management of white-tailed deer: assessment and draft … · purpose of assessment and plan ......

Management of White-Tailed Deer: Assessment and Draft Plan

Purpose of Assessment and Plan • Review and summarize the ecological impacts of deer

on natural areas and habitat.

• Review information and research regarding deer populations and impacts on forest preserves (aerial surveys, vegetation studies) and public safety impacts (deer-vehicle collisions).

• Propose a mission and goals for the District’s deer management program.

• Evaluate deer management options.

• Recommend the most feasible options for the program.

Forest Preserve District Mission & Goals

Forest Preserve District Mission To acquire, hold and maintain lands within Kane County that contribute to the preservation of natural and historic resources, habitats, flora and fauna; and to restore, restock, protect and preserve such lands for the education, recreation and pleasure of all its citizens.

Our Goal To preserve and restore the nature of Kane County.

This is accomplished through the stewardship and conservation of the District’s natural resources using a program of restoration, research, management and public education.

Land Management and Restoration Staff and volunteers use a variety of techniques to recreate and restore habitat and to improve the diversity and resiliency of our natural areas.

• Seed collection, propagation and

sowing

• Controlled burning

• Invasive species control

• Tree planting/reforestation

Natural History & Biology of White-Tailed Deer White-tailed Deer (Odocoileus virginianus) • Males (bucks) usually weigh 150-250 pounds. • Females (does) usually weigh 100-150 pounds. • Mating occurs late October-January with a peak usually occurring in mid-November. • Females give birth to 1-3 young, most are born from late May through mid-June.

Diet • Deer are herbivores. • They feed mainly on herbaceous plants and the leaves, buds and twigs of trees and

shrubs (browse). Also consume grasses, acorns (and other mast), agricultural crops, garden and ornamental plants.

Deer Populations in Illinois • Nearly extirpated by habitat loss, and market and subsistence hunting by the late

1800’s. • Natural immigration occurred and restocking began in the 1930’s. • By the late 1950’s a hunting season was allowed in 33 counties. • Presently deer are abundant statewide and hunting is allowed in some form in every

county.

Factors in Overabundance

Humans Alterations to Landscape • Large predators of deer have been

displaced or eliminated.

• Urbanization and habitat loss have driven deer into smaller areas.

• Development, fragmentation, and succession of habitats have created an ideal mosaic of forested and open areas (edge habitat) in which deer thrive.

• Agricultural areas provide cover and large amounts of food for part of the year.

• In urban and suburban areas deer are becoming less exposed to hunting.

Factors in Overabundance

High Adult Survival • In a study within Cook and DuPage forest preserves, adult deer

survival was high (over 80% annually). • Deer-automobile collisions were the most common known cause of

death. • Absence of predators that consistently take adult deer.

Reproduction • The same study found reproductive rates for females were as follows:

16.5% of fawns pregnant (mean # of fetuses = 1.07), 96.8% of yearlings pregnant (mean # of fetuses = 1.61), and nearly 99% of adults pregnant (mean number of fetuses ≥1.90).

• In 5 years a single doe could potentially contribute 8 offspring to the population.

• Ideal habitat, good nutrition, mild winters, high survival and high reproductive rates are all factors contributing to high deer populations.

Ecological Impacts of White-Tailed Deer

Plant Conservation and Diversity • Deer are selective browsers and prefer

certain plants over others. • Repeated browsing can affect the ability of

plants to reproduce and persist (ex. Trilliums and Orchids).

• Sensitive species can decline or even disappear.

• In isolated woodlands, the ability of plants to naturally recolonize is limited.

Ecological Impacts of White-Tailed Deer Forest Regeneration • Overbrowsing can suppress the regeneration of desirable

native tree species (oaks and hickories) leading to a shift in woodland tree composition.

• Shade tolerant species (maples) and invasive species (buckthorn) become more prevalent.


Reforestation • Newly planted trees that are repeatedly browsed by deer have

reduced growth and lower survival rates.

• The District has planted 20,000 oak seedlings in the last 5 years as part of a long-term reforestation program.


Other Species • The loss of plant species, structural diversity and ground cover

in the forest understory affects birds and other species who require these areas for food, nesting and cover.

• The decline of native mast producing species in the canopy will affect many species including squirrels, chipmunks, mice, as well as deer. There will be less available food.

Impacts on Human Safety and Property Deer Vehicle Collisions • High deer populations in areas of high human population increase the potential

for deer-vehicle collisions (DVC). • Kane County averaged 510 DVC reported per year from 1994-2008.

Tick-borne Diseases • Lyme disease: deer are not the reservoir of the disease agent, but are the

preferred host of the adult stage of the primary vector, the black-legged tick. • Babesiosis: a parasite that affects blood cells in humans and can be severe. Deer

are not the reservoir for this disease, but are the preferred host of the adult stage of the tick that spreads the disease, the black-legged tick.

• Anaplasmosis: is a bacterial infection which affects white blood cells , it can transmitted to humans by the black-legged tick. Wide range of hosts including deer, rodents and livestock.

Property Damage • Deer browsing and antler rubbing can cause economic losses in agricultural

operations, orchards, and tree farms, as well as causing substantial damage to landscape and garden vegetation.

Deer Population Health: Chronic Wasting Disease (CWD)

CWD • CWD is a 100% fatal disease of the nervous

system that affects deer and elk.

• First found in Illinois in 2002, discovered in Kane County in 2010.

• Currently found in 4 Townships, 11 positive deer have been found in Kane County.

• The primary transmission route is most likely direct contact ( ex. nose to nose). Growing evidence suggests indirect transmission is important (environmental contamination).

• High deer populations are more conducive to the transmission and spread of CWD.

Research: Aerial Counts Helicopter Surveys • Beginning in 2008 aerial counts were conducted from a

helicopter.

• Conducted in winter when adequate snow cover exists (more than 3 inches).

• Two observers count deer while transects are flown across an area.

• Detection is imperfect, aerial surveys typically underestimate the number of deer.

Research: Aerial Counts

Aerial Counts • Considerable variation in deer densities overall.

• Several sites had consistently elevated densities.

0

10

20

30

40

50

60

Aurora West

Big Rock

Blackberry Maples

Bliss-Hannaford

Brunner Complex

Burlington

Burnidge

Dick Young

Freeman Com

plex

Helm W

oods

Johnson's Mound

LeRoy Oakes

Oakhurst

Deer

per

squa

re m

ile

2008-2009

2009-2010

2010-2011

Initial Goal

Research: Browse Studies

Browse Studies • Currently monitoring woody browse, indicator species, rare

plants and reforestation plantings at several sites.

• Outside research of Kane County woodlands has also occurred over a 20 year period.

− Found a decline in oak regeneration, decrease in shrub species richness, an increase in the dominance of maples, increases in invasive species.

− Changes were attributed to reduced fire and disturbances, canopy closure and overbrowsing by white-tailed deer.

• Woody browse surveys conducted thus far have recorded high levels of browse, shifting species composition, low presence of native shrub species, and low numbers of oak seedlings.

Browse Transect: Brunner Family FP

• Composition of native species in the understory (under 6 ft. tall). • Under current conditions oaks will gradually disappear and be

replaced with more common species, and invasive species.

Browse Transect: Freeman Kame FP (North)


replaced with more common species, and invasive species.

Browse Transect: Freeman Kame FP (South)


replaced with more common species, and invasive species. • No 2011 sample due to vandalism of transect markers.

Summary of Browse Data

Site Year Stems Counted

%browsed Median browse class (if browsed)

Class value*

Freeman North

2010 171 44.44 3 26% to 50%

Freeman North

2011 175 40.57 3 26% to 50%

Freeman North

2012 305 16.72 4 51%-75%

Freeman South 2010 977 55.68 4 51%-75%

Freeman South 2012 1276 61.83 5 76%-100%

Brunner 2010 141 13.5 2 1%-25%

Brunner 2011 55 36.36 3 26% to 50%

Brunner 2012 59 66.10 4 51%-75%

* Class value represents the percentage of stems browsed on each plant that showed evidence of deer browsing.

Research: Deer Vehicle Collision Data (DVC)

• Illinois Dept. of Transportation (IDOT) collects DVC data for all counties.

• The number of DVC per billion miles driven is used as a population index by the Illinois Department of Natural Resources (IDNR).

Results: Deer Vehicle Collision Data

0

50

100

150

200

250

DV

C p

er B

illio

n M

iles

Deer-Vehicle Collisions (DVC)

Kane

Cook

DuPage

• In Kane County, the highest accident rate was 237.2 DVC/billion miles in 1994 and the lowest accident rate was 135.9 DVC/billion miles.

Results: Deer Vehicle Collision Locations

Year % of all DVC within 500 feet of FPD property

2005 22%

2006 27%

2007 24%

2008 26.7%

2005-2008 24.9%

Need for Program

• Growing deer populations are a concern in Kane County and across the 8 county Chicago region.

• Population levels are increasingly at odds with maintaining plant diversity in natural areas, and at times impact the safety and property of the public.

• We have deer populations that are higher than most conservation agencies manage for, to maintain diverse and sustainable ecosystems.

• There is evidence of ecological impacts in some of Kane County’s finest natural areas.

Deer Management Program

Mission The mission of the program will be to maintain and enhance the diversity of flora and fauna within preserves. The program shall protect natural and restored plant communities from excessive deer impact by managing deer populations at levels compatible with the long-term health of ecosystems, using safe, effective and state-approved methods.

Deer Management Program

Program Goals and Objectives

Natural Resource Goal: Manage and maintain a healthy, stable deer population appropriate to the habitat present at District preserves.

• Population Objective: Establish population targets for deer at each site or complex of preserves.

• Ecological Impact Objectives: Establish site or complex-specific objectives related to habitat, plant communities and restoration efforts, to preserve and enhance native plant communities and their associated fauna.

Public Safety Goal: Enhance the safety of the public through management where possible.

• Public Health and Safety Objectives: Establish site or complex-specific objectives related to the enhancement of the health and safety of the public. Reduce DVC in management areas. Research zoonotic diseases.

Communication Goal: Maintain communication with preserve users and preserve neighbors.

• Communication Objective: Maintain communication with the public regarding deer management activities, current research and information for resolving deer issues.

Evaluation of District Sites

• Priority given to highest quality natural areas. − Dedicated Illinois State Nature Preserves, Illinois Natural

Area Inventory Sites. − Presence of threatened, endangered species, and species

of concern. − Sites with high floristic quality and rare habitat types.

• Other factors − Future large scale restoration projects (i.e., reforestation

plantings).

• Sites with elevated deer densities based on aerial surveys − Densities above 15-20 deer/mi2 will result in vegetation

monitoring to assess impacts.

• Documented excessive damage to vegetation and elevated deer densities will result in designating a site for management consideration.

Deer Management Options: Non-Lethal

Take No Action • Implications in the long term on vegetation structure and

diversity, sensitive and rare species, habitat quality, wildlife, and human health and safety.

• Must accept that high quality ecosystems will be degraded by intense deer browsing and attempt to restore other areas with the influences of high deer densities.

• Not compatible with the District’s mission or duty to be responsible stewards of public lands if deer populations are in conflict with conservation and management goals.


Apply Repellents • Require multiple applications yearly.

• Application is time and labor intensive.

• Cost approximately $100 per gallon and can treat roughly 400 tree saplings.

• Repellents appear to decline in efficacy when deer populations are high, as feeding pressure can overcome the repellents effects.


Install Fencing • Restricts movements of many species, not just deer.

• Would restrict the movements of preserve users.

• Costly, 2200 linear feet of 8 foot fence was recently quoted at $55,000.

• Fencing or caging can be used to protect small, rare populations, not practical on large scales (cost, roads, streams, utility right of way).

• Extensive fencing would degrade the aesthetic qualities of natural areas.


Trap and Relocate • Mortality rates of 66% to 85% have been documented within

1 year post relocation.

• In 1990-1991 Lake County FPD reported costs of $603 to $1,261 per deer.

• Potential to spread diseases like CWD.

• IDNR will not issue deer population control permits for this method.


Fertility Control • Methods: surgical sterilization, hormone implantation,

immunocontraception.

• Surgical sterilization requires the capture of each female, a veterinarian and surgery, costs are reported at $1075 per deer in a recent Cornell project.

• Treating males is not effective because deer are polygamous in mating (one male can mate with many females).

• Immunocontraception requires the darting or capture of each female.

• Immunocontaceptives currently require multiple treatments over time.

• 70-90% of females need to be treated to cause a decline in population growth over time.

• The cost of labor, materials and the feasibility of treating an adequate number of deer will likely limit the use of immunocontraceptives to small insular herds that are habituated to humans.

• IDNR will not issue deer population control permits for experimental techniques.


Supplemental Feeding

• Could encourage increased reproduction, which would increase ecological impacts.

• Can result in increased browse pressure and damage near the feeding sites.

• State law prohibits the feeding of deer.

Deer Management Options: Lethal

Predator Reintroduction • Coyotes are the primary predator of deer in northern Illinois,

but generally take fawns.

• Current predation sources are unlikely to substantially reduce deer populations.

• Reintroducing large predators (wolves or mountain lions) that would commonly take adult deer is impractical for ecological (lack of large habitat areas), social (safety concerns), and legal reasons.


Controlled Archery Hunting • Use hunting during the established season (Oct 1- Jan 20)

as a management tool.

• Controlled hunts allow additional rules and restrictions to address safety concerns and other issues unique to each site.

• Program costs can be covered by participant fees, rather than tax revenue.


Sharpshooting • Must be conducted under a Deer Population Control Permit

from IDNR.

• Sharpshooting entails the culling of deer at pre-selected locations when preserves are closed to the public.

• Deer must be processed and the venison must be donated to charity/food pantries.

• Processing costs range from $30-$60 per deer.

• Existing staff can be qualified as marksmen and markswomen to limit additional personnel costs incurred.

Deer Management: Other Agencies

Conservation Agency

Deer Management

Sharpshooting

Hunting

Forest Preserve District of Cook County Yes Yes No

Forest Preserve District of DuPage County Yes Yes No

Forest Preserve District of Lake County Yes Yes No

Forest Preserve District of Will County Yes Yes No

McHenry County Conservation District Yes Yes Yes

Boone County Conservation District Yes No Yes

Forest Preserve District of Winnebago County Yes Yes No

Forest Preserve District of Rock Island County Yes No Yes

Forest Preserve District of Kendall County No No No

Proposed Methods

• The District is already using non-lethal means (i.e. repellents and limited fencing) to mitigate deer impacts where practical and applicable.

• It is impossible to implement these methods over large areas, such as at 1,000+ acre preserves.

• Currently, a field-proven, state approved non-lethal means to reduce overabundant free-ranging deer populations does not exist.

Proposed Methods

The two primary lethal means of removal recommended are:

1) Controlled hunting within the established deer hunting seasons.

2) Sharpshooting under a DPCP permit from IDNR.

• These are the methods most commonly used by Forest Preserve Districts and Conservation Districts in Northern Illinois.

• These methods are not mutually exclusive, and depending on the location and other factors, controlled hunting can be utilized initially or during the “maintenance phase” of deer management after sharpshooting in the “reduction phase”.

Proposed Methods: Controlled Archery Hunting • Safety would be the top priority of the program. • If approved, controlled hunts would be conducted within the season

established by IDNR. • Program participants must comply with IDNR rules and regulations

as well as District rules and regulations. • Proof of completion of an approved hunter safety course would be

required. • Participants would be required to attend an Orientation Meeting

and qualify during an archery proficiency test. • Program participants would be chosen by a lottery open to Kane

County residents only. • The District would establish management zones based on safety

concerns, available habitat, preserve boundaries, trails, access points, and recreational, residential and other developed areas.

• A fee structure will be established to help offset the cost of managing the program.

• The collection of a sample for CWD testing would be mandatory for participation.

Proposed Methods: Sharpshooting

• Safety would be the top priority of the program.

• If approved, sharpshooting would take place in areas that cannot accommodate controlled hunts or where controlled hunts alone are not sufficiently reducing the deer population.

• The District would comply with all regulations and requirements of the IDNR’s Deer Population Control Permit (DPCP).

• Marksmen and markswomen would be required to successfully complete the IDNR qualification process.

• Sharpshooting activity would be implemented while preserves are closed, which allows normal preserve use and ensures public safety.

• The venison from all deer taken under a DPCP would donated to charitable organizations as is required.

Preliminary Site Identification

• Priority for management (elevated densities, documented ecological impacts).

• Freeman Kame Complex (contains Illinois State Nature Preserve)

• Brunner-Fox River Shores Complex

• Priority for monitoring for future management (elevated densities, presence of high quality natural areas, large restoration efforts).

• Helm Woods(contains Illinois State Nature Preserve) • Burnidge • Big Rock • Aurora West

Summary • Similar to other urban and suburban areas in the Chicago Area

and throughout the United States there is evidence of elevated deer populations at many District properties.

• Some populations are well above levels where other conservation agencies have observed substantial impacts to natural areas.

• There is evidence of ecological impacts in some of Kane County’s finest natural areas.

• Responsible stewardship and natural resource management require that we manage our natural areas for the long-term benefit of all species.

• Having evaluated the options currently available for managing deer populations, controlled archery hunts and sharpshooting are the only safe, effective and State-approved methods for reducing free-ranging deer populations.

• Deer management is not a one time event, it is a long-term commitment.

management of white-tailed deer: assessment and draft … · purpose of assessment and plan ......

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