@janturnbull Yes the yellow is the shell, the red is the hard seed coat. Bittersweet is a vine that can strangle your trees, so they have to be kept at bay. The birds enjoy eating the berries (songbirds, ruffed grouse, pheasant, bobwhite, etc), but they are not for humans.
What wonderful colors - and I love that you were able to catch both the berry and the popped open ones. That is so neat. Enjoyed the information about them.