Onions uprooting themselves

Quite a few of my Sturon onions are sitting on the surface of the soil. Some of them have even fallen over but are still rooted in the ground. Having planted them slightly deeper than recommended (to stop the birds taking them) I'm a bit unsure what to do. Should I earth the fallen ones up a little?

It's the birds.  Can you stick a bit of net over until the roots get stronger?

make a deepish thumb print under them and ease back into ground and then earth up a little and then water well and net over. If careful you can even replant.
R

Pushing them back in, however carefully, can damage the roots and stop growth. The simple way to sort this problem is to hill them up a bit as you do potatoes and firm the backside of the rake against the hill. I've also seen this done with beets which sometimes pull themselves out of the ground.

They tend to do this if the ground underneith them is a bit on the firm side.
As the roots go down they push the set up.
Like said before, just earth them up a bit and as the onion grows it will push the earthing away as it swells.