Using Sound Science to Help Manage Wildlife Resources
In an ongoing effort to understand the current status of wildlife, their habitats, and public concerns and expectations, the Division of Fish, Wildlife and Marine Resources continued its many research initiatives in 2011. Successful long-term management of wildlife populations requires knowledge attained through rigorous science. The Division and its many partners in conservation are committed to research that helps us understand and develop solutions for the problems faced by wildlife.
The following paragraphs highlight a few of the wildlife research projects currently underway.
Black Bear Ecology and Population Estimates in an Expanding Bear Population
Black bear populations are thriving in New York State, having increased in number and distribution throughout the southern tier. Bears are now more frequently seen in areas with higher human populations and agriculture, resulting in increased human-bear conflicts. To better understand bear ecology as populations expand, DEC has partnered with the New York State Cooperative Fish and Wildlife Research Unit on two projects in south-central New York.
Bear Habitat and Space Use: Data from GPS-collared bears will be used to determine how movements are defining home ranges in both core areas and recently expanded bear ranges. Additionally, we will evaluate habitat selection and temporal variation in space use between bears in the core and the expanded range.
Bear Population Density: To estimate black bear density, we will conduct a non-invasive, genetic-mark recapture study to collect black bear hair samples from barbed-wire snares. Additionally, this study will analyze landscape genetics, potentially identifying features facilitating and/or inhibiting black bear gene flow.
Impact of Wild Food Abundance on Black Bear Ecology and Nuisance Behavior
Why do some summers in the Adirondack Park have more human-black bear conflicts than others? Is nuisance-bear activity related to the crop cycle of beechnuts, their main source of fat? Do black bear sows synchronize cub production with the beechnut cycle? To better understand and predict bear behavior, DEC has partnered with researchers at SUNY-ESF to analyze data, tracking natural food abundance in the central Adirondacks in combination with annual records of bear harvest and human-bear conflict levels. Preliminary findings indicate that:
- Abundance of summer foods (e.g., red raspberry) tends to fluctuate in unison with cycles of beechnut production and may act as the catalyst for fluctuating levels of nuisance-bear activity.
- More bear cubs are born in winters following an abundant beechnut crop.
- Black bear take by hunters tends to increase during the early season in years with abundant soft mast (e.g., berries and fruit) and also increases during the regular season when beechnuts are widely available.
Common Merganser Feeding Habits
Since the 1980s, common mergansers have expanded their breeding range across southern and western New York. Because they are fish-eating birds, mergansers may be preying on hatchery-reared brown trout that DEC stocks in many streams to enhance recreational fishing opportunities. Therefore, DEC has partnered with SUNY-ESF to assess the potential impact of common mergansers on trout stocked in the west branch of the Delaware River in Delaware County. To study the abundance, movements and diet of these birds, we captured and banded 87 common mergansers during the past three springs. In 2011, 12 male mergansers were tagged with special satellite transmitters to track their movements during spring, summer and early fall. Results of this study will help determine whether mergansers are taking significant numbers of stocked trout and, if necessary, will help DEC staff identify ways to reduce the impact in areas with high merganser populations. The study will also provide new information on migration habits of mergansers and their exposure to environmental contaminants. This study is expected to be completed by December 2011.
Wild Turkey Fall Harvest Potential
In fall 2010, DEC partnered with the National Wild Turkey Federation and SUNY-ESF to investigate the wild turkey harvest potential of landscapes within New York State. Important factors that affect turkeys in New York include spring weather effects on reproductive success, winter weather effects on survival, effects of landscape configuration on reproduction and survival and hunter harvest rates, especially during fall when hens may be legally taken.
New York State currently has six fall turkey hunting zones. Each zone has a distinct combination of season length (1–7 weeks) and bag limit (1–2 per day and season), but each may also include ecological units that have very different turkey harvest potential. With advances in GIS, much new information on turkey populations (e.g., productivity, harvest and survival rates) and continued high demand for turkey hunting opportunity, a more ecologically based delineation of turkey harvest zones is warranted. This project will help determine the best spatial scale for wild-turkey management and enable us to delineate season zones based on key ecological factors. This will help us provide as much harvest opportunity as possible, while ensuring sustainable use of the wild turkey resource.
Status and Distribution of River Otter
River otter populations are managed via harvest data in about one-third of the state. In the remaining two-thirds, harvest is not allowed, and the status of otter populations is unknown. This area includes “zones” where harvest was restricted about 10 years ago and a larger area where an otter reintroduction effort was conducted in the late 1990s. In 2010, DEC partnered with SUNY-ESF to develop harvest-independent survey methods for monitoring unharvested otter populations. Intensive sign surveys were completed in winter 2011 in the St. Lawrence River Valley (an area with dense otter populations that may be trapped) and the Mohawk River Valley (a low-density area where harvest was restricted). Completion of this study is expected in December 2011.
Population Status of Eastern Coyotes
How many coyotes live in New York State? According to researchers at SUNY ESF, about 33,500. This number is the result of a rigorous research project led by graduate student Sara Hansen from SUNY ESF. Sara led a team of nine technicians who broadcast howls throughout the night and all over the state during July-August 2010 to count the coyotes that howled back. This novel research linked traditional call-response surveys with modern “distance sampling” techniques, where the distance to a calling coyote provided the key to correcting for coyotes missed during the survey. Sara’s team recorded from 1-6 coyotes during a given survey, with the average group size being 2 adult coyotes. Coyotes were encountered by Sara’s team in only 24% of 541 surveys, and previous research shows an average response rate of 36% for resident coyotes. After accounting for the non-responding individuals, the estimated density of coyotes ranged from 6.8 coyotes/10 square miles in the Adirondacks and Southern Tier to closer to 16.6 coyotes/10 square miles in the Mohawk and St. Lawrence river valleys. Coyote densities in New York State are on par with reports elsewhere in the eastern U.S., and represent the peak size of the resident coyote population (early August) which will decline through fall and winter as individuals disperse and the trapping and hunting seasons commence.