A group of New Jersey farmers have overseen a test flight for an infrared-sensing drone to measure the number of deer around their fields.

Peter Furey, executive director of the New Jersey Farm Bureau, says farmers involved in the test seek to graphically document deer on their farms.

"The drones fly between 200 and 400 feet above the ground. And the camera will be drawn to the thermal heat image created by the deer in the field. They show up on the photography as items that can be counted. What the drone does is facilitate the counting of deer," Furey said.

Furey said the drone deployment is the use of technology to make their point that there are just too many deer in the state.

Estimates from 2013 put the population of white-tailed deer in the state at about 110,000, or 14 deer per square mile, down from a high of more than 200,000 in 1995.

The population in Princeton before the hunting season in 2010 was estimated at 114 deer per square mile. In Hopewell Township in Mercer County, it was estimated at 54 per square mile.

The state Department of Environmental Protection has lengthened hunting seasons, increased hunting permits and raised limits on the number of deer that can be killed in order to control the population, which the agency considers "problematic." These efforts are stymied, however, by an increasing number of parks and private lands that ban or restrict hunting, the DEP said in a 2016 report.

"We are just going to seek to create a coalition of interested parties in trying to arrest the over-population," Furey said.

That means reaching out to law enforcement and insurance companies, who will be interested in the issue of deer on roads. Also affected: landscapers as well as public health and municipal officials.

Two drone test over flights were conducted in early October.