Courtesy of the Wildlife Management Institute

image of USGS Cooperative Research Units logoimage of North American moose, Credit: Dave WattlesThe North American moose (Alces alces) is the largest member of the deer family (Cervidae) and is distributed throughout northern North America. Along the southern edge of their range, moose can be found in the parts of the Pacific Northwest, down the Rocky Mountains, around the upper Great Lakes region, and into New England and New York. Moose habitat covers a wide array of vegetation types and environmental conditions, but two aspects characterize where moose live:  woody plants and cold temperatures. Up to 90 percent of moose diet is comprised of woody browse (twigs, buds, stems), and their large body size, thick coats, and long legs make them especially well adapted to some of the coldest temperatures and deepest snow on the continent.  Moose can be found throughout the boreal forest, mixed broadleaf-conifer forests, delta floodplains, tundra subalpine environments, and stream valley shrub communities.In the northeastern United States, moose were historically found as far south as northern Pennsylvania and New Jersey. During the colonial era, land clearing for agriculture and uncontrolled subsistence hunting pushed the moose population into northern New England. With farm abandonment and reforestation, and the institution of game management laws, moose populations expanded in northern New England and animals started to show up in southern New England during the mid- to late-1900s, after an absence of two to three centuries. Today, some 1,000-2,500 moose are thought to occupy Massachusetts and Connecticut. However, a dense human population, a highly developed landscape, a dearth of early successional stage forest, and warmer year-round temperatures compared to other parts of the geographic range are unique challenges to moose survival in this region.In 2006, the USGS Massachusetts Cooperative Fish and Wildlife Research Unit and the Massachusetts Division of Fisheries and Wildlife began studying moose. The first GPS collar to be used on any species of wildlife in Massachusetts was placed on a bull moose in Royalston, just south of the New Hampshire border.  Since then, over 30 GPS collars have been placed on bulls and cows in central and western Massachusetts, resulting in tens of thousands of locations and movement paths.Moose are using areas from 10-30 square miles, with the home ranges of males being larger than females. Moose spend most of their time in upland or higher elevation areas, possibly because the larger valleys have more human development, but also likely because the higher elevations are cooler and breezier. At least 50 percent of the time, moose can be found in young, vigorously growing forest where they find the large amounts of young woody browse that makes up most of their diet. However, thermal shelters (i.e., cover that can protect moose from heat) such as conifer stands and wooded wetlands, see significant amounts of use in all seasons, but particularly in spring, summer, and fall. We have documented a clear pattern of moose using more open habitats (e.g., harvested patches of forest) when temperatures are cooler and at night, and retreating to thermal shelters when temperatures are warmer, especially during mid-day.

Moose populations throughout much of North America are facing an uncertain future. Research from Minnesota, Michigan (Isle Royale), Montana, Wyoming, British Columbia, and Nova Scotia indicate widespread and sometimes precipitous declines in numbers, especially along the southern edge of the range. Most reports implicate an interaction between increased temperatures and diseases or parasites as the probable cause of the declines.

In southern New England, year-round temperatures are consistently warmer compared to elsewhere in North American moose range. However, there is strong evidence that the unique structure and composition of the habitat in southern New England allows moose to ameliorate the effects of high temperatures. Relatively low to moderate densities of deer (where moose and deer overlap) and low densities of moose also mitigate the impacts of diseases and parasites.

In general, numbers of moose in southern New England appear to be relatively stable or declining slightly, and there is no indication that there has been a precipitous drop in numbers. We attribute this to the widespread availability of thermal shelters, such as closed canopy forest and wooded wetlands, interspersed with small foraging patches, and to low densities of moose, which lessens susceptibility to parasites and disease.

Each month, the ONB features articles from Cooperative Fish and Wildlife Research Units across the country. Working with key cooperators, including WMI, Units are leading exciting, new wildlife research projects that we believe our readers will appreciate reading about.