This is the social butterfly in your yard! Other birds will listen for him to determine whether or not it is safe to go to your feeder. He warns of danger with the number of dee, dee, dee's he calls out. Once he gets to know you, you may get a Dee or two but not much more. If you're out in the yard and suddenly he starts to sound the warning, look up in the sky for hawks (Crows cawing is a good sign) or search the ground for a cat. I've seen Dees at the feeders early in the morning and suddenly they sound the alarm. Once around the yard usually gets the cat out from under the bushes.