There are currently 25 adult female deer on Shelter Island and 16 adult females on North Haven fitted with VHF or GPS collars. These collars provide movement data so that deer movement and home ranges can be mapped and analyzed. Cornell research staff monitors the deer fitted with collars three times per week. A vehicle equipped with antennas, receiver, and other field equipment will be seen frequently during the day and night in the community. The GPS collars will enable us to obtain fine scale movement information of deer in relation to roads and 4-Poster devices. One may notice the difference in the collars simply by sight: VHF collars are white and GPS collars are black. Deer-vehicle collision information and vegetation surveys will also be examined to evaluate the impact of 4-Poster device placement on the community.
Photo: Peter Priolo
VHF (very high frequency; radio frequencies between 30 and 300 MHz) collars are one of the most common technologies used to track wildlife. The VHF collar emits a radio signal that can be picked up by a receiver. Using a directional antenna plugged into the receiver, deer can be located and movement can be tracked. When the directional antenna is pointed directly toward the deer (collar), a strong radio signal is received and as the antenna moves away, the signal weakens. VHF technology requires Cornell staff to actively collect movement data 3 days per week in order to collect and record deer movement data.
GPS (Global Positioning Systems) collars employ a more advanced technology and are now being widely used to track wildlife. Similar to GPS units used for recreation and marine and land navigation, these collars use satellites to obtain location information for each deer. The GPS collar receives a signal from a GPS satellite and uses this to determine the animal's location to within 5-15 meters. A computer is then used to communicate with each GPS collar to retreive movement data that are stored in the collar’s memory.