For pure wildlife art Maynard Reese is hard to beat. He is still alive at age 95 and painting! He spent more days afield across the world than your average dozen committed upland hunters.
He still holds the record number of Federal Duck Stamp awards.
From Wikipedia:
The first Federal Duck Stamp, designed by Jay "Ding" Darling in 1934 at President Franklin D. Roosevelt's request, depicts two mallards about to land on a marsh pond. In subsequent years, other noted wildlife artists were asked to submit designs. The first contest in 1949 was open to any U.S. artist who wished to enter. Sixty-five artists submitted 88 design entries that first year. The number of entries rose to 2,099 in 1981. One artist, Maynard Reece from Arnolds Park, Iowa, has won the competition a record five times as of 2011, winning in 1948, 1951, 1959, 1969 and 1971.[4] This is the only art competition of its kind sponsored by the U.S. Government.