As of my knowledge cutoff in 2023, Jon L. Dunn is a well-respected bird expert and author, widely recognized for his contributions to ornithology and birdwatching in North America. He is best known as a co-author of the National Geographic Society's "Field Guide to the Birds of North America," which is a popular and widely-used field guide among birders. Dunn's expertise in identifying birds and his comprehensive knowledge of avian species have made him an authority in the birding community. He has also been involved with various ornithological organizations and has contributed to many projects and books aimed at bird conservation and education.