Gus is a female Great Gray Owl.  Her age is unknown; she was hit by a car and rescued in 2008, coming to the Alaska WildBird Rehabilitation Center with a right wing broken at the elbow and an injured left eye.  The eye was unable to be saved, but even with one eye she could have successfully hunted, since hearing is much more critical to the Great Gray Owl's hunting prowess.  The broken wing prevents her being able to hunt and survive in the wild. 

In raptors, such as owls, the female is generally larger than the male.  Gus is a small bird, it was initially thought she was male, but later DNA testing showed she is a very small female.