow? I wonder how and when that happened.. Needs to be fixed.

I'd also suggest adding magpie -> corvid, and corvid -> avian.

I found conflicting information about whether or not ravens are crows. Wikipedia defines all members of corvus as crows. By this definition, ravens are crows, and so are jackdaws and rooks, but not jays or magpies. An ornithologist, by contrast, says that ravens are not crows:

Crows and ravens, although in the same genus (Corvus) are different birds. (Think of leopards and tigers; both are in the genus Panthera, and are obviously related, but they are quite distinct animals.) The words "crow" and "raven" themselves have little or no real taxonomic meaning. That is, the Australian "ravens" are more closely related to the Australian "crows" than they are to the Common Raven (Corvus corax). In general, the biggest black species, usually with shaggy throat feathers, are called ravens and the smaller species are considered crows.

http://www.birds.cornell.edu/crows/crowfaq.htm

FWIW, I still think raven --> crow should be removed

I can agree to the de-implication even though the distinction will be lost on 95% of people, but this new tag sounds like a bloat tag. Does there really need to be three separate species tags for a few birds?

That's a valid point.
Mammals have three levels of tags (fe. Cat -> Feline -> Mammal), but since there's less avian images, two levels should be enough.

Maybe just implicate all those species directly to Avian?

Genjar said:
That's a valid point.
Mammals have three levels of tags (fe. Cat -> Feline -> Mammal)

From mammal's wiki:

PS: It is unnecessary to use the tag "Mammal" on e621

Mammals don't have three levels of tags since this is probably invalid tag.

I know. I got distracted by someone's avatar. ;)

Dolphin -> Cetacean -> Marine would've been a better example.

Cetacean's useful though, as it covers dolphins, whales, orcas, and narwhals. Not to mention there are pages of whales tagged cetacean and not whale. And marine is a keeper for obvious reasons.