Moose in New Hampshire

The current plan, as approved by the general public, includes the Department’s suggested regional moose cut-off threshold population levels, which would result in the suspension of permit issuance for that region. Permits would be re-issued in that region once the population realized a two-year increase, resulting in a population density at least 13% higher than the cut-off threshold. Increased knowledge of how our changing climate and increasing parasite burdens influence the ability of the environment to maintain moose may cause revised recommendations for both the regional goals and cut-off thresholds.

We will break the state into two separate areas for this discussion:

Southern New Hampshire: The southern half of the state is composed of the Central, South West and South East moose management regions. Moose in this area are likely being most impacted by brainworm mortality. Once moose become infected with this parasite, the mortality rate is virtually 100%. Rarely do animals survive. The infection rate is dependent on deer density and the density of land snails and slugs. We do not know what the current infection rate is, but given the consistent moose declines we’ve seen in all three regions, it is probably quite high. As Massachusetts continues to support a very small number of moose with similar densities of deer, we believe that eventually our southern moose populations may also stabilize at low numbers, especially as the goals for deer in most of this area are to stabilize the deer populations at their current levels. We have set the cut-off thresholds in the Central and South West regions at a level very close to the population goals, so any further decline will result in permit suspension being implemented. However, suspending permit issuance will not stop the decline if brainworm persists at its current infection rate. The harvest mortality in this region is less than 1% of the population, while the overall mortality has to be greater than 20% to cause the recent declines. So, suspending permit issuance here will have no appreciable impact on the ability of this moose population to either increase or decline.
 

Northern New Hampshire: In the northern portion of the state, consisting of the Connecticut Lakes, North and White Mountain moose management regions, the growth of the moose population is being most impacted by the winter tick. The current season would take slightly more than 1% of the moose population. For the population to decline, the combined mortality from all causes must be removing at least 18% of this population. Because so few moose are taken during the season, the hunt is not influencing the growth or decline of this population in any substantive way. So, again, if we suspended permit issuance here, the moose population would not rebound. We are simply taking too few moose to have any impact. If we suddenly had three to five years of long winters, ticks would decline and the moose population would grow. However, winters are consistently shorter now, and the reality is that ticks will be the deciding factor in determining moose density on the landscape for the foreseeable future.

The moose population level is monitored annually using sightings by deer hunters. This method was tested for accuracy using aerial infrared thermal imagery. This independent method of moose sighting validated the ability of deer hunter sighting rates to accurately measure change in the moose population, and also gave us an equation that allows us to estimate moose density from the deer hunter-derived moose sighting rate. Recent work done in Vermont has shown that the deer hunter sighting rate tends to underestimate moose density, when compared to a population estimate based on an aerial infrared survey. Additional information on the age and physical condition of New Hampshire’s moose is derived from samples collected at mandatory check stations during the hunt.

The biggest problems facing New Hampshire’s moose are: 1) Climate change causing shorter winters and increasing winter tick loads; 2) Habitat loss and lack of habitat connectivity due to development; 3) Increasing deer densities, leading to increasing brainworm induced mortality for moose; 4) Reduced forage caused by lack of young forests. How can you help?

1. Become informed on how climate change is already changing our state. The Sustainability Institute at UNH has two publications on how New Hampshire’s climate has changed. There are many websites that contain good information on how to reduce your carbon footprint.
2. Support local and regional land conservation groups. Work within your town to conserve open space. Support town planning that includes open space.
3. Advocate for balancing deer and moose population at levels consistent with maintaining both of these species for the future benefit and enjoyment of New Hampshire’s residents. Attend Fish and Game season-setting and planning meetings.
4. Support young forests and read about the young forests initiative.

Moose are not currently a threatened or endangered species in New Hampshire. In the past two to three years, the moose population has grown or stabilized over much of the state. Our moose do face threats, which are outlined in New Hampshire’s Wildlife Action Plan. It is important that anyone reviewing the Wildlife Action Plan read the threats and actions PDF Document section (in Appendix A of the plan) for each species or habitat listed.  The threats are the reasons for the listing. The threats for moose include: (1) habitat loss and fragmentation due to development and lack of clear cutting; (2) the possibility that heat stress may impact body condition and reduce productivity; (3) increased mortality and decreased productivity due to increases in winter tick; (4) increases in mortality due to increasing deer densities causing higher brainworm parasitism; (5) mortality from motor vehicles.

If the listed threats continue unabated, there is concern that moose populations will irreversibly decline. The threats for which we are most concerned are those that impact habitat (development and lack of cutting) and those that increase parasitism (shorter winters). If these changes continue, the existing habitat will simply be unable to support moose.

There are three other hunted species, (grouse, woodcock and black duck) and many fished species that are also included on the list of Species of Greatest Conservation Need. None of these species, including moose, are listed due to concerns caused by hunting or fishing pressure. For moose, the concern is if habitat impacts and climate changes continue unchecked, it will result in an environment that is no longer capable of supporting moose. The other hunted species on the Species of Greatest Conservation Need list are also there primarily due to climate change and/or habitat-related concerns.

Every ten years, NH Fish and Game, with the help of the general public, develops a ten year Game Management Plan PDF Document providing goals and objectives to guide management recommendations. The most current plan was implemented in 2016 and will run until 2025. The following graphs depict the regional moose population changes since 1993, as well as the current status. Each graph shows the estimated moose density over time (white line); the changing goals (red line) for the density, as set every ten years during the planning process; and the cut-off threshold (green line). This cut-off threshold was first implemented during the 2016 planning process, due to our concerns regarding habitat change and increasing impacts from parasitism. If the regional moose population should fall to the cut-off threshold density, permit issuance in that region will be suspended. View the NH Game Management Plan PDF Document
 

The current New Hampshire moose population is approximately 3,000-4,000 animals. Regional densities range from 1.73 – 0.11 moose/mi2. These densities are typical for hunted North American moose populations, with 0.11 being on the low end of the spectrum and 1.73 being in the middle. The majority of moose populations in North America have a density of less than 2.5 moose/mi2, although some local populations far exceed this level.

While we know that winter ticks are a problem for moose in the northern portion of the state, we don’t know what set of circumstances (namely what weather conditions and moose density) may result in ticks causing an irreversible moose population decline or, conversely, what may allow moose to remain, and if so, at what level. Given changes in climate, habitat and parasite loads, remaining moose populations will not be able to be sustained at historic levels.

Seventy-five percent of the cost of the moose research is covered by federal funds derived from a federal tax on firearms and ammunition sales dedicated to the conservation and management of wild birds and mammals and their habitat through the Wildlife Restoration Program. These monies are made available to all state wildlife agencies and can be used for approved grant projects as long as the agency provides 25% in matching funds. The 25% state matching funds for our moose research are being provided to the Department by the University of New Hampshire, and are monies associated with faculty and graduate student time. Without these monies, NH Fish and Game could not afford to conduct this important research.

The best ways to reduce the impacts of winter ticks would be to add back the three weeks of winter we have lost due to climate change, or reduce moose density. That said, we don’t know, given the current weather parameters, what moose density may be most effective for balancing the reduction of tick impacts, while maintaining a viable moose population. Barring the longer winters or fewer moose scenarios, there is no viable way to reduce ticks on the landscape.

The best way to reduce brainworm mortality for moose is to maintain low deer densities. The current recommendation is to maintain deer densities lower than 10 – 13 mi2.