A member of the Rail Family, it is closely related to the American Coot, Common Gallinule, and Purple Gallinule. A careless or casual look at the swamphen might lead one to ID it as a Purple Gallinule - one that has pumped up on steroids.
For comparison, here is the Common Gallinule (aka Common Moorhen) and the American Coot ...
I am concerned when captive birds escape; they can have a negative impact on native species. But I will say this for the Purple Swamphen, it has a very impressive tush ...
Good Birding ! !