Terror Harpies

A mid-to-large sized breed that, while perfectly capable of flying, has largely adapted for a life as ground-based hunters. Their feathers are shaggy and often with dull colors, intended as camouflage in savannahs or areas of high vegetation, and feathers at the back of their heads are erectile and quill-like, useful for sending messages to one another as they hunt in packs. Crane-like legs are perfectly evolved to run through enormous distances, and deadly claws at their end give pinned prey little to no chance to escape before being crushed

Terror Harpies have notoriously sour and impatient personalities, even compared to other harpies. They have a great desire for speed and even greater respect for the ways of the hunt, and often dismiss other races on the grounds that they're not as efficient killers.

And yet they're surprisingly caring mothers, perfectly willing to wait up to a whole month without food until their eggs hatch

this is a nice idea here
I think they are a bit similar to Razias, but I like that trait of head feathers used to communicate throug long distances. ^^

But Razias can't fly, these can, if they don't do it much

Maybe they could be closely related breeds, with the Terror Harpies being the larger, meaner of the two. Like dogs and wolves, really