The Hudson Valley is a treasured landscape that has undergone tremendous change over the past century. This forum explores how science-based stewardship on private land can help protect and promote healthy forests and open spaces, now and for future generations. Presentations explore threats our forests and natural areas face – from invasive species and climate change to deer overabundance – and actions that can be taken on a site-by-site basis to optimize conditions. A special focus will be given to the overlap between sport hunting and conservation communities, with a roundtable discussion on advancing common ground. Hosted April 12, 2014 at Cary Institute of Ecosystem Studies Presentation Part IV by: Raymond Winchcombe, Wildlife Ecologist, Cary Institute of Ecosystem Studies

1. Impacts to Forests by Deer and the Use of Annual
Controlled Hunts to Mitigate those Impacts
www.pa.audubon.org/search/node/PA Deer
Ecosystem Forum Report

2. Take Home Message
• Deer overabundance leads to serious negative impacts
on forested ecosystems.
• These impacts affect the abundance, distribution and
diversity of plant & animal species.
• Over-browsing by deer threatens the survival &
perpetuation of our oak dominated forests.
• Loss of oaks & the mast they produce would be
devastating for a host of animal species & an economic
loss of timber resources.
• A hunting program focused on consistent female
removal can address the impacts of over-browsing by
deer.

3. Valley Forge, PA - 2006

4. Robust Forest Under story

5. Discussion Outline
• Life History of White-tailed Deer
•Impacts to Forest Ecosystems by Deer
•Cary Institute’s Deer Management Program
•Role of Hunters & Landowners in Managing Deer

6. Deer Facts You Should Know

7. • Most abundant large herbivore in the United States
• Can live a long time; 10+ years in the wild
• Exhibit a polygamous breeding system
• Potential for rapid population growth in the absence
of predators
• Humans are the most significant contemporary
predator in most areas

8. • Adult females usually have twins, triplets possible
• Yearlings usually have singles, twins possible
• Well nourished fawns can breed & produce a fawn
their first year
• Single male will breed with several females
Reproduction

9. Population growth experiment results:*
1928-34 6 deer grew to 222 in seven years
1975-80 10 deer grew to 212 in six years
* - George Reserve in southern Michigan inside a 1,146 acre fenced site
controlling for all sources of mortality.

10. Polygamous breeding system requires control efforts
be focused on females if population control is desired.
Contrary to early deer management efforts where
females were protected & herds allowed to expand.
Early Goals: restock ranges where deer were
extirpated due to market & subsistence hunting &
habitat destruction.

11. Deer Impacts to Forested Ecosystems

12. Ecological Impacts of Too Many Deer
• Over browsed habitats
• Reduced species diversity (Flora)
• Reduced species diversity (Fauna)
• Loss of forest structural diversity
• Loss of forested systems functionality
• Overall decline in deer health/disease transmission

15. Valley Forge, PA - 2006Valley Forge, PA - 2006

16. Deer are Selective Browsers
• Select foods that are
nutritious and highly
palatable
• Selections based on food
availability (feeding
progresses from most
desirable to least desirable
species)
• Food abundance & species
diversity are dependent on
contemporary deer #’s &
historical deer densities
0
500
1000
1500
2000
2500
3000
3500
#Budsavailable
Mean Available Buds/Species - 1998-2013
0
2
4
6
8
10
12
14
16
%BudsBrowsed
Mean % Browsing on Index Species
Cary Institute - 1998-2013

17. Overbrowsing: Direct Effects
• Reduced species richness & abundance
• Altered species composition (loss of desired species)
• Reduced advanced regeneration of desirable species
(important timber & mast producing species)

18. Hunting focused on
recreation
Regeneration progressing nicely Regeneration stalled
Hunting focused on habitat
protection
Not all hunting is equally effective

19. Overbrowsing: Indirect Effects
• Proliferation of undesirable & browse resistant
species (Hay scented & NY fern, beech, striped maple)
• Can lead to a shift in balance between native &
introduced species (introduced species less palatable)
• Can change the direction of forest development
(competitive exclusion of desirable by undesirable species)
• Reduced abundance of forest dwelling animals (direct
competition for food [acorns], altered habitats)

20. Gun Club Fern Understory

21. Impacts of Structural Component Loss
Loss of shrub & mid-canopy layers & spatial
distribution of these layers:
• Songbirds: reduced species richness & abundance (loss of
feeding, nesting & escape cover).
• Reduced abundance & higher predation on small mammal
community; eventual decline in predators.
• Insect diversity is dependent on vegetation diversity
(feeding, egg deposition, larval development).

22. Valley Forge, PA - 2006Valley Forge, PA - 2006

23. Structural/Habitat Loss
• Microclimate shift: increased
light, wind, temperature and lower humidity at the
forest floor (impacts germination & survival of some tree
species, snails, salamanders, frogs etc.)
• Higher survival of less desirable shade intolerant
species due to increased ambient light conditions
(Hay Scented Fern).
• Degraded or loss of habitat for deer (loss of wintering
areas, escape cover, food resources).

24. Deer Population Management at the
Cary Institute of Ecosystem Studies

25. Deer Population Management Options
1. Allow nature to take its course
2. Trap & transfer excess deer
3. Use fertility control agents to regulate herd size
4. Reintroduce predators to control deer numbers
5. Control deer numbers with sharpshooters
6. Use regulated hunting

26. Program Goals
Protect the structure & function of
forested ecosystems.
Minimize conflicts with planned uses of
the property.
Cary Deer Management Program

27. Program Elements
• Vegetation monitoring - via surveys
• Population index - hunter observations
• Population control - annual hunts
Cary Deer Management Program

28. Vegetation Monitoring
• 45 Deer browse survey areas (spring)
• 4 deer exclosures with paired unfenced plots
Cary Deer Management Program

29. 0
2
4
6
8
10
12
14
16
18
97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 AVG
%Browsed
Year
Percent Buds Browsed for All Species
Cary Institute 1997 - 2013
Mean
Cary Browse Survey Results – 1997 - 2013

30. 0
2
4
6
8
10
12
14
16
%BudsBrowsed
Mean % Browsing on Index Species
Cary Institute - 1998-2013
Cary Browse Survey Results 1998 - 2013

31. IES Site 1
0
10
20
30
40
50
60
70
80
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
IES Site 2
0
20
40
60
80
100
120
140
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
IES Site 3
0
5
10
15
20
25
30
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
IES Site 4
0
20
40
60
80
100
120
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
Cary Institute’s Deer Exclosure Sites

32. Gun Club Site 1
0
20
40
60
80
100
120
140
160
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
Gun Club Site 2
0
10
20
30
40
50
60
70
80
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
Gun Club Site 3
0
10
20
30
40
50
60
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
Gun Club Site 4
0
20
40
60
80
100
120
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
Gun Club Location

33. Hunter Observation Method

34. Bowhunter Data Collection Bucks
Does
Fawns
Unknowns
Days Hunted
Hrs. Hunted
Area Hunted

35. Summary Deer Observation Data

36. Population Control

37. Population Control - Annual Reductions
Specific Goals
• Stabilize or reduce local deer numbers
• Achieve younger female age distribution
• Efficient and safe control effort
Cary Deer Management Program

38. Population Control via Controlled Access Hunt
• Participation by invitation
• Firearms proficiency requirement
• Orientation meeting requirement
• Antlerless permit requirement
• Effort requirement
Cary Deer Management Program

39. Shooting Proficiency Test
3 shots on a 12” X 12” target
Maximum of 5 shots allowed

40. Cary Deer Management Program
Population Control - Hunt Specifics
Daily sign in/out at check station
Required deer check
Blaze orange requirement
Designated parking areas
Avoid research & restricted areas

41. Cary Institute Hunter Check Station

45. 0
5
10
15
20
25
30
35
40
45
50
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
#ofhunters&trips
Hunt Sectors
Avg. # Different Hunters and Avg. # of Trips by Sector - 2005-12
Mean # different hunters Mean # trips

46. 0
5
10
15
20
25
30
35
40
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
Total#Deer
Hunt Sector #
Deer Harvest by Hunt Sector 2005-13
2005 2006 2007 2008 2009 2010 2011 2012 2013

47. Cary Deer Management Program
Population Control - Hunt Specifics
Daily sign in/out at check station
Required deer check
Blaze orange requirement
Designated parking areas
Avoid research & restricted areas

48. Cary Institute Deer Check Facility

50. Tick Collections from Harvested Deer

51. Hunter Evaluation
• Compliance with rules and policies
• Hunter effort
• Hunter success (adult females)
• Cooperation and attitude
Cary Deer Management Program

52. Population Control – Summary
Averages – 1976-2013 (#)= range
• 53 hunters (30-89)
• 2,124 hrs. of effort (1128-2799)
• 55 deer removed per year (22-89)
• Hunter success rate - 66% (range 38 – 82%)
Cary Deer Management Program

53. Males
51%
Females
49%
Proportion of Deer in the 1976-2013
Deer Harvests at the Cary Institute

54. Landowner’s Role in Deer Population
Management

55. Landowner’s Role in Deer Management
1. Control access to the resource
2. Should take a pro-active stance in deer mgmt.
3. Can customize programs/access as needed
4. Require doe harvest for access privileges
5. Require sincere hunter effort for access privileges
6. Don’t tolerate irresponsible behavior

56. The Role of Hunters in Deer Population
Management

57. Role of Hunters in Deer Management
The primary role of hunters in deer population
management is the removal of deer.
Hunters are the tool deer managers use to control
deer numbers.
To maximize their effectiveness, hunters must
focus their efforts on adult females.
Hunters provide important ecosystem level
services to the community when adequate female
harvests are achieved.

58. Hunter Responsibilities
1. Safety, safety, safety
2. Respect- for property & all persons
3. Exhibit the highest of ethical standards
4. Zero tolerance for unsafe & unethical behavior
5. Never forget, access is a privilege
6. Embrace their role as deer managers when making
decisions regarding which deer to harvest.

59. Challenges for Deer Managers

60. Challenges for Deer Managers
1. Adequate access at the landscape scale?
2. Sufficient numbers of antlerless permits?
3. Sufficient hunter effort ( #’s of hunters)
4. Focused hunter harvest (adult females)
5. Providing a quality hunting experience ?

61. Is There a Recreational Threshold?
Is there a deer density at which many hunters do not see
enough deer to justify continuing to hunt? (Moyer and
Shissler).
Basis for a Recreational Threshold – expectations based on
past experience
Problem: Oscillations in deer #’s based on hunter interest
would not be good when the management objective is
forest ecosystem /habitat protection .
Challenges for Deer Managers

62. Result When the Need to See more Deer Trumps Habitat Protection

63. Questions ?

64. Primary Question
Are these oak dominated forests positioned to perpetuate
themselves under these different deer management scenarios?

65. 1976 – 2013 Summary Stats, Firearms
284 Different Hunters Participated
15,746 Hunter Visits
67,030 Hours of Hunting Effort
2,078 Deer Harvested (171 additional deer with archery)
2,249 Total Hunter Harvest (mean 58/yr.)

67. Linking hunters and landowners
P.G.C. must attempt to match the general population, who are
the owners of public and private land, with those who hunt in a
way that is beneficial to both and mutually agreeable. This is
likely to depend on the willingness of P.G.C. to:
• enforce trespass laws on private land
• surrender the traditional value of equitable distribution (the
concept that all hunters should harvest an equal number of
animals)
• adopt more liberal season and bag limits that would allow
hunters to be effective in resolving landowners’ problems with
deer overbrowsing
Cited from the PA Audubon Deer Ecosystem Forum Report

68. IES Deer Exclosure Study
Ray Winchcombe & Charles Canham
• Central Dutchess County
• 3 Locations
• 4 sites/location
• 2 plots/site (fenced & unfenced 10x10 M plots)
• 1992 - present

69. Deer Management Scenario's
• Unhunted property – 1,000 acres; primarily forested
habitat (borders 900 acres of hunted forest lands).
• Gun club property – 1,500 acres; mix of
forest, cultivated field & old field habitat. Several
decades of deer hunting; inconsistent doe harvest
policy. Focus is on recreation and hunter satisfaction
• Cary Institute – 2,000 acres; mix of forest, old field &
open field habitats. Over three decades of deer
population management via controlled access
hunting; consistent doe harvests. Focus is on
protecting the structure & function of the forested
ecosystem.

70. High tensile, woven wire mesh fence 6.5’ tall (10x10 m)

71. Unhunted Site 1
0
5
10
15
20
25
30
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
Unhunted Site 2
0
20
40
60
80
100
120
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
Unhunted Site 3
0
20
40
60
80
100
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
Unhunted Site 4
0
5
10
15
20
25
30
35
50-99 100-149 150-199 200+
Height Class (cm)
#ofSaplings
Fenced Unfenced
Unhunted Location

72. Response to Primary Question
Unhunted site: data suggests this oak forest will not be able to perpetuate itself.
Complete lack of any advanced regeneration.

73. Response to Primary Question
Cary Inst.: data suggests this oak forest will perpetuate itself. Presence
of seedlings in the various height classes bodes well for this forest.
Focused deer management must continue.

77. Consequences of Deer Over Abundance
• Severe overbrowsing of forested habitats
•Altered plant species composition, distribution &
abundance
• Reduction of understory structural diversity
• Reduced habitat quality (deer & other fauna)

78. When overly abundant, deer can have serious
negative effects on forest communities
• Mechanism – consumption of vegetation
• These effects can be either direct (species loss) or
indirect (shifts in species composition).
• Overbrowsing alters the physical structure of forests
thus having a negative impact on a host of other animal
species (vertebrate & invertebrate).
• High deer densities & overbrowsing combine to
threaten the future existence of our forests as we know
them today.

79. Consequences of Deer Overabundance
• Long-term reduction in BCC (deteriorated winter habitat)
• Decline in herd health (disease transmission, losses)
• Conflicts with CCC (acceptable limits that people will endure)
• Increased frequency of deer/vehicle encounters
• Excessive damage to agricultural, nursery &
landscape plantings & timber production.

80. IES Archery Hunting Areas Map

87. Day of the Month - Nov./Dec.
18 19 20 21 22 23 24 25 26 27 28 29 30 1 2 3 4 5 6 7 8 9 10
Day of Season
M T W TH F Sa Su M T W Th F Sa Su M T W Th F Sa Su M T
Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 T. Hrs. T. Days # 5+ Hrs. Succ. Deer Harv.**
Acuti 8 7 7 7 2.5 6 37.5 6 5 Y D
Alexander 9 7 6.5 5 2 8 3.5 5.5 3 4 3 2 3.5 3.5 3 5 2.5 3.5 5 2 2.5 89 21 8 Y B
Beasley 1.5 1.5 6 1.5 6 7 2 3.5 1.7 2.5 3.5 4.5 2.5 4 47.7 14 3 Y B*,D*,D
Beck 3 5 5.5 3 4 3 23.5 6 2 N
Cahill 6 6 5 6 23 4 4 Y B
Clarke S. 5.5 3.5 3.5 4.5 4 3 3 27 7 1 N
Clarke B. 9 5.5 3.5 3.5 4.5 4 3 33 7 2 Y B
Corona 9 7.5 7 7.5 2.5 8 2 5.5 49 8 6 Y B,F
Crandall 5 8 6.5 7.5 27 4 4 Y D
Crooker J. 9 4 8.5 4 8.5 8.5 6.5 8.5 8 3 5 73.5 11 8 Y B
Crooker Jy. 9 4 8.5 4 9.5 8.5 8 8.5 8 68 9 7 Y D,F
DeBonis 3.5 3.5 2.5 9.5 3 0 N
Diggelmann 3.5 3.5 7 2 0 N
Dodaro S. 5 4.5 5.5 6 2.5 6 2.5 2 4 5 2.5 5 1.5 52 13 6 Y B,D,D
Record of Hunter Effort & Success