Chandler Robbins, a research ornithologist known as the “dean of the bird conservation world” and one of the last links to Rachel Carson, died on March 20. The Laurel, MD, resident was 98.

Robbins joined the U.S. Fish and Wildlife Service in 1945 as a junior biologist at what is now the Patuxent Wildlife Research Center, after graduating with a degree in physics from what was then Harvard College, followed by a teaching stint. He worked with Rachel Carson at Patuxent and participated in some of the first studies on the pesticide DDT’s effects on eagle and osprey reproduction.

In 1966, Robbins co-wrote Birds of North America: A Guide to Field Identification. The Golden Guide has sold more than 5 million copies and introduced millions of people to the pastime of identifying and enjoying migratory birds, according to an obituary written by Heather Dewar of the U.S. Geological Survey, where Robbins spent much of his career. The book is still in print, and avid birders often take their worn copies out on hikes.

Robbins launched the pioneering North American Breeding Bird Survey in 1967 with a simple method: Wake before dawn and drive a half mile, then stop and count the birds seen and heard, according to the USGS obituary. This survey became the model for thousands of bird counts conducted across the country and is the main avian monitoring program in North America.

“The Breeding Bird Survey changed the scope of bird research,” Patuxent’s director, John French, said in the USGS appreciation. “We began to focus not just on endangered species, but also on common birds and the conditions that allow them to survive and thrive. We also realized that migratory species are affected not just by changes in their habitats in North America, but also by what happens in their overwintering sites in Central and South America. We began to take a broader view of the science of bird conservation in part as a result of Chan Robbins’ work.”

Though retired since 2005, Robbins, known as “Chan” to colleagues, still came to the office in Laurel three days a week. He was known for carrying a battered pair of binoculars, resisting offers to upgrade because of all the birds his had seen, according to another tribute posted by the Fish and Wildlife Service.

Robbins was also known for banding the oldest known wild bird in 1956 — a Laysan albatross named Wisdom. He re-banded her in 2002, and in February, Wisdom hatched another chick on Midway Atoll in the Pacific Ocean. She is 66 years old.

Wisdom has her own Facebook page, where those who knew Robbins and his work are leaving tributes. One, posted the week Robbins died, read: “Wisdom — so sorry the person who ‘discovered’ you has passed. But there are many more who know your story simply because he lived.”