njlarsen
What dates in May will you be here? Are there certain birds you would like to target? Celery Fields are a great location, but only for certain birds. There are some specialty birds in this area, as well as Florida's only endemic bird, the Florida Scrub Jay.
Here are two lists I made of birds that are only typically found in Florida or the Southeast USA that may be targeted on your trip:
Florida / Southeast Specialties:
American White Pelican (spring, fall, winter)
Magnificent Frigatebird (sping, summer, fall)
Tricolored Heron
Reddish Egret
Snowy Egret
Little Blue Heron
Limpkin
White Ibis
Glossy Ibis (uncommon)
Roseate Spoonbill
Wood Stork
Short-tailed Hawk (spring, summer, fall, uncommon)
Purple Gallinule (spring, summer)
Clapper Rail
American Oystercatcher
Black Skimmer
Common Ground Dove
Eurasian Collared Dove
White-winged Dove (uncommon)
Nanday (Black-hooded) Parakeet
Monk Parakeet
Mangrove Cuckoo (sping, very rare)
Chuck-will's-widow (spring, summer)
Red-cockaded Woodpecker (rare and local)
Gray Kingbird (spring, summer, uncommon)
Brown-headed Nuthatch (uncommon)
Loggerhead Shrike
Black-Whiskered Vireo (spring, very rare)
Painted Bunting (spring, fall, winter) uncommon
Bachman's Sparror (spring, uncommon)
Boat-tailed Grackle
Wading Birds:
Great Blue Heron
Little Blue Heron
Tricolored Heron
Reddish Egret
Great Egret
Snowy Egret
Little Blue Heron
Cattle Egret
Black-crowned Night Heron
Yellow-crowned Night Heron
Green Heron
Least Bittern
American Bittern (winter)
White Ibis
Glossy Ibis
Roseate Spoonbill
Wood Stork
American Oystercatcher
There are many other birds in the area not listed. Also, early May is heavy migration so lots of the Warbler Species are passing through as well as other migrants while you will be here. Late May migration slows down, but still some migrants passing through.