Frederick, Oklahoma, Tuesday, 4/5/05. Hackberry Flat is a bird-watching paradise where more than 190 bird species have been seenentified. Each year thousands of visitors flock to Hackberry Flat to watch birds. The height of the bird-watching season is between March-May. Biologist Kelvin Schoonover uses a spotting scope to look at birds out on the flats. Staff photo by David McDaniel.