Decided prevention was better than cure and set about making the bird feeder undesirable to squirrels rather than placing a trap underneath. Replaced the plastic bowl suspended from it (designed to thwart ram-raiding corvids’ efforts) that had huge holes in the side where the bloody rodents had gnawed their way in, with a stainless steel tray (Tesco, £2.50) tightly attached to the bottom with a steel chain. Doing that bit was very, very sweary. Then more steel chain was cut to size (a tight tourniquet stopped the bleeding fairly quickly) in order to suspend the feeder from a corner of the whirly washing line.
I held my breath as I watched a squirrel climb up to the feeder, climb down it to the bottom and try to take a chunk out of the tray. Strike one! It climbed back up and had a go at nibbling through the supporting chain. Failure! It sat, pondered for thirty seconds and made its way back to the ground. Then it slowly wandered off, looking back over its shoulder at the puzzle every once in a while. Success, for now at least.