Can anyone identify the damage culprit on my primrose?

[Justmuddlingalong]

I've been out at night with a torch searching for slugs and snails but didn't see any. Does anyone have any suggestions or advice? TIA.

Sparrows and possibly other birds are reputed to peck at flowers, particularly yellow ones.

Agree with Mere, birds are likely culprit in the absence of slime trails.

I have the same with my pansys. They've gone for black and yellow indiscriminately and I'd just blamed slugs without investigating. It prob is birds - though I've never spotted them at it. I'll watch more carefully from now on.

Thanks all. They definitely have a preference for the orangey yellow ones, all the rest are fine.