Daryl D. Tessen

Daryl D. Tessen, age 85, one of Wisconsin’s premier birdwatchers, earned his heavenly wings when he passed away on July 28, 2025 following a brief illness, and he is now happily watching warblers that don’t fly away and shorebirds on a mudflat close enough to see. Daryl was an only child, born on August 25, 1939 to Fred H. Tessen and Adeline “Pat” (Pagel) Tessen. He grew up in a loving home with parents who instilled in him a love of nature and a passion for birds.

Daryl graduated from Appleton High School in 1957, and went on to study at Lawrence College earning a degree in biology. He later received a Master’s degree at Colorado State University.

For many years he taught biology at William Fremd High School in Palatine, Illinois, where he was affectionately referred to as “Mr. T” by his students. After his retirement in 1994 he returned to Appleton to be near his mother.

From an early age Daryl was captivated by birds, and that fascination continued throughout his entire lifetime. He became a familiar face in the field—he was highly skilled and knowledgeable and probably considered the most “famous” birder in the state. He was especially fond of birding in Wisconsin, where his pursuit of birds took him to every corner of the state – many times. It is no surprise that his extensive travels led him to become editor of the popular bird-finding guide book, Wisconsin’s Favorite Bird Haunts and the multiple editions that followed. These books provided detailed information, maps and artwork for hundreds of birding sites across the state, and are still used today, although now updated and available in a digital format. He co-authored a field guide to the Birds of Minnesota and Wisconsin in 2003, and was the Western Great Lakes Region editor for American Birds for 24 years.

In addition to the countless miles he traveled across Wisconsin, Daryl visited numerous other birding hotspots around the country, ultimately tallying a life list of 778 bird species. He made 60 trips to Yellowstone National Park, traveling annually by car—initially as a boy with his parents, and later with his mother (who kept beautifully detailed journals of their adventures), and then made several trips on his own. His final visit was in 2022 when Yellowstone experienced torrential rain and flooding.

Daryl’s birding forays in Wisconsin over the years paid off in a big way, as his state life list stands at a remarkable 437 species (far ahead of anyone else) with his last new bird being a Kelp Gull in Milwaukee on June 2nd.

A member of the Wisconsin Society for Ornithology for most of his life, Daryl served on the board of directors for 40 years – including terms as vice-president and president. He helped create the WSO Records Committee, and was the Autumn Seasonal Editor for the Passenger Pigeon journal from 1966 to 1976, compiling and analyzing fall bird reports for the publication. He spent many years as the Awards chair and was himself awarded multiple times, including the prestigious Samuel D. Robbins Lifetime Achievement Award in 2012.

A memorial visitation will be held for Daryl from 10-11 AM on Saturday, August 23, 2025 at Zion Lutheran Church, 912 N. Oneida St, Appleton, WI 54911 with a memorial service to follow at 11 AM.  Daryl will be laid to rest at Highland Memorial Park following the service.