The Carlisle Mosquito Online

Friday, January 29, 1999


A revised approach to count deer

The truth of the adage, "There's no such thing as a free lunch," will soon be brought home to a number of Carlisle inhabitants. Our alarmingly prolific deer are about to be treated to small caches of irresistible grains set out in 15 to 20 habitat locations about town. But, as might be anticipated, there's a catch!

Unbeknownst to the deer, there may one day be representatives of the human species lurking behind or in the branches of nearby trees, armed with sleep-producing dart guns. This scene marks the start of an effort by the Massachusetts Fisheries and Wildlife Department to get a reliable handle on the size of the deer population in outer suburbia.

According to project leader John MacDonald, the information gained from the program will be useful in future decision-making about the need for population control, among other issues. He notes that both residents' complaints and environmental concerns about overpopulation have escalated in recent years, leading the department to seek more accurate data.

The need for a better counting method was demonstrated in an experiment in which helicopters were used to spot and tranquilize the animals in open territory around Plymouth, Massachusetts. That study confirmed that witness estimates, as well as the department's own kill statistics, were wildly inaccurate. Since the helicopter chase did not prove effective in a heavy forest canopy like that found in Carlisle, department personnel settled on a different strategy for this area.

Over the past month, department specialists have selected bait sites on both state-owned and private property, after obtaining permission from owners. They are distributing their "goodies" between 3 and 5 p.m. each afternoon, so the deer will come to recognize a welcome pattern. Then, in the second week in February, the trap will be sprung. The animals will be targeted and sedated, and each "relaxed" creature outfitted with a radio collar. Helicopter personnel will later locate and follow the marked deer over a predetermined period. They can then calibrate the population figure, using an established ratio between the number of marked deer spotted and the number of collars installed.

Asked about risk to the animals, MacDonald said that the medication in use today carries a substantially reduced risk, but that an occasional allergic reaction cannot be ruled out.

1999 The Carlisle Mosquito