One of the more important jobs performed by Maine’s deer research leader, Kyle Ravanna, in concert with state regional wildlife biologists, is the annual estimate of winter deer losses. Deer mortality may take place at the wintering deer yards and elsewhere in early spring as undernourished whitetails disburse in search of new forage.

If the deer biologists can nail down the winter deer kill, they can then “manage” the overall deer numbers by correspondingly increasing or decreasing the harvest quota for antlerless deer.

For many years, one of the most valuable tools in this regard has been the WSI, or Winter Severity Index. The WSI is a somewhat complex formula, as explained by Ravanna:

The index is an arithmetic combination of average snow depth divided by a critical snow depth value, average deer sinking depth divided by a critical sinking depth, and average temperature divided by a long-term average temperature. The index value by itself has no meaning other than to allow us to compare how severe one winter is to another; keep in mind that this severity is defined for how severe it is for deer…nothing else. The real value in the index comes when we use it to estimate over-winter mortality.

Put simply, the WSI is a way to gauge just how tough a winter it is for the deer, not for you and me. In an effort to further “tweak” the system and scientifically test the validity of the 40-year-old WSI yardstick, Ravanna and his team have been involved in what has to be an historic first for Maine whitetail herd management. This past winter the biologists conducted a deer trapping and tagging operation in Wildlife Management District 17. Using a variety of devices, including clover traps, rocket nets, drop nets and a dart gun, the biologists captured 50 female deer. At least 14 of the captured and released does are adorned with telemetry collars. Many others are sporting tags in their ears that include contact information for reaching Ravanna’s office.

Surprising to me was the fact that the biologists, according to Ravanna, were able to subdue the deer, install their tags or collars, and release them apparently unharmed. As you know, a whitetail deer is a nervous, high-energy animal that can be easily overstressed by human handling. As Ravanna explains it, the tagging process can be done quickly and this deer trapping program hardly equates with holding the animal in captivity. The state deer scientists did concede that one animal was lost in the process.

Ravanna has been able to track the 14 collared deer via his computer and GPS technology. Surprising to even the biologists is the fact that it appears that all of the collared deer made it just fine through the Winter from Hell.

According to deer naturalist Dr. Leonard Lee Rue III, a healthy deer with a good layer of late fall fat can survive for 65 days in the deep winter without eating. The proviso, or course, is that the deer is not disbursed from the yard or over stressed by coyotes or other predators.

Although folks at MDIF&W have been keeping this story under the radar, Ravanna assured me that a fall press release will be forthcoming explaining the program to the public. Hunters who harvest a tagged or collared doe this fall are urged to contact Kyle’s office, using the contact information on the ear tag.

The author is editor of the Northwoods Sporting Journal. He is also a Maine Guide, co-host of a weekly radio program “Maine Outdoors.” His e-mail address is paul@sportingjournal.com . He has two books “A Maine Deer Hunter’s Logbook” and his latest, “Backtrack.”