Harpy/Avian Society and Technology?

[Cazero]

Couldn't they secure the bowstring to a strap on their bodies, for higher draw-weights? If they have beaks, I wonder what kind of draw-weight they could manage.

It's not a question of weight grasping, it's a simple question of weight ratio.
Since merchandise doesn't migrate, they would need lots and lots of strapping and trained carrying teams. Doable if you don't want to use land roads, but not really efficient compared to the wheel.
edit : wow, I didn't realise it was all about bows. Silly me.