He's always been a bit vocal but the last few days have been brutal. He has discovered the windowsill with the blinds down and sits there for AGES meowing at seemingly nothing. It is driving me round the bend!
Nothing much has changed recently other than me working more than usual, so I'm out quite a bit. No food change, flat (mostly) tidy, litter tray cleaned etc. I'm at a loss of what to do. I'm going to phone the vets on Wednesday morning (left phone at work and not there again until then) but anyone know WHY he might be meowing constantly? -and any ideas
on how to make him be a bit more quiet- 
I have two cats so I don't know how it could be loneliness as they get on well and I'm not out that much, plus other cat isn't bothered at all!