Sure its birds? Have any squirrels around? Try putting some hot stuff around your plant cayenne, hot sauce etc.

I have a fenced yard....that keeps my chow chow in...and varmints out!

Squirrels. They dig holes in my beds and pots. looking for nuts or burying them. Good luck. I relocated a dozen or so and gave up. There seems to be an endless supply.

john

I put bird netting around my plants.
Cats think my pots are litter boxes.
Birds like to eat my sweet peppers too.
They never dig in the soil.

Fences will keep your dogs in, but not cats, rabbits or squirrels out.

Try placing some rose branches or raspberry canes in the pots. That may discourage them from roosting.