Capture and Monitoring
FWC each year needs to capture a representative sample of the panther population for research and monitoring purposes. Safely capturing a Florida panther requires a well-coordinated effort involving wildlife biologists and trained dogs led by a highly skilled houndsman. While biologists look for visual clues such as fresh panther tracks, the dogs are using their remarkable sense of smell to find where a panther walked. A dog’s sense of smell is at least 10,000 times more sensitive than a human’s sense of smell. Dogs can even detect when crossing a panther’s trail whether the panther was walking to the right or left by the relative concentration of scent. The dogs follow the scent trail until they catch up to the panther. The panther typically is pursued for only a few minutes before it decides to retreat and climb up a tree to safety.
Once the panther is treed, biologists assess conditions to determine if the panther can be safely captured. If conditions are favorable, a portable air cushion and a net are put into place to protect the panther when it falls from the tree while under anesthesia. Biologists then use an air-powered gun to dart the panther with a sedative and wait for it to fall asleep. Often the panther falls from the tree, safely landing on the cushion below. If not, and the panther gets lodged in the tree, a biologist will climb the tree, tie a rope around the panther and lower it safely to the ground.
After the panther is stabilized, the team quickly goes to work collecting samples and data. Biological samples are collected, including blood for health screening, skin biopsies, plucked hair for genetic analysis and shaved hair for mercury monitoring. These samples help biologists and veterinarians assess the panther’s general health and monitor for potential disease threats. Captured panthers also are vaccinated against a host of diseases including feline leukemia virus, and given a deworming agent.
The panther’s identification number is tattooed in each ear and a passive integrated transponder (also known as PIT tag) is inserted under the skin for identification purposes. Finally, a radiocollar with a unique frequency is attached in order to track and monitor this individual panther’s movements. When the team is finished processing the panther, it is placed in a shaded area to recover while the team quietly leaves the area.
FWC biologists use several tools to monitor individual Florida panthers, including remote cameras and tracking collars that contain GPS (Global Positioning System) and/or VHF (Very High Frequency) transmitter components. Collars enable biologists to study panther habitat and space use, movement, and survival. They are sized and fitted to panthers based on sex, age class, and individual traits to prioritize animal safety. FWC follows the American Society of Mammalogists guidelines for transmitter weight, that the collar be less than 5% of the animal's body weight so as not to inhibit normal movement or behavior.
GPS collars are programmed to collect location data at defined intervals and save them to internal memory. Some models also transmit data via satellite to secure servers, which biologists can access from a computer. Performance and accuracy depend on factors including vegetation, terrain, atmospheric conditions, and animal behavior. Like VHF collars, GPS collars contain a radio beacon and can be located in the field by biologists as described below.
VHF collars have fewer electronics and cannot automatically collect or send location data. A location must be obtained in the field by using an antenna and radio receiver to determine the direction and relative distance of the signal emitted by the collar’s radio beacon. This can be done from the ground or low-flying aircraft. Methods of estimating location include homing in on a signal and “triangulating” by recording directional bearings from three different angles and mapping the area of overlap.
GPS collars provide fine-scale data at regular intervals with remote access, but they are more expensive and typically have a shorter battery life than VHF collars. VHF collars allow longer-term monitoring due to increased battery life, but data collection requires field effort and does not provide frequent locations or a measure of accuracy. While suitable for certain purposes like locating panther dens and studying survival, VHF collar data are generally not appropriate for use in advanced analyses of habitat or movement.