Florida Scrub-Jay: Field Notes on a Vanishing Bird

Abstract

Not every natural area professional must consider an endemic, federally listed endangered species like the Florida scrub-jay (Aphelocoma coerulescens) when making land management decisions. But nearly all natural area professionals are confronted with stewardship challenges such as dealing with edge effects, invasive nonnative species, habitat fragmentation, successional changes, and management strategies with potentially adverse impacts on nontarget species. Mark Walters’s account of the rapidly declining Florida scrub-jay is a compelling case study of many of the land management and conservation issues confronting natural area professionals framed by a charismatic species with very strict habitat requirements. Florida scrub-jays are closely related to the widespread Woodhouse’s scrub-jay (A. woodhouseii), a species that occupies dry, brushy chaparral in the Southwest from Texas and Mexico northward to Oregon. About two million years ago, sea levels fell during the onset of the Pleistocene glacial advance and exposed sandy ridges along the northern Gulf Coast. These dry ridges allowed some western species including scrub-jays to migrate eastward and colonize what is now the Florida peninsula. When continental glacial ice melted, sea levels rose and isolated the scrub-jays and the other western species in Florida. Over thousands of years, these organisms evolved into new species adapted to the conditions on Florida’s high dunes and sand ridges. More recently, separate populations of scrub-jays became concentrated in four regions of the Florida peninsula. Because Florida’s well-drained uplands are the most valuable landscapes for cattle ranches, citrus groves, and housing, they have been targeted for development. Scrub-jays require exactly the same landscapes and, as a result, have suffered dramatic declines as scrub habitat has shrunk dramatically. Walters spent three years crisscrossing peninsular Florida, visiting each of the birds’ population centers. Walters is a veterinarian and a journalist but not a scrub-jay scientist, so local experts escorted him on driving and walking tours through the habitats. Detailed accounts of these guided explorations, presented as short chapters, constitute the majority of the book. Furthermore, because the challenges facing the birds’ survival differ somewhat depending on the region, Walters organized his book in four sections that allows him to focus on regional threats and conservation opportunities. The first section concentrates on mainland Brevard County and adjacent barrier islands along the central Atlantic coast. Walters’s grandfather lived in the county a century ago, where he was surrounded by scrub-jays as he drove the sandy coastal roads and fished on the barrier islands. Today, development has overwhelmed Brevard and scrub-jays persist on the mainland only in tiny, scattered preserves that are too small, too isolated, and too disturbed to sustain viable populations. In contrast, on South Merritt Island, the Kennedy Space Center and Merritt Island National Wildlife Refuge retain large portions of the original coastal dune scrub. As a result, scrub-jays thrive in these refugia. Despite their large numbers, though, the birds are threatened by inbreeding and declining genetic diversity because scrub-jays do not disperse readily over long distances—especially across inimical habitat—so there are few if any additions to the Merritt Island population. In addition, this isolated population faces loss of habitat from sea level rise and could be eliminated altogether if the island were to receive a direct hit from a destructive hurricane. Even more subtle changes threaten the birds. Scrub is an early successional habitat that historically was maintained through periodic fires. Because of the proximity of the Kennedy Space Center, prescribed burning is circumscribed and often prohibited outright, so land managers are constrained in their ability to maintain the habitat the birds require. On the Gulf Coast in Manatee and Sarasota counties, the birds’ plight is similar. Coastal areas used to support large populations, but housing and golf course development eliminated nearly all scrub near the Gulf beaches, and continuing infill development and encroachments likely have doomed the few scrub-jay family groups that remain in degraded natural areas. Inland from the hyper-developed coast, though, Manatee County has proactively expanded two open space preserves in cooperation with one of Florida’s phosphate ore surface mining companies. Through prescribed burning and mechanical vegetation removal, county land managers are gradually restoring scrub habitat in these extensive preserves. In addition, the phosphate mining company is paying to capture scrub-jays