I've seen people using these "bird scarers" strung up over their gardens.
If rabbits and pigeons see the silhouette of a bird of prey above them, they are supposed to be scared away. I've seen just laminated pictures of a hawk's face taped to the eaves of buildings and no pigeons or nest so maybe they work.
You could probably make one yourself easily. Cut it out, paint it or just draw eye circles one the wings for extra scariness, make it waterproof, and string it up. The trick is that it must blow in the wind and move around some or the pests will habituate to it.
While your plants are small, I've just put a colander on top of them and a rock to weight it down. You could even make a tunnel out of an old sheet or something as long as enough light gets through. Good luck!