young is my basis for Calling them Screech In the afternoon we heard many of the large Black Swifts calling outside. None of the small (Varix) were present. They were cackling in a great flock high up but would occasionally swoop low while chasing each other. Dad got me on the ivies and we found them to be much larger than we thought. They would make two or three white-throat swifts. This note however is quite weak and doesn't compare with White throat. They rush towards the earth when chasing and create quite a tour of the wings when passing overhead. They surely have a speed of 10! There is a white color about the neck. The flock must have numbered several hundred. They would