Much of the early history of attempted flight is about failure inspired by bird flight. It wasn't until the idea of flying stopped trying to incorporate bird-like flapping movements that it started to see any kind of success.
Wing-propulsion is a dead-end for human flight.
In fact, for large birds, wing-propulsion is also not as efficient as it is for smaller birds, because of the way that scaling works - if you double a length, you get four times the area, and eight times the volume (and mass).
Larger birds tend to spend most of their flight soaring, making use of the movement of air itself - and many of them, far from flapping, are able to lock their wings into place.
There are many aspects of bird flight that have successfully informed human flight, but using wings for propulsion is not one of them.