If I have a bird EVER do that, he is either being run off by another bird or something is wrong with the mix. I have tasted mine after two weeks. I'm not coming over to taste it, but I would make some new and rinse the feeder with very hot water. I certainly would not put more than 16 oz. in the feeder or less. Must be soap or chlorine in it if the mix is 4-1 or close. With 8 feeders currently I don't run and fill a feeder when it goes dry, but one dip into it and moving to the next will tell me. My stuff is never soured, but I have been told in person and on the internet that they will not drink that either. No ants or anything on the feeder?

NOT SURE WHY. I HAVE 4 FEEDERS AND ONE BY CP ROOM WINDOW SO CAN WATCH THEM. GOT SUGAR WATER READY TO FILL ONE. HAD 4 HUMMERS AT 1 FEEDER AND ONE IN WAITING LINE. THIS IS MOST I EVER HAD.I USE 4-1 RATIO. JUST WASH OUT AND REFILL. YOU DON'T HAVE STRAY CATS BY DO YOU? HOPE YOU GET SOON.