A special permission is needed to own cassowaries in the U.S., which mandates that owners must have "substantial experience" in handling the birds and keep them caged. The victim, whose name was not released, was apparently breeding the birds, state wildlife officials said.
Cassowaries, which are known as "the most unsafe bird in the world" have attacked people before and are understood to pose a significant danger to both humans and pet animals.
Deputy chief Jeff Taylor said: "It looks like it was accidental".
He said first responders got a call at 10am on Friday and rushed the man to a hospital for trauma care but he died.
Wildlife officials did not answer phone calls late Saturday and it could not be learned what happened to the bird.
Deadly storms continue their destruction across southern U.S.
The entire town of Franklin and neighboring Bremond lost electricity, with 3,088 customers cut-off across the county early Sunday. Georgia's Augusta National Golf Club is included in the slight risk area Sunday as the Masters golf tournament concludes.
Marvin Hajos, 75, died in hospital after he was attacked on his property in Alachua, about 120 miles northwest of Orlando, in what police described as a awful accident.
Lieutenant Brett Rhodenizer with the Alachua County Sheriffs Office says at this time, it seems the attack was quote 'a tragic accident.' An investigation is underway, and the bird remains secured on private property. They are similar to emus, standing up to 1.8 metres tall and growing to up to 60 kilograms with black body feathers and bright blue heads and necks.
Cassowaries are eaten in parts of Papua New Guinea but in the U.S. but are sought after by collectors of exotic birds.
The Florida Fish and Wildlife Conservation Commission considers cassowaries Class II wildlife, meaning they pose a danger to humans and are subject to specific cage requirements. It can run up to 31 miles per hour through dense underbrush, jump nearly 7 feet into the air and is a skilled swimmer, so it can deftly fend off threats, the zoo says.
It says: "The cassowary can slice open any predator or potential threat with a single swift kick".