Mr. Worple in his spare time was what is known as an ornithologist. He had written a book called American Birds, and was writing another, to be called More American Birds.
2013 January 1, Paul Bartel, Ashli Moore, “Avian Migration: The Ultimate Red-Eye Flight”, in American Scientist[1], volume 101, number 1, archived from the original on 5 March 2016, pages 47–48:
Many of these classic methods are still used, with some modern improvements. For example, with the aid of special microphones and automated sound detection software, ornithologists recently reported […] that pine siskins (Spinus pinus) undergo an irregular, nomadic type of nocturnal migration.
