Adamson is perhaps the oldest living wildlife artist today. Throughout his lengthy career, Adamson has observed, studied and painted the colorful participants in the massive annual waterfowl migration. Although best known for his landscapes awash with flocks of mallards and pintails, on occasion Adamson has painted bighorn sheep, condors and falcons, and the unusual and colorful tropical birds encountered during his many trips abroad.

Part of the appeal of Adamson's paintings, "He paints to the hunter's dream." Although Adamson has never been a hunter himself, many of his paintings, done from the position of a duck blind, evoke memories in the outdoors enthusiast, whether they be of an early-morning close-up view of a flock of mallards or of a stunning landscape experienced. A lover of nature and the outdoors, Adamson has, over his lifetime, donated paintings and prints worth close to three million dollars to raise money for conservation causes. Adamson was a founding member of the Mt. Diablo Audubon Society, which this year celebrated its 50th anniversary.

Viewed by critics in the early part of the century as "mere illustration," wildlife art has since gained in status and popularity, due in part to the emergence of an evocative realism in the artworks that goes far beyond mere illustration and in part to the current concern about vanishing habitats and species. Biographer Diane Inman says, "Without a doubt, Adamson's work has contributed to the overwhelming acceptance of wildlife art in the 20th century."

Adamson's work has frequently been displayed nationally and internationally in the prestigious "Birds in Art" and "Animals in Art" exhibitions, and has been shown at the Smithsonian Art Museum, the British Museum and the Carnegie Museum of Natural History in Pittsburgh, among others. He was named the first California Waterfowl Association Artist of the Year and 1979 Ducks Unlimited Artist of the Year.