I sponsor Ph.D. and M.S. students. Those with tropical field experience or experience in collecting specimens have an advantage.
Applicants lacking a strong background in bird natural history are at a great disadvantage.
Although I don't put much emphasis on GRE scores, the Graduate School and the Dept. of Biological Sciences do. Those with GPAs lower than 3.0 will also have a difficult time being admitted to the Dept. of Biological Sciences.