closed season, bad idea, these critters are a major pest, maybe il take a photo of a oil seed rape field i have got access to, the damage is immense, (I'm trying to solve it!)
I don't know about decline, there seem to be a few more this year, I'm noticing them where i haven't seen them daring go before (e.g. in the garden when the dogs about, to get a good feed of the ivy in the hedge!)
They need shooting all year round.
Matt