This species is reportedly a fairly recent arrival to Florida with the population exploding in 2012. An interesting comparison from former and current breeding bird atlas projects is here. The subspecies breeding in Florida is uncertain as both naturally occurring birds from North America (D. a. fulgens) and escaped birds from South America (nominate) may occur. The latter have a gray collar around the back of the neck which is not evident in these birds suggesting that they are of North American origin.
Digiscoped with Panasonic DMC-LX5 | Nikon FieldScope III | 30XWA | hand-held (no adapter).
Reference:
James, J. Dale and Jonathan E. Thompson. 2001. Black-bellied Whistling-Duck (Dendrocygna autumnalis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online:
doi:10.2173/bna.578