What next? And yet, why not? Birds that submerge to secure their food are seldom seen by the casual observer, but many of them have unusual characteristics related to their special ability. The loon, a fast swimmer that can easily overtake a fish, is helpless on land; the grebe can rise or settle in the water like an elevator by compressing its body feathers and forcing out the trapped air; cormorants used by Japanese fishermen are so regularly deprived of their catch that they have to be shown how to feed. An out-of-the-way topic, up to Mr. Ripper's usual standard of clarity in pictures and text.