Bill ‘Pop’ Bowles, The Memoirs of a Fenland Mole Catcher (Peterborough: Cambridgeshire Libraries Publications, 1986), p. 6:
Mole catchers are not ‘greedy’ fellows, we watch some moles but leave some for ‘seed’! If we caught the lot or let them get too thin that would not suit some farmers, they would think they were paying too much money for nothing, and then they would consider cutting your money down. I know, only too well, they like to see you running around all the time, makes them feel their money is being well spent. Human nature is such that when paying out people like to see action, continuous action, however, a mole catcher uses his expertise, and once he has placed his traps in the right places, plays a waiting game. If you want to leave some moles for later but at the same time want to show the farmer you are trying here is a successful way to accomplish both. Set your trap in the usual way but set the tongue so hard that the mole will be unable to spring it, and he will either go round or under the obstacle his way!
I remember one farmer in about 1930, bet 10 shillings that I could not clear his land, it was heavy rough grass and full of moles. I cleared the fields within a week and he refused to pay me. He thought he had one, but I knew he hadn’t, I picked up all the live moles I could find and dropped them on his land. His 10 shillings cost him double to have them cleared again! He reported me to my boss and said he was so over run, he would have shot me if he knew what I had done! I dropped a few dead moles about but they weren’t caught on his land, the farmer cannot win if the mole catcher doesn’t want him to. It really does pay to be nice to the mole catcher he does have the last laugh!