Are Horses More Useful to Humans Than Pigeons? And Other Letters to the Editor Credit...Kim Ludbrook/European Pressphoto Agency April 2, 2021 To the Editor: In Nate Blakeslee’s mostly favorable review of Matthew Gavin Frank’s “Flight of the Diamond Smugglers: A Tale of Pigeons, Obsession, and Greed Along Coastal South Africa” (March 21), Blakeslee writes, in reference to pigeons, that “no other animal aside from the dog has been as useful to humans.” Really? I daresay that in a contest between pigeons and horses as to usefulness to humans, the horse would win by several strides. Michael Golden To the Editor: