Deer Management in Sligo Creek Park: Context, Status, and the Way Forward

Approved by the FOSC Board, Sept. 9, 2009

Executive Summary

The problem of deer overabundance in Sligo Creek Park is the first issue in the eight-year history of Friends of Sligo Creek that has proven divisive among its most active members. Montgomery County, Maryland, like many urban and suburban jurisdictions across the Eastern U. S., has similarly struggled with this issue. At a number of locations, the County has used managed hunts and sharpshooter programs to cull herds and reduce deer damage from vehicle collisions, landscape browsing, Lyme disease, and overgrazing of natural areas. Since 1998, the County has effectively reduced deer densities and damage and begun restoring forest health in its larger parks. Deer meat harvested through its sharpshooter programs is donated to needy food banks.

No deer control of any type has been tried in the Sligo Creek watershed. Despite successful control elsewhere, the lethal means of controlling deer damage remains controversial and has the potential for alienating some of the volunteers on whom we depend for the success of our many programs, including clean-up, storm-water control, water quality monitoring, and advocacy. For these reasons, the FOSC board is not now taking a formal position explicitly advocating for a deer culling program in Sligo Creek Park. Rather, the board will pursue five activities:

  1. Create educational materials on deer management for its website.
  2. Stay in contact with neighborhood associations that border the Park and provide them with guidance and input on deer issues (e.g., ecologically-informed perspectives and advice on effective ways to work with the County Parks Dept.).
  3. Cover deer issues regularly in FOSC’s monthly e-newsletter;
  4. Hold a program meeting with a County Parks staff member to discuss wildlife issues in the Park;
  5. Establish one or more additional deer exclosures in the Park to protect sensitive areas and gather more data on deer damage.


The Board of the Friends of Sligo Creek recognizes that damage created by an overabundance of white-tailed deer is occurring throughout the Eastern United States and that efforts to address this problem have been ongoing for more than fifteen years. The impetus for action region-wide has most often been concern over deer-vehicle collisions, Lyme disease, and damage to crops or landscape plants on private property. In a minority of cases, including Montgomery County, management plans have also been based on alleviating damage to natural areas. The “Comprehensive Management Plan for White-Tailed Deer in Montgomery County, Maryland” (1995) lists four objectives, one of which is to “reduce the negative impacts of deer on natural communities in order to preserve the natural diversity of flora and fauna within the county” (p. 4; see web resources below).


Most jurisdictions that have decided to deal with deer over-abundance have chosen lethal forms of culling — managed hunts and sharpshooting — to reduce local deer populations. This method has sometimes provoked protests and unsuccessful lawsuits from animal rights advocates. While a few jurisdictions continue to struggle over the issue of culling, sharpshooting and managed hunts have proceeded in spite of protests in the great majority of cases. The 1995 Montgomery County plan considered a variety of methods to reduce deer problems: trap and transfer, surgical sterilization, fertility control, re-introduced predators, fencing, repellents, supplemental deer feeding, controlled hunts, and sharp-shooting. Of these, the plan concludes that only can be “practical and effective in reducing deer numbers” on public parklands (p. 19): extended hunting limits and sharpshooter programs. Only the latter of these two might apply to Sligo Creek Park. (For a recent evaluation of deer management methods, see Northeast Deer Technical Committee under resources below.)

Donation of Harvested Meat

Often neglected in debates over deer culling is the value of deer meat donated to food banks and other charities. Between 1997 and 2000, the national program known as Farmers and Hunters Feeding the Hungry distributed more than 750 tons of meat to food shelters across the country (see Connecticut Dept. of Environmental Protection report, pp. 16-17, in resources below). In Maryland, this program has donated over 280 tons of meat since 1997, resulting in over 2.2 million meals being served to people in need. According to the Maryland Department of Natural Resources, “food banks tell us that meat is their least available food item due to the high cost . . . and that they gratefully accept venison donations. Venison is a nutritious, low fat, high protein meat that is distributed and/or cooked by hundreds of Maryland community organizations such as church pantries, Salvation Army, community food banks, church feeding ministries, emergency assistance programs, and children’s homes” (see MD-DNR web page on Farmers and Hunters Feeding the Hungry in resources below). When Montgomery County uses sharpshooters for culling deer, all of the meat is donated to food banks.

Task Force

Most jurisdictions in the eastern U. S. (state, county, local) have take the Citizen Task Force approach to addressing the problems of deer damage and the controversies inherent in addressing them. (For example, see New York Dept. of Environmental Protection, under resources below.) The Montgomery County Council created a Deer Task Force in 1993 to study the problem, evaluate options, and make recommendations. Based on the Task Force report, the County set up the Montgomery County Deer Management Work Group, consisting of representatives from the Maryland National Capital Park and Planning Commission, the Maryland Department of Natural Resources, and the Patuxent Wildlife Research Center of the U. S. Geological Survey. Since completing the 1995 County plan, the Work Group has expanded its membership to include representatives from the Montgomery County Cooperative Extension, the Montgomery County Police Department, the National Park Service, and the Washington Suburban Sanitary Commission. As part of its mandate, the Work Group issues annual reports, available on-line (see resources below).

Deer Density

In its survey of deer management in the county from 1996-2007, the Deer Management Work Group cites studies showing that deer densities should be “maintained at approximately 18-30 deer per square mile to allow for optimum forest regeneration and assure habitat for forest species” (p. 4; see resources below). Since sharpshooting and expanded hunts began in the county, deer densities have been reduced in many parks, e.g., from 142 to 28 per square mile in Little Bennett Park, from 220 to 31 in Northwest Branch Park, and from 75 to 15 in Wheaton Regional Park (p. 11).

For Sligo Creek, because it is so long and narrow, Parks staff stress that any count of deer reflects the number that utilize the park as part of their larger home ranges, rather than residing exclusively in the Park. Through its survey of Sligo Creek Park in March 2007 (using five 100-acre plots), Montgomery County Parks concluded there were 56-70 deer using the Park above Colesville Rd. (Rt. 29), with the lower number believed the more accurate. At the request of FOSC, Parks estimated (by adding in likely increase from fawning) that, in March 2008, there were approximately 75 deer using the same area. Through its survey in August 2008 (using six 100-acre plots), Parks concluded there were 80 and 112 deer using the area above Colesville Road, again with the lower number probably the more accurate.  Thus, a rough calculation indicates a growth rate between summer of ’07 and summer of ’08 of approximately 52 percent per year. A third survey was conducted in August 2009, which will provide more information on growth trends.

At the same time, the county’s Deer Management Work Group report points out that “different parks in the county serve different purposes” and that “conservation parks and other park areas designated as being of high natural value are the highest priority” for deer management (p. 4). The report concludes that “in park areas that serve other functions, such as recreation, or that are small and/or of generally lower natural quality, deer impacts are of less concern [and] therefore population management may not be a priority” (p. 4). This position has been re-stated by Park and Planning in its communications with FOSC representatives.

Deer Impact in Sligo

To help measure deer impact in Sligo Park, FOSC constructed in 2004 two 30′ x 30′ deer “exclosures,” fenced-in areas that allow for comparison of vegetation that is, and is not, exposed to deer browse. One is located in the Kemp Mill area, the other just below the Golf Course. Vegetation was monitored every year until 2009, but little difference was detected between inside and outside the fences. (The monitoring results will be posted on the FOSC web site.) It is possible that squirrels and other rodents capable of entering the exclosures are responsible for eating all the young plants. The inconclusive results from the these exclosures stand in contrast to results in the county’s larger parks, where such exclosures demonstrate dramatic differences inside and out (see photos in the Mont. Co. Deer Results 1996-2007, p. 8, or, even more dramatically, in the Connecticut report under resources below).

One dramatic exception in Sligo was a dense carpet of Mayapple observed inside one of the exclosures, with none observed on the outside. Most stewards for FOSC’s twelve sections report significant damage to understory vegetation by deer. Of greatest concern is the effect on tree saplings. In Sligo Park above University Boulevard, a dramatic “browse line” can be observed where deer have eaten most vegetation below eight feet (aside from mature trees and shrubs). One expert birder points out that the Kemp Mill part of the park has witnessed the disappearance of two ground-nesting birds over the last ten years, Ovenbird and Kentucky Warbler, a loss she attributes to deer damage (Gail MacKiernan, FOSC bird outing, 2008).

Options for Sligo

Culling by Parks: County Parks management told FOSC representatives during several discussions in Spring 2009 that, while they recognize that deer are a problem in Sligo, they will not consider sharpshooter culling in the park for the foreseeable future. Sligo is not scheduled for any deer management effort in the winter of 09-10 when annual culling will be held elsewhere in the county. In the county’s 2009 Deer Management Report (see resources below), the starting year for deer management in Sligo and seven other county parks is indicated as “future” (i.e., not “never,” p.11). The same report indicates the “recommended action” for Sligo as “investigate management for FY09.” No other control measures (e.g., fertility control) are considered practicable at this time. If sharpshooting is ever instituted, Parks has said that it will most likely be an option only upstream from Colesville Rd (Rt. 29). While the benefits of culling have been dramatic in nearby Wheaton Regional Park, the benefits in Sligo Park are not as certain due to the more ecologically degraded conditions in Sligo.

Pressure from citizen groups: Efforts by the FOSC president and others to assess public interest in deer management have been limited and informal. No neighborhood association or other local environmental group is actively opposed to culling of deer, but no group has gone on record in favor of it. A very few individuals have voiced opposition based on concern for animal welfare or human safety. Most watershed residents spoken with by the FOSC president view culling of deer as a necessary evil for the greater health of Sligo’s ecosystems. The level of public awareness on the issue of deer damage in the Washington area is clearly growing, thanks in large part to articles in the press.

The Way Forward

The deer issue is the first in the eight-year history of FOSC that has proven seriously divisive among those most active in the organization. The FOSC board will therefore proceed with caution as follows:

  1. Given (a) the divisive nature of deer management, (b) the importance of maintaining FOSC’s high reputation among watershed residents, and (c) the risk to its other programs were it to aggressively advocate for culling deer, the FOSC board will not adopt at this time a formal policy that advocates culling of deer in Sligo Creek Park.The FOSC board believes that local neighborhood associations within the watershed must be active partners in requesting a county Parks program of professional sharpshooters to reduce deer in those areas of the Park near their homes. FOSC leadership is eager to contribute to internal deliberations by neighborhood groups by providing reliable resources, speaking at meetings, and helping to arrange for experts to address their memberships. The FOSC board believes it cannot circumvent the neighborhoods by appealing directly to Parks to instigate a sharpshooter program in Park property so closely adjacent to their homes.
  2. FOSC will continue to work with the Parks Department and other Montgomery County officials on mitigating the problem of an over-population of deer. We will encourage them to look for viable, sound solutions that will be acceptable to neighboring communities. We will especially look for signs that Parks may reconsider their current view that culling is not appropriate at this time for Sligo Park. We expect to help educate residents of the watershed about deer impacts and possible management approaches. We expect to have Parks Dept. support on building additional exclosures, either for expanded monitoring or for preserving sensitive sites.
  3. FOSC will develop an outreach program that will:
    1. Post reliable information on deer management issues on our website, drawing from the wide range of experiences of jurisdictions throughout the region.
    2. Solicit insights from FOSC membership with expertise in biology, community organizing, homeowner associations, and other areas germane to the deer management issue.
    3. Begin covering the issue regularly in the FOSC monthly e-newsletter, including requests for germane information, e.g., experience with deer ticks, deer-vehicle collisions, damage to private gardens and landscaping, and damage to natural areas.
    4. Invite a Parks official to discuss the ecological state of the park at a program meeting (to include the impact of deer)
    5. Continue to discuss deer issues with officers of neighborhood associations, focusing on those upstream from Colesville Road.
  4. FOSC will establish one or more additional deer exclosures so that (a) certain valuable plants and/or habitats can be protected and (b) further data can be gathered on the impacts of deer and other animals.

Web Resources Cited in this Statement

Connecticut Department of Environmental Protection, Mananging Urban Deer in Connecticut: A Guide for Residents and Communities (2nd ed., 2007)

Maryland Department of Natural Resources, “Farmers and Hunters Feeding the Hungry,”

Montgomery County Deer Management Work Group, Comprehensive Management Plan for White-tailed Deer in Montgomery County, 1995 (revised 2007)

Montgomery County Deer Management Work Group, Montgomery County Deer Management Program, Deer Impact Data Collection and Results 1996-2007

Montgomery County Deer Management Work Group, Montgomery County Deer Management Program, Annual Report and Recommendations FY2009

New York State Department of Environmental Conservation, “Citizen Task Forces on Deer,”

Northeast Deer Technical Committee, An Evaluation of Deer Management Options, 2008