Either Pyoko is lying through her teeth or the crows in that neighbourhood are metal as fuck
Birds can be fucken savage. Back on the farm I'd always bring a pitchfork with me when collecting eggs. We kept a rooster for breeding and that fucker went for me every time I entered the pen. I'd use the pitchfork to pin his neck to a straw bale before entering the coop. Occupying an enclosed space with pissed off 25lb bird is all sorts of not fun.
That's the territorial harem-keeping males for ya. Crows OTOH don't go after things significantly larger than themselves unless their nest's being threatened or they're trying to drive off one of their relatively few potential predators, and I rather doubt our sparrow-harpy here has the kind of flight profile that'd trigger a torches-and-pitchforks mobbing response like birds of prey do.
I mean its fine for dumb monsters who just eat people but not an intelligent race.. she couldnt feed herself- she couldnt have dressed herself.. couldnt build or make anything.. etc etc.
I remember watching an interview with an armless woman, one part of which touched on her being able to dress herself with only a stick attached to a suction cup for assistance. She'd also managed to ride horses, which is how she died(her foot got stuck in the stirrup when she fell out of the saddle).
But you're right that harpy civilization wouldn't be building anything too precise on its own(coarse building is just fine, given that birds tend to, y'know, build nests).
Once saw an armless dude cheerfully surf the Internets by typing with his toes (looked kinda precarious balancing on the chair with only his buttocks tho), and human feet are Hell of a less prehensile by default than those of perching birds so yeah. Still gonna put some hard caps on the amount of material culture they can produce and operate on their own though but, eh, they can farm the fine work out to the groundbound hairless apes.