Mt. Lebanon deer survey results inconsistent

Published May 29, 2014 at 1:42 pm (Updated May 29, 2014 at 1:42 pm)

How many deer live in Mt. Lebanon? The number has serious implications for the municipality’s deer management strategy – particularly whether the population needs to be culled to reduce vehicle accidents and other resident complaints.

Unfortunately, the answer isn’t as straightforward as one might think.

In 2013, an aerial survey counted 342 deer. A year later, a similar survey counted only 196 deer.

Merlin Benner, president of Wildlife Specialists, addressed the discrepancy via conference call at the May 27 commission meeting. Benner is a Certified Wildlife Biologist. His firm assists clients with wildlife assessment, planning and monitoring.

According to Benner, the most likely explanation for the different survey numbers is that the deer simply moved temporarily – especially given the severe winter in 2014.

“We’ve done repeated surveys on specific areas within a few days,” he said. “We’ve had deer movements such that they were in a totally different area from one day to the next. Some deer could be on adjacent properties. Deer could have moved beyond the boundaries of Mt. Lebanon.”

Benner said in Maine, he documented some deer moving more than 40 miles.

He described aerial surveys as “state of the art,” adding that the only way to get more consistent results would be a “mark and capture” type of study. In those studies, deer are caught, tagged, released and tracked to get a more accurate picture of their travels. Benner emphasized that these studies are significantly more expensive and time consuming than aerial surveys.

Commission president Kristen Linfante asked him point blank which deer number Mt. Lebanon should consider.

“I would base decisions off the data most closely related to your issues,” Benner replied, “especially since the results of these two surveys don’t seem to fit other data you have. For some reason – you may never know it – fewer deer were observed in 2014 and that may not be reflective of the actual population.”

Benner said many townships use multiple data points to monitor deer populations. These can include police reports, reports to local administrators and data from insurance companies. Officials then make deer management decisions based on trends across all of this data. “You don’t have a bunch of scientists out there recording data in the same, repeatable way, so there’s a lot of error,” he said.

Linfante also raised questions over the effectiveness of sterilization as a deer management option, if the deer are in fact moving so much. “Would we just be sterilizing deer for other communities?” she asked.

Benner replied that sterilization is expensive and unlikely to work without a closed deer population. He added that he believed sterilization kills a significant number of deer due to the stress placed on the animals during capture and surgery.

Commissioner Kelly Fraasch disputed any elevated mortality rates (she said research actually showed low mortality rates), but agreed as to the high cost associated with sterilization: about $1,000 per animal.

“I think you should consider all deer management options, make an informed decision and show the reasons why you made that decision,” Benner said. “My opinion is certainly that sterilization costs a lot of money per deer. It seems like that would be very expensive.”

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