Snails eat ours and occasionally the sparrows and blue tits will have a go at them, especially if there are aphids on the buds.

Sparrows are little hooligans so Owd is right.

Might be birds, but could be earwigs - they operate only at night, so you'll need a torch to go out and check. The other faint possibility is a bee desperate to get at the pollen - they feed pollen to their young.

I have damage like this and it was slugs.

I have had loads of daffs eaten this year and slugs were the culprits.