Primula problems

macsquirter

For a year I  have had a pot of mixed colour primulas on my second floor balcony. Something is eating the purple flowers only. I can't see any slugs and have wrapped copper tape around pot just in case a slug with crampons(?) has decided to risk the climb. Any ideas as to the culprit?

Oldtyke

Birds?

 

Elusive

My bet is small green caterpillars, inspect closer and you will find them hiding.