What's the rabbit population like around you MM?
Everything has a knock on effect. I'm not saying rabbits are a main source of prey as stoats will happily take ground nesting birds. Or pretty much anything they can sink their teeth into. Especially a mother with hungry kits.
A decline in hedgerows and large amounts of land being turned over for crop growing has a slight impact.
Chances are they are there, your just not seeing them.