Originally Posted by CitrusHigh
Birds are unlikely to go for established seedlings but freshly sprouted seedlings are a different matter altogether.
If I were you what I would do is to cut out the shape of a hawk in flight, life sized and hang it from a branch overlooking your patch(es). An owl or hawk statue is a good idea too, like someone mentioned above. However when choosing a hawk silouette I'd choose a bird eating hawk from your area. For example a red tailed hawk here doesn't get treated nearly the same as a bird eating sharp shinned hawk, by the birds. When a red tailed comes in to the area it usually will have a few larger birds mobbing it, but when a sharp shinned hawk comes through, every bird in the area pays attention and all they want is for that hawk to leave the area, because they can't do anything else (like eating, sleeping, mating, preening, etc) while there's a killer nearby.
Netting is also a good idea.
You should also find bird tracks if there's bare soil where they were stealing from you and feces as well, bird defecate often so there's usually some when they feed in one spot. repeatedly.
Also did the thief take the whole seedling/sprout or did they chew them up and leave pieces around, that will help you determine the culprit even more surely.
Chew them up? The sprouted seedling was the size of 1 bite. It was literally the cotyledons. Some unfolded, some folded still just sprouted.
The freshly sprouted ones just like it got chomped off at the top, and all there is, is a 1cm tall stem with a rotting brown tip on it, as if something bit it off.
The others, the plugs got ripped up and the cotyledons ripped off too. I know it's birds because the same feathers are everywhere.