I don't see a mechanism for evolving both hair and feathers. Maybe what you take to be hair is actually long stingy feathers, or feathers that further evolved to be hair-like.
But why evolve a totally different covering on the head? Bald eagles have changed their head covering due to the way they feed. Having the environment presented to the head cause selection pressure is the general mechanism: maybe they get bits of stuff and gunk caught in it and it's advantageous to be able to comb it out, thus a simple strand rather than a complex shape.
The human jaw goes against evolution. Birds evolved beaks after flight to save weight.
The pictures also show mammalian breasts. Birds evolved different mechanisms (e.g. crop milk, or simple regurgitation) but they might have evolved the same solutions as mammals in the same way that mammals did.
There are birds that are omnivorous, understand human speech, and form human speech.
What could serve as the basis for the legend would be a flighted bird whose head became featherless (showing bare skin), eyes in a binocular arrangement, and beak retracted to leave a flat face. Perhaps the beak could be colored to resemble lips, All this would be due to the diet and manner of feeding.
The bald face would be supplanted by top-head covering that still protects against the sun but is easy to rinse out, so more stingy.
The stylized breasts in the drawings might be literal observations: circular target-like markings on the chest. These would be typical eye mimic spots to seem like a very large predator from a distance or glimpsed in the thicket. But human men got a different impression.
Now given a naked flat face that sort-of resembled a human, might it then evolve to look more like a human face as a form of mimicry? A glimpse of what might be a human face, as opposed to a deer in the woods, is enough to make a hunter hesitate before taking a shot at something that moved. Other formidable beasts might fear humans and mimicking the part that other animals notice as being distinctive (and they pay attention to the predator's eyes) would let them spook other dangerous animals that they would otherwise fall prey to.