[Jemian]

Pileated and Ivory is akin to a crow and raven in appearance

I've seen all of those birds you mentioned. The woodpeckers look nothing like crows and ravens.

[Tijeras_Slim]

I think the poster was commenting on the similarity of those two woodpeckers being close like crows and ravens. (I’m a huge fan of ravens.)

[Theoria]

In reference to a crow and raven in how close they appear. Just as how a pileated and ivory billed are similar.