. . . would be the extreamly rare Winnipesaukee Screaming Croakey Warbler. This elusive bird inhabits the deep forest and has been known to fixate on former red-headed females. They draw their victims slowly into the forest by making weird noises. Once in the forest, the victim is attacked and has their hair forcefully removed from their head for nesting material.
Be careful out there!!
On a serious note . . . crows and ravens are both large and loud. They both can make noises similar to what you are hearing. With the young ones in tow, they make a real racket.