This Limpkin was standing on the railing of the observation deck at the Onion Fields bird site.
allaboutbirds.org says “it feeds almost exclusively on apple snails, which it extracts from their shells with its long bill. Its screaming cry is unmistakable and evocative”. They are sure right about the call. The noise is piercing and sounds like I would image a Pterodactyl would sound if it was standing a few feet from you.
I think that Florida may be the only place in the US that these can be found. They are mostly in South America.