In the 19th century, a heated dispute arose over the house sparrow and its introduction into North America. Elliot Coues and Thomas Mayo Brewer held opposing opinions on the matter which they defended their entire lives.
Research:

Elizabeth Peratrovich
43:42

SYMHC Classics: Dr. Lucy Hobbs Taylor
29:58

Behind the Scenes Minis: Carry-on Bags
28:38