Field Station Leader: Dr.
Michael L. Avery,
Supervisory Research Wildlife Biologist
Florida Field Station
2820 E. University Ave.
Gainesville, FL 32641
Phone: (352) 375-2229
Fax: (352) 377-5559
Primary emphasis is on identifying, evaluating, and developing methods to manage depredation, nuisance, and property damage problems associated with native birds such as vultures and crows, and non-native species such as feral pigs, Burmese pythons, black spiny-tailed iguanas, monk parakeets, and other invasive species. To do this, scientists conduct behavioral and physiological studies with captive wild animals at the Florida field station and carry out field trials in Florida, Virginia, Pennsylvania, South Carolina, and elsewhere. Research is conducted with the cooperation and support of Wildlife Services (WS) Operations, community organizations, private companies, and state and federal agencies.
The Gainesville facility was built in 1963 and has served as a bird and mammal research field station ever since. In June 1993, the Florida WS State Director’s Office moved from Tallahassee to the Gainesville office. The 26-acre site is located three miles east of the University of Florida. There is a main building holding offices and laboratories, and three roofed outdoor aviaries for maintaining and testing wild birds. In addition, there are eight 10 x 30 foot enclosures and two ½ acre flight pens where various trials can be conducted throughout the year under natural environmental conditions.
Current Research Areas
Movements and Roost Dispersal. Vultures roost communally at night with up to several hundred birds sharing the same structure or group of trees. Roost composition is not static, however, and birds often shift among several roost sites from one night to the next. Thus, for effective management of vulture populations, it is necessary to identify the locations of all major roosting sites within the area of interest and to document the movement patterns of the birds among roosts as well as their daily activity between the roost and their feeding sites.
The area in and around a military air base often harbors a healthy vulture population which often creates dangerous situations for pilots. While vultures are not the only threat to aviation safety, they are a major one and effective management of the vulture population will contribute substantially to lessening the risks to pilots. At Marine Corps Air Station Beaufort SC, NASA’s Kennedy Space Center, Key West Naval Air Station, and Eglin Air Force Base in Niceville FL, we are documenting short- and long-term vulture movements using satellite GPS transmitters and placing ID tags on their wings intended for reporting when observed. By quantifying vulture flight patterns, locating roost sites, and identifying other key resources used by the vulture population, we will be able to develop a management approach designed to reduce the risk of vulture–aircraft interactions.
To report sightings of tagged birds, click here
Population Dynamics. As vulture populations increase, so does the frequency of interactions with human activities which has generated the demand for improved methods of managing these burgeoning black vulture populations. Development of effective long-term management strategies requires an understanding of the target population, including age distribution, age at first breeding, etc. Such information is especially important because the species can live more than 20 years, and not every bird in the population has the same capacity to contribute to the growth of the population. Age structure data are crucial to the development of realistic models that can simulate population responses to various management alternatives, such as lethal control and reproductive inhibition. One promising means to obtain age structure data is the recent demonstration that accumulation of the chemical pentosidine (Ps) in bird skin is correlated to age in a variety of wild bird species. For black vultures, this method will potentially shed light on important questions such as age of first reproduction, life span in the wild, and survivorship. For such a long-lived bird there appears to be no other feasible method to obtain such information.
Reducing Impacts of Monk Parakeets to Electric Utility Facilities. The monk parakeet is an invasive species native to South America that has become established in Florida and several other states. The bird is unique among parrots in that it builds a nest of sticks instead of nesting in tree cavities. For reasons that are not known, parakeets often select electric utility facilities as sites to build their large, bulky nests. This behavior frequently results in power failures as nest materials and birds come into contact with conductors which creates short-circuits. In cooperation with electric utility companies, field station biologists are investigating methods to reduce nesting activity by monk parakeets on utility poles and electric substations. The research project includes development of diazacon as a safe, effective chemosterilant to reduce population levels.
Invasive Ctenosaurs on Gasparilla Island. The black spiny-tailed iguana (Ctenosaura similis) is native from southern Mexico through Central America. In Florida, black spiny-tailed iguanas were apparently first released about 30 years ago on Gasparilla Island, Lee County. They now occur throughout the island, in both Lee and Charlotte counties and also at several other locations in Florida. In addition to causing nuisance and damage problems for homeowners, black spiny-tailed iguanas are believed to threaten sensitive native flora and fauna, including gopher tortoises and ground-nesting shorebirds. Spiny-tailed iguanas commonly share gopher tortoise burrows and may displace burrow occupants. Through a community-funded project, in conjunction with WS trappers, we have examined over 8,000 iguanas collected from the island. We have documented that the trapping and removal effort has shifted the size structure of the ctenosaur population so that the number of reproductive animals is greatly diminished. We have documented ctenosaur predation on hatchling gopher tortoises. Because these invasive lizards possess very high reproductive potential, continued trapping and removal efforts will be necessary to maintain the population at an acceptable level.
Feral Hog Impacts to Sensitive Plant Communities. Rooting damage by feral pigs (Sus scrofa) in the southeastern United States is widely recognized by ecologists as a significant threat to botanical biodiversity. We are documenting feral pig rooting at 52 ecologically-sensitive plant sites (730 acres) at Avon Park Air Force Range (APAFR) in south-central Florida. Our study, part of an ongoing integrated approach to managing the pig population at APAFR, evaluates the spatial and temporal changes in feral pig rooting in conjunction with selective removal of feral pigs by professional trappers and recreational hunters. Using systematic site surveys to locate all pig rooting in each study site, we delineate each incidence of rooting using highly accurate GPS receivers. For each rooted area, we estimate the percentage of rooted substrate, categorize the severity, and estimate the relative age of the rooting activity. While preliminary, our findings suggest feral pig rooting maybe dictated by soil moisture differences as reflected by seasonal variation across the landscape in the sensitive plant communities. As we continue to document site-specific rooting behavior, we will be better able to anticipate such changes in pig behavior. This information in turn should contribute to targeted trapping and removal efforts aimed at protection of biodiversity hotspots.
Avian and Invasive Species Population Management*
Feral Swine Damage Control Strategies*
Managing Depredation and Nuisance Problems Caused by Vultures
*the official "Research Projects" that describes the primary focus of research performed at this NWRC field station. The Project Web pages, in turn, describe goals, objectives and accomplishments of the research.