Pellet (kestrel?)

Pellet (kestrel?)

Observation - Pellet (kestrel?) - UK and Ireland. Description: Approx 50mm long comprising grass, beetle exoskeleton and fine plant matter. Found below fence post frequented by upto 5 kestrels actively hunting in dunes and rough grasslands. If this is a kestrel pellet, are they deliberately eating grass to enable th

Approx 50mm long comprising grass, beetle exoskeleton and fine plant matter.
Found below fence post frequented by upto 5 kestrels actively hunting in dunes and rough grasslands. If this is a kestrel pellet, are they deliberately eating grass to enable them to form a pellet in the absence of mammal fur? I couldn't see any prey items being taken, but the birds were making frequent dives in to the grass and remaining there for sometime, but none was seen taking away mammal prey.