We have two distinct types of Gallinule. They have the same annoying habit of screaming out loud, but look different. These are primarily marsh birds.
The Purple Gallinule is very dark, the usual red ‘plastic vinyl’ beak, and iridescent colors in the right light. This bird is tropical and prefers Florida and southern Georgia in the US.
The Common Gallinule is more of a brown color. The same red beak, and loud scream. They are semi-tropical and will go up to the Mid-Atlantic USA during the summer months.