No idea how they know time I do not pretend to be that smart. However this is common on about every lake we have with feeders. You are 100% correct 5 mns b/f nothing right before ready to go. It is survivial instinct to know this stuff. FYI ducks and geese have it down as well. They fly in a few mins before it goes off. ALso herons have it down I watched a GBH in S.C. fly by he landed by the feeder it went off secs later and within about 30 secs he caught a BG. He then flew back by me to other side of pond. Sure enough there for about 2 mins feeder went off. I watched him do it once more on adjacent lake then got bored/pissed and went back to work.
