Probably nothing to do with climate change. Audubon article:
In the early 1800s, people who visited coastal areas in southern Florida in winter were met with an astounding sight: hundreds of thousands of American Flamingos. The majestic pink bird, endemic to Central and South America and the Caribbean, wintered in Florida’s tropical climes. By the end of the century, however, European settlers seemed to have eradicated the leggy waders through feather and egg harvesting, and ever since the birds have been scarce in the Sunshine State—until recently.