Earthworm, another additional food source

Earthworm that I found in my backyard during digging the soil can be an additional food source for the shama thrush.  I know these earthworms are safe to feed the birds because I do not spray any insecticide/ or any harm chemical in my yard.  All the birds are eating the earthworms and even feed to their chicks if given plenty.  My backyard doesn't big enough to have unlimited supply of earthworms so I consider feeding earthworms as treat food, not a staple food that can be feed everyday.