Once the spoonbills regained a toehold in Florida Bay, their numbers climbed steadily until 1979, when they peaked at roughly 1,260 nests. They then began a precipitous decline. Wetlands throughout the Keys were ditched and drained to create new housing developments offering residents both direct waterfront and road access, wiping out roughly 80 percent of the birds’ foraging grounds. “The Keys were covered in so much dust, it looked like a fog bank,” Lorenz recalls being told by an U.S. Army Corps of Engineers scientist who was working in the area at the time.
The spoonbills responded to such unprecedented development by shifting to more northern nesting areas in Florida Bay. They might have hung on there, if not for the drastic changes in water management that followed, including upgrading the canal system to three times its former size and increasing the number of pump stations to support booming agriculture in southern Dade County.
Lorenz’s research helped reveal the extent to which the spoonbills’ needs were quickly becoming at odds with development and water management. For one, water depth plays an important role in spoonbill survival. When water levels drop very quickly, as they are supposed to do naturally in November and December, it signals to the spoonbills that it is time to start nesting. If all is well, 22 days after the birds lay their first egg the conditions will be ripe for foraging—fish will be concentrated in shallow waters, where spoonbill parents can quickly suck them up and return to the nest to feed their chicks.
Learn more about Roseate Spoonbills at RestoreFloridaBay.org.