The Science Behind the Seasons

By Kent Gustafson, Biometrician and Deer Project Leader, NH Fish and Game Department (posted March 2010)

Excerpt: "Of particular note is the fact that genetic research has come to light that confirms the potential negative impacts of a 2-point APR on the long-term characteristics of a deer herd."

Deer hunters are -- unsurprisingly -- curious about how Fish and Game makes decisions about the white-tailed deer hunt in New Hampshire. Proposals in the works for the 2010-2011 seasons include eliminating the antler point restriction up north, and decreasing either-sex days in many areas; below are some thoughts on those two hot topics from “behind the scenes.”

What Process Guides Changing the Rules?
Hunting rule changes come to pass through a specific process; here it is in a nutshell: the N.H. Fish and Game Department reviews hunting seasons every two years, and proposes changes to the seasons with the goals of a) keeping the state’s herd healthy; b) meeting the population goals established in the Big Game Management Plan (click here to view); and c) providing recreational opportunity. Fish and Game biologists draft preliminary proposals which are reviewed by the Commission, district law enforcement and other regional staff. Final proposals are settled on by a Wildlife Programs Committee, which are then presented to the Commission for their review, possible modification and approval. The 2010 proposals have been considered and modified by staff and the Commission, and they will be considered in statewide public hearings in early April, where hunters can ask questions about the proposals and offer their input. With public input in hand, the proposals will be finalized and presented to the Commission for final review and approval. The entire package is then sent to the state’s Joint Legislative Committee on Administrative Rules for their approval. It’s a complex process.

Antler Point Restrictions -- "Survival of the Smallest"
First things first: As guardians of the state’s wildlife resources, our primary concern is the health of the deer herd. Yes, hunters’ opinions are considered when we create rules and set seasons, but our overriding goal is to ensure that New Hampshire’s deer are healthy and exist in appropriate numbers for the habitat throughout the state.

In 2007, Fish and Game implemented a 2-point antler point restriction (“APR”) in Wildlife Management Unit A, the northernmost unit of the state. A Deer Management Task Force (with members from the hunting public, interested organizations, and Fish and Game) made the recommendation to institute the 2-point APR, reasoning that fewer yearlings would be killed, allowing more bucks to grow to adulthood and improve the “buck age class structure” in WMU-A.

The decision to implement a 2-point APR was somewhat contentious, due in part to concerns about the genetic consequences of protecting spike bucks while allowing the harvest of fork bucks. Other concerns at the time related to the possible illegal or accidental taking of spike bucks, as well as whether spike bucks could effectively be “stockpiled” for future “use” at ages 4.5 or 5.5+, given other mortality factors and increased hunting pressure on older bucks. In some instances, these concerns have been realized. Of particular note is the fact that genetic research has come to light that confirms the potential negative impacts of a 2-point APR on the long-term characteristics of a deer herd. You see, the goal of the 2-point APR was to reduce the taking of yearling bucks by protecting spikehorns. But in fact, many yearling bucks have antlers bearing 3 points or more. Therefore, when you harvest a buck with more than 2 points, you could in fact be killing a genetically superior yearling -- one that has managed to grow larger antlers in a limited time period. The authors of a long-range controlled study in Texas put it this way:

...Yearling spike-antlered deer are inferior to fork-antlered yearlings with regard to body weight and antler characteristics and will remain so in succeeding years; most deer which are spike-antlered as yearlings will not be spike-antlered in later years, but will continue to be inferior to their fork-antlered cohorts; and body weight and antler characteristics appear to be highly heritable characters.

Therefore, in the 2-point APR scenario, it’s “survival of the smallest.” The big-antlered yearlings get killed and the spikehorns go on to reproduce. Research indicates that it could take as few as 4 generations of offspring to see noticeably and consistently diminished antler size, irrespective of nutrition and timing of birth. Instead of protecting all yearling bucks, the 2-point APR results in selective culling of those yearlings with the best genetic potential!

What might this mean? In a short time period, the 2-point APR could alter the antler characteristics of the herd in the North Country -- changes from which the herd might not recover in our lifetime. It would be imprudent of us to allow this to happen, which is why Fish and Game has proposed to eliminate the 2-point APR in WMU-A for the 2010 deer season. Over the next year, Fish and Game will focus efforts on determining hunter desires and preferences regarding the New Hampshire deer herd, while working on proposals to achieve the desired results with minimal negative impacts. We could consider APRs with greater point values in the future, but it is important that we stop the 2-point APR right away, to protect the genetic integrity of our deer herd.
Either-sex Days
The tool that our wildlife managers use to manage population size around the state is “either-sex days.” How do they work? When you kill a doe, you eliminate the possibility that she will reproduce, thereby reducing fawn production and herd size. When you kill a buck, other bucks will willingly step in to fulfill his reproductive mission, so it has minimal impact on the number of future deer.

That is why either-sex days in New Hampshire are limited. Sure -- in WMUs where deer overpopulation is a problem or where the population is close to the objective, the seasons allow for more days of harvesting does, to help control the number of fawns that will be born the following year. But in WMUs where deer numbers need a boost, there may be few or no either-sex days at all, to protect the does and their future offspring in an effort to build the population.

Right now, deer numbers in many parts of the state are down from near record numbers in 2007; they are still recovering from unusually high winter kill over two rough winters, 2007-2008 and 2008-2009. Fish and Game has proposed a reduction in either-sex days in many of these areas, to protect female deer and in so doing, to help increase herd growth to desired levels. Once populations recover, the either-sex days will be liberalized to help stabilize deer numbers. The number of either-sex days fluctuates over time in order to pro-actively adjust harvests in response to winter severity. Some hunters think we’ve gone too far in any given year, others believe we haven’t gone far enough, but the bottom line is that we do what we can to strike a balance and help the herd recover -- while minimizing the risk of exceeding the population objectives.

Can we guarantee that each hunter will see “enough” deer to be satisfied? No. But we can guarantee that we use the best tools and science at our disposal in an effort to keep our regional deer populations at levels that are healthy for the herd and appropriate for the given habitat, so there will always be a healthy deer herd in New Hampshire, for our benefit, and for that of future generations.

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