Simplify the following text for a Grade 12 native English-speaking person.
Original: The Javan Hawk-eagle , Nisaetus bartelsi ( earlier under Spizaetus ) is a medium-sized , approximately 61 cm long , dark brown raptor in the family Accipitridae .
Simplified: The Javan Hawk-eagle , Spizaetus bartelsi is a medium-sized , approximately 61 cm long , dark brown raptor in the family Accipitridae .