Loss of Habitat Spells Trouble for Kestrel

Disappearing sandhill habitat is impacting survival of the threatened southeastern American kestrel.

Researcher on ladder at kestrel next box
A researcher inspects the
contents of a kestrel nest box
at Gold Head Branch State Park.

An animal and its habitat are closely linked. If the landscape that an animal calls home begins to change or disappear, the species’ numbers will likely dwindle. That is the situation facing the threatened southeastern American kestrel, a nonmigratory falcon whose fortunes are tied to sandhill habitat. Sandhill habitat, made up of dry, sandy ridges dominated by an open longleaf pine forest and a ground cover of grasses and wildflowers, has largely disappeared. Much of what remains is fragmented and overgrown. This has spelled trouble for kestrels, which have long made their nests in longleaf pine snags (dead or decaying trees that remain standing) found in sandhills. FWRI Wildlife Research staff and partners set out in 2009 to learn more about the number of kestrels left in Florida and their habitat requirements in hopes of increasing their numbers.

To begin, researchers developed a standardized data collection system and a database to manage annual monitoring data. Project staff work with partners on public lands to repair and maintain nest boxes, install new ones, and monitor nesting activity during the breeding season. During spring and summer 2011, project staff and partners monitored more than 520 nest boxes in 15 counties. They found more than 40 percent of the nest boxes occupied.

To learn more about the birds’ habitat requirements, project staff collected and analyzed vegetation data from selected sandhill sites. Researchers discovered that kestrels preferred nest boxes on sites with an open tree canopy where grasses dominated the ground cover. Sandhills intermixed with open areas such as unimproved pastures were more likely to attract kestrels than large, unbroken patches of sandhills, likely because most sandhill pine forests are currently overgrown from fire suppression. Researchers are also gathering data on kestrel nesting success and productivity in the farmlands that have replaced some sandhills in the contemporary Florida landscape.

In conjunction with their research, project staff are educating land managers, birdwatchers, and other biologists about the plight of the southeastern American kestrel and its habitat with public talks and printed materials. They have also posted species information, along with photos and descriptions, on the FWC Web site.

As the project winds down in 2012, researchers will analyze the data they have gathered to establish population targets for kestrels on FWC Wildlife Management Areas and other public lands. Project staff are also working with other FWC staff to develop a statewide kestrel management plan that will include strategies for increasing the size of kestrel populations and creating greater connectivity among them.

Partners in this study include the Florida Forest Service, the Florida Park Service, and various local chapters of the National Audubon Society.

FWC Facts:
Pyrodinium bahamense, an HAB organism that blooms each summer in Tampa Bay and Indian River Lagoon, chemically lights up to glow in the dark. This is called bioluminescence.

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