Mystery marigold muncher

On a patio area I have some home grown flowers/bedding plants in trays awaiting planting. Several of these are French marigolds which are starting to flower in their cells. I went to take some  cells from a  tray to plant out and found masses of marigold flowers underneath.  Looking at the marigold plants something is taking off the tops and flowers and hiding them.  I have a feeling its four legged rather than two because of the 'hoarding' aspect. Anyone else seen this sort of thing? I have taken steps