Something attacked my onion seedlings

I planted some red onion seedlings in among some white onion seedlings which had established themselves last Monday only to find this evening they have been attacked by something either bird or animal.
They even managed to dislodge the name tag.

I will post photos in a few minutes when I resize

This is how they looked on Monday evening 
   

Here you can see where they have been pulled up and chopped 
   

Here you can see them chopped and on the top left holes where they were pulled out
   

Better close up of the top left
   
Better close up of the chopped plants
   





Anybody ever experienced this before or any ideas ?

Thanks