Agreed. However, a zero-roll jump-flap takeoff using the wings as the launching mechanism is likely possible. The fact that birds use their legs so heavily for takeoff is probably the main thing that limits their size. The weight of the landing gear increases with the cube of the bird's size while the wing area only increases with the square. At some point, the burden of carrying the weight of the landing gear becomes too big to bear.The jump-flap vertical takeoff of small birds will probably not be possible for any manned ornithopter due to actuator weight (both leg and wing actuators).
In contrast, pterosaurs used their wings to launch. The launch system is the same as the wing flapping system. That weight is shared, rather than having two separate systems. This is likely why pterosaurs were able to grow to be the size of an ultralight aircraft.
I like your feathered wing model. Please tell us more about it and your goals.