The Florida Keys Hawkwatch is dedicated to promoting the appreciation and conservation of birds of prey by committing to the long-term study of their migration through the Florida Keys.
Raptor migration studies have been conducted in the Middle Keys for nearly a quarter century, and a number of individuals, projects and organizations have played an important role in furthering the knowledge of birds of prey following the Florida Keys migratory flyway.
The term “raptor” is commonly given to diurnal birds of prey, such as eagles, hawks and falcons. Of the 26 raptor species recorded in the state of Florida (5 still under review by the Florida Ornithological Society Records Committee), 19 have been documented from the Florida Keys. Fifteen of these species are regularly monitored during fall migration at the Florida Keys Hawkwatch (FKH), in Curry Hammock State Park, near Marathon.
Most raptors migrate seasonally during spring and fall. A prominent drive for this behavior is the seasonal change in food base. Raptor migration occurs primarily by day, mainly as movement between latitudes, during which birds may cover long distances from “north” to “south” and vice versa.
Unlike waterfowl or passerines, most raptor species migrate singly, using a number of migratory flyways that are not necessarily the same during spring and fall. Raptors must save energy during migration in order to cover long distances; this can be achieved by using up-rising air currents, so-called thermals generated by sun-heated land surfaces. The Florida Keys are only a few inches above water, straddled between the Atlantic Ocean and Florida Bay – a flat ridge of limestone outcroppings curving towards the southwest, into the tropics. Although raptors regularly use updrafts – winds rising from hills or mountain slopes – to save energy, this is not the case anywhere in the Keys.
Over the Keys, raptors soar within columns of up-rising air currents. Height is continuously gained until the rising column cools down with altitude, and the birds must glide down to another newly formed column and start gaining height again. This way, a bird may cover up to 600 km (373 miles) per day. Because of this flight strategy and the fact that water surfaces do not generate rising air currents, most raptors avoid flying across water stretches wider than 25 km (15.5 miles). Following the narrow chain of the Keys, raptors have only a sliver of thermal-generating surface between two bodies of water.
Because of a considerable narrowing of landmass in the Middle Keys and a lack or alternate routes southward, the flight path of migratory birds of prey tends to be most concentrated there. Curry Hammock State Park was strategically selected as the location for the monitoring of raptor migration because of this factor. The Middle Keys tend to be no more than 1 km (0.62 mile) wide surrounding the FKH location, and offer a great vantage for the observation of birds of prey up to 2.5 km (1.6 miles) in distance.
Boot & Grassy Key Studies
The Middle Keys were first studied starting 1989, when single-day raptor migration counts were organized in Boot Key during October. Wayne Hoffman – ornithologist, then with National Audubon Society – coordinated the event over several years at the private key (currently closed to the public) about 7.2 km (4.5 miles) southeast of the FKH monitoring site. The single-day count of 1,820 migratory birds of prey in 1991 and 1,003 birds the following year brought the Middle Keys to broad attention.
Following that study, full-season censuses at Grassy Key (adjacent to Little Crawl Key, the location of Curry Hammock State Park and FKH) and roost surveys at Boot Key were conducted during 1996 and 1997 by Cindy Brashear, graduate student at Florida International University, and Philip Stoddard. Their study (2001) demonstrated that the Florida Keys were a significant migratory hotspot for 8 raptor species, whose season totals were equal or higher than the respective totals at recognized migrations sites elsewhere in North America. Capturing most attention, their study revealed that more Peregrine Falcons (Falco peregrinus) were observed during a season at the Middle Keys than had previously been counted at any other raptor monitoring site in the continent.
A photo from October 1991, during National Audubon’s Boot Key hawk count. Wayne Hoffman is in the blue shirt, R.J. Sawicki is the watcher on the right. Florida Keys Hawkwatch Archives. This was a fantastic 129 Peregrine Falcon day, not to mention the 993 Sharp-shinned Hawks!
The Florida Keys Raptor Migration Project
Starting the fall of 1999, HawkWatch International carried out full-season counts of migratory birds of prey at Curry Hammock State Park. This count site was designated to document long-term trends in Peregrine Falcon populations as well as population trends for the 7 other common diurnal raptor species observed in the Florida Keys (Lott 2006). These systematic counts were organized and coordinated by Casey Lott for HawkWatch International from 1999 to 2008, resulting in the first 10-year raptor migration dataset for the state of Florida, establishing the southernmost long-term monitoring site for birds of prey in the U.S. Several significant findings were championed at this site, primarily regarding the assessment of Peregrine Falcon population trends along the Florida Keys flyway.
The Peregrine Falcon experienced dramatic declines in North America during the period following World War II as a result of overt use of organochloride pesticides throughout the continent. It was listed as an endangered species in the 1970 Federal Register. As a result of a continent-wide effort, the recovery of the Peregrine Falcon became one of the greatest conservation stories in U.S. history. The species was removed from the Federal List of Endangered and Threatened Wildlife and Plants due to recovery in 1999. Ten years later, the species was removed from Florida’s list of imperiled species. As required by the Endangered Species Act, a plan was developed to monitor Peregrine Falcons 5 times at 3-year intervals beginning 2003 and ending in 2015.
Sites such as the monitoring station at Curry Hammock have been and will continue to provide critical data to the ongoing Peregrine Falcon population assessment. Along with a raptor monitoring site in the Guana Reserve, near Jacksonville, the Florida Keys Hawkwatch remains one of only 2 sites in the entire peninsula that provides seasonal censuses of migrating raptors.
The 10-year period under HawkWatch International helped establish the Florida Keys Hawkwatch as the highest Peregrine Falcon season in the U. S., (2858 in 2003) and the highest daily Peregrine count in the world, with 638 birds on October 11, 2008. Additionally, from 1998 to 2003, the organization conducted a banding station within the same state park, hoping to shed light on the origins and destinations of the raptors migrating through the Keys. In parallel, an array of environmental education programs were made available to the Keys community from 1999 to 2004. All these components formed part of what was known as the Florida Keys Raptor Migration Project. HawkWatch International ceased involvement with the monitoring of raptors in the Keys at the close of the 2008 fall season.
A New Coalition Going Forward
The hawkwatch fell into a dormant state following 2008, as previous organizing bodies redirected their efforts and funding elsewhere. Unfortunately, no count was conducted in 2009. Under the danger of falling in too great a gap that might have rendered the prior ten-year period ineffective, an effort was commenced by the Hawk Migration Association of North America (HMANA), with the assistance of Hawk Mountain Sanctuary, to reestablish the Florida Keys Hawkwatch as an all-volunteer site during 2010. Julie Brown and Ernesto Ruelas Inzunza of HMANA have been greatly instructive in reestablishing the site.
The 2010 season resulted in a successful transition, and although the site was staffed for a shorter period than the historic seasonal length, a committed group of individuals and organizations came together to participate in the revival of the project. Tropical Audubon Society (South Miami) took a leading role in organizing volunteers under the coordination of board member Rafael A. Gálvez.
To ensure that no future fall migration season goes unmonitored at the Curry Hammock site, the project has been reorganized and redefined as a “locally-owned” operation committed to the long-term sustainability of a raptor migration site, rebranded as the Florida Keys Hawkwatch, under the auspices of Tropical Audubon Society (TAS). A coalition of regional and national organizations has rallied in support of the project in preparation of the upcoming 2011 fall migration season, which is being organized by Rafael Gálvez as a representative of TAS.
Additional support for the 2011 season has been granted by Jim Eager and Space Coast Audubon Society, Mark Hedden and Florida Keys Audubon Society, the Helen G. & Allan D. Cruickshank Research Award through Florida Ornithological Society, Jim Bell and Florida Keys Birding & Wildlife Festival, and Jeff Bouton with Leica Sports Optics.
The 2010 season operated under the notion of “big shoes to fill” after the successes of the prior 10-year period. A number of individuals and organization made the challenging transition possible: Julie Brown, Ernesto Ruelas, Rafael Gálvez, Jim Eager, Karen Dyer, Katie Lyons, Andy Prothero, John Haire, Rudy Brancel, and all the folks that visited and participated at the site. Audubon of Florida’s Tavernier Science Center and their staff, primarily Jerry Lorenz and Peter Frezza remain great allies of the Florida Keys Hawkwatch – their continual support is greatly appreciated.
Many other individuals should be continually thanked for laying down the foundation for this important monitoring site, primarily Casey A. Lott, who dedicated 10 years of his life to the Florida Keys Raptor Migration Project – his great efforts are not forgotten.
For a more complete list of past acknowledgements, please refer to the following publication: Lott, C. A. 2006. Systematic monitoring of peregrine falcons and seven other diurnal migrant raptor species in the Florida Keys. Final report. Florida Fish and Wildlife Conservation Commission, Tallahassee, Florida, USA.