Are every day house hold flies intellegent?

Now before you start telling me what a bozo I am,it is just an observation on my part.Ok,this bozo has noticed that when flies gather they like to do off the wall nasty things.They will fly around your face,land on you your food,disturb your sleep,gather at the trash,well you get the idea.So ya get irritated and you bring out the fly swatter! You get maybe the first two flying around,I regard them as the "Mentally challenged!"Then all of a sudden you can't find a fly any where it's like the mass Exodus just happened and I blinked! The Second I put that fly swatter down,here they are and they brought their friends.So do flies no when they are in danger and death is interment,if so is this intelligence?