Deer Pellet Project

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Deer Pellet Survey

Eldora Nature Preserve

A Comparison of Two Years

By: Theresa Quelch


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Abstract

When looking into allowing hunting on the Eldora Nature Preserve, the NatureConservancy needed to find some way to measure the effectiveness of such a hunt on the

white tailed deer population. While searching for an answer to that question, The Nature

Conservancy came across a study that could calculate the deer density by looking at deer

pellets. This method called the Fecal Pellet Index (FPI) has been used many times in various

wildlife preserves and nature parks around the world and seems to be adequate in its

population estimation. The Nature Conservancy decided to try to follow the study and first

obtained a baseline of deer populations during 2010. Once this was done they opened the

preserve to hunting by a few select individuals and kept a log of the number of deer taken. Two

years later in 2012, the deer pellet survey was done again and the results of the two studieswere compared. This was done to see if there was any evidence that the hunt was successful

on controlling deer populations, which would hopefully prove to be just as successful for

controlling habitat destruction by the white tailed deer.

Introduction

When you think of a wildlife preserve or nature park in the north eastern parts of the

United States, you most likely imagine that there will be white tailed deer hidden somewhere

among the trees and shrubs. Indeed the white tailed deer is one of the most numerous animals

in the north east (Miller, 1989), possibly only second to the grey squirrel. White tailed deer

have come to be one of the most easily recognized animals by people no matter if they live in a

city or in the country. That being said, these animals have managed to both pull at peoples

heart strings as well as to induce a sense of sportsmanship, the combination of which could

start a debate in almost any social circle (Sue Canale, Wildlife Biologist, Lecture Notes from

Wildlife Management 2011).

In truth, the white tailed deer is indeed a valuable animal in the habitats where it calls

home. In fact it has even been considered a keystone species because of its invaluable impact

on all the other species it the same habitat (Sue Canale). Without the presence of the white

tailed deer most carnivores that inhabit those habitats would starve to death and become


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extinct. Likewise, the white tailed deer easily controls the growth of forest plants by browsing

on them to obtain nutrition (Sue Canale).

Unfortunately, as with any habitat in which people have invaded, there has been a

breakdown of the natural system of the habitat in which the white tailed deer calls home. With

the introduction of people and the building of neighborhoods, there is an increase in palatable

and nutritious vegetation and a decrease of predators (Sue Canale). This situation has allowed

the population of white tailed deer to explode and grow exponentially (Sue Canale). This

imbalance, along with limited wild lands, has turned the white tailed deer into a detriment to

those remaining wild tracks of land. This is because the white tailed deer has a habit of

destroying preserved land by over browsing when their populations become too large in

number (Sue Canale). When this happenswildlife managers must find some way to control

those ever increasing numbers, before they completely destroy their own natural habitats and

in the end themselves. This has not been an easy task for wildlife managers, because of the

general disagreement on the best methods to reduce population numbers. Presently hunting

remains the best practice available for population control (Sue Canale); however it is not always

well received by the public. Taking public concerns into consideration, it is still up to the wildlife

managers to find the best method of white tailed deer population control. To do this wildlife

managers need to be able to compare the results of various population control methods.

When looking at managing the population of deer in a given area, it is good to be able to

determine if what you are doing is working or not. The best way to do this is to take a total

count of the population before and then after management. However when speaking of

populations of white tailed deer, it is difficult to imagine being able to capture and count everysingle deer in the specified population. Therefore the best thing to do is to find a way to

sample the population and come up with a model to calculate the amount of deer that are in

the specified area (Zar, 2009). After that has been done, wildlife managers can take a sample

before and then after management and compare the results to see if the management actions

have worked.

The Nature Conservancy, which is an environmental group that seeks to protect wildlife

and preserve natural habitats, has noticed that their local preserves are suffering from white

tailed deer over population. Knowing that this issue could cause major problems and

destruction of the habitat, they had decided to allow hunting on their preserves to help control

the population. Hunters interested in the preserve hunting were required to attend a course

and follow specific instructions (See Appendix). The scientists of the Nature Conservancy also

decided to monitor the effects of the hunt by following the Fecal Pellet Index study of David

Forsyth.


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Methods

For this deer pellet survey we followed David Forsyths study: Protocol for estimating

changes in the relative abundance of deer in New Zealand forests using the Fecal Pellet Index

(Forsyth,2005), with minor variation. Some of the things we did differently were to cut the

total transect to 100 m instead of 150 m. This change was made because of the limited range

of the study area at the Eldora Nature Preserve.

In 2010, thirty transect starting points were randomly assigned along the three trails of

the Eldora Nature Preserve. These starting points were marked both with a piece of pink tape

that had clearly written transect numbers on it and with the use of a GPS system. In that same

year the transect starting points were used to follow a 100 m transect line north of the starting

point. Sample areas were taken at intervals of 5 m along the transect line, using a system of

two stakes tied to a 5 m line which was marked on both sides exactly 1 m from the stake. The

area that the deer pellets were searched for was only in a 1 m radius around the point at which

the stake was located. The number of piles and the number of pellets per pile were counted

and recorded for each 1 m area located every 5 m along a 100 m northern transect line from

the path, at the randomly selected starting points. If an obstacle of significant size was

reached, then the protocol said to turn the transect 90 degrees, so that if you were heading

north you would be heading east when an obstacle was reached. Once that had been done the

data was briefly analyzed using Excel to calculate the Fecal Pellet Index (FPI) (Forsyth, 2005).

The process was repeated at the same transect starting points in 2012. Once both

studies were done the results were analyzed and compared using Excel and an Excel add on

called bootstrapping. This method followed the method in David Forsyths study (Forsyth,

2005). Comparing the results using statistical analysis of the means, it was easy to see that

there was a difference in deer density between the two years. From this information we will be

able to draw conclusions on whether the hunt was successful in reducing the deer population.

This study will also allow the Nature conservancy to decide if they need another hunt, or if thepopulation is sufficiently below the carrying capacity for the Eldora Preserve.


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Map


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Results

Transect results for 2010 study:

Transect Pellet Total Transect Pellet Total

1 31 16 0

2 0 17 0

3 0 18 2

4 11 19 196

5 0 20 9

6 0 21 298

7 No data 22 No data

8 No data 23 43

9 63 24 0

10 106 25 011 0 26 0

12 0 27 0

13 3 28 57

14 0 29 0

15 34 30 0

Bootstrapping ResultsMean Variance Lower Confidence Limit Upper Confidence Limit

31.61 168.48 3.48 79.63

From the data above, it is easy to see that the mean FPI for the 2010 study was 31.6

with a 95% confidence interval of 9.9-60.3. This means that there is a greater than 5% chance

due to random sampling error alone that the FPI for 2010 is true. Therefore I have failed to

reject that 31.6 is the FPI for 2010.


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Transect results for 2012 study:

Transect Pellet Total Transect Pellet Total

1 0 16 02 0 17 0

3 105 18 0

4 0 19 0

5 0 20 0

6 0 21 4

7 0 22 0

8 0 23 0

9 0 24 0

10 50 25 0

11 0 26 40

12 63 27 0

13 76 28 0

14 0 29 40

15 2 30 87

Bootstrapping ResultsMean Variance Lower Confidence Limit Upper Confidence Limit

15.50 30.17 5.73 26.87

From the above data, it is easy to see that the mean FPI for the 2012 study was 15.5

with a 95% confidence interval of 5.7-26.9. This means that there is a greater than 5% chance

due to random sampling error alone that the FPI for 2012 is true. Therefore I have failed to

reject that 15.5 is the FPI for 2012.


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Comparison Results for 2010 and 2012:

From the above table, it can be seen that there was a big difference on the location of the deer

pellets from one year to the next.

Transect Density Change Transect Density Change

1 -3.47 16 0

2 0 17 0

3 4.66 18 -1.10

4 -2.48 19 -5.28

5 0 20 -2.30

6 0 21 -4.09

7 N/A 22 N/A

8 N/A 23 -3.78

9 -4.16 24 010 -0.74 25 0

11 0 26 3.71

12 4.16 27 0

13 2.96 28 -4.06

14 0 29 3.71

15 -2.46 30 4.46

0

50

100

150

200

250

300

350

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 27 28 29 30

Totalpellets

counted

Transect points

Comparison of results for two years

2010

2012


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Comparison Bootstrapping ResultsMean Variance Lower Confidence

Limit

Upper Confidence

Limit

r -0.34 0.24 -1.28 0.64

Lambda= er 0.71 1.27 0.28 1.90

% change

=(er-1)*100 -28.73 27.13 -72.28 89.55

The negative sign tells us that there was a decrease in the FPI while a positive number

tells there was an increase in the FPI.

From the data above, we can see that there is a mean FPI difference from the 2010

study to the 2012 study is -0.34. The confidence interval is -1.28 to 0.64. This means that there

is a greater than 5% chance due to random sampling error alone that the mean difference in FPI

for the two years is true. Therefore, I fail to reject that -0.34 is the FPI difference between the

two years.

Discussion

Looking over the results we can see that there is indeed a change in the overall total of

deer pellets found as well as where the pellets were found. The difficulty is in that there was

very little statistically significant difference in the rates and percentages of change. The fact

that the confidence interval was so large and contained both results for an increase and a

decrease in the FPI made analysis difficult. .

There is a good possibility that the data itself could have had some minor problems. One

such problem was that according to Forsyth, it would be ideal to have the same observers for

all years of study (Forsyth, 2005). He goes on to explain that there are variations among

observers and that could be a confounding factor that could be easily eliminated. Forsyth also

suggests that anyone doing the survey should undergo some sort of training to help minimizesome of that variation among observers. Other studies debate the correlation of the FPI to the

total number of deer in the population (Fuller, 1991)

Another possible confounding factor to the study could be time of year and weather

variation. It has been well noted that 2012 has been an interesting year with a warm winter

and little to no rain. What if any effects this could have on white tailed deer activity is unknown;


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however it could play a part in the variation we have seen in pellet locations. A warmer winter

could also have affected the normal eating habits of the white tailed deer in the area. No snow

and cold has allowed for fields to have some vegetation, and this could be cutting back the

number of deer and the frequency of the deer to be in the more forested areas, such as the

Eldora Nature Preserve.

Finally, possibly the most important area for confounding factors is the ruminate

digestion system in and of itself. There was some research that states that it can take up to 15-

20 hours for the initial digestion of the first stomach of a ruminate ( Ingalls, Tesar, carpenter,

1994). It could be that the sample area is where the deer spend more of their digestion time

and little of the defecation happens there. More research into white tailed deer digestion and

behavior is needed.

This being said I would conclude that more studies are needed in the future to better

monitor the situation. Doing more studies will help to better understand the effects of huntingon the white tailed deer population.

References

Forsyth, David.2005. Protocol for estimating changes in the relative abundance of deer in New

Zealand forests using the Fecal Pellet Index (FPI). Department of Conservation

Fuller, Todd.1991.Do pellet counts index white tailed deer numbers and population change?

Journal of Wildlife Management 55(3):393-396

Ingalls JR, Thomas JW, Tesar MG, Carpenter DL. 1994 Relations between ad libitum intake of

several forage species and gut fill. Journal of Animal Science. 25(2):283-289

Miller, F.L. 1989.White Tailed Deer. Retrieved 4/12/2012 from Hinterland Whos who.

http://www.all-creatures.org/hope/DOE/3%20-%20Hinterland%20Who's%20Who%20-%20White-

tailed%20Deer.htm

Zar,Jarrold.2009. Biostatistical Analysis. Peasron Publishing, in Illinois
http://www.all-creatures.org/hope/DOE/3%20-%20Hinterland%20Who's%20Who%20-%20White-tailed%20Deer.htmhttp://www.all-creatures.org/hope/DOE/3%20-%20Hinterland%20Who's%20Who%20-%20White-tailed%20Deer.htmhttp://www.all-creatures.org/hope/DOE/3%20-%20Hinterland%20Who's%20Who%20-%20White-tailed%20Deer.htmhttp://www.all-creatures.org/hope/DOE/3%20-%20Hinterland%20Who's%20Who%20-%20White-tailed%20Deer.htmhttp://www.all-creatures.org/hope/DOE/3%20-%20Hinterland%20Who's%20Who%20-%20White-tailed%20Deer.htm


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Appendix

Deer Hunting Report for The Nature Conservancys New Jersey Delaware

Bayshores Program, hunting season 2011-2012

This data represents the totals for our 2011-2012 Deer hunting program. There were six

preserves, Eldora, Indian Trail Swamp, Lizard Tail Swamp, Lummis Ponds, Gandys Beach and

Willow Grove Lake. The program consisted of open hunts where there was no limit of hunters

and permitted hunts where only one hunter per 20 acres was allowed. Gandys beach data

was lost due to someone stealing the sign in box and all data sheets.

Summary of DBP hunting program:

The Nature Conservancy Delaware Bayshores Program allows hunting on select preserves in order to

maintain or restore the integrity of sensitive species and biological communities. At many of our sites,

deer populations have grown beyond the ability of the natural communities to support them. By

controlling deer populations, a carefully managed hunting program serves as a tool to reduce the damage

that deer can cause, allowing natural communities to support a broader range of diversity.

General hunting program guidelines

Interested hunters had to attend a hunter orientation to be eligible to hunt on TNC lands.

Open, No Limit = All interested hunters attending an orientation meeting were issued a permit

Limited Hunt = A limited number of permits were issued (based roughly on size of preserve/parcel).o Selected hunters were notified and issued a permit prior to the start of the hunting season.

TNC Preserve Location Type of Hunt Zone Permit Type

Eldora Nature Preserve Cape May

County

Bow, Firearm 34 Open, No

Limit

Gandy's Beach Preserve

New for 2011!

Cumberland

County

Bow, Firearm 30 Limit by Acre

Indian Trail Swamp

Preserve

Cape May

County


Limit

Lizard Tail Swamp

Preserve

Cape May

County

Bow, Firearm 34 Limit by Acre

Lummis Ponds Preserve

& Lummis II New for 2011!

CumberlandCounty

Bow, Firearm 30/43 Limit by Acre

Willow Grove Lake

Preserve New for 2011!

Gloucester,

Cumberland

County


Limit


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Hunters were required to:

Sign in and out of preserve each time they access the property

Record any wildlife observations and harvest data

Use only designated parking areas and access points

The following activities were not permitted by hunters on TNC preserves:

Use of ATVs

Permanent blinds, stands or structures

Use of screw steps in trees

Killing of animals other than specifically described in the hunting agreement (ex. coyotes)

Trapping or snaring

Hunters also had to follow state hunting rules and regulations regarding permits, bag limits, safety

buffers, etc. In addition, site specific restrictions on baiting for or driving of deer

Measures of Success

In order to evaluate the effectiveness of hunting on each TNC preserve, the following examples of

measures of success will be used:

1. Threat Abatement:At each preserve where hunting is primarily for the purpose of threat abatement, the

following measure of effectiveness will be conducted

Ratio of does to bucks harvested should be greater than 1:1 overall harvest data forthe preserve

Note: at some preserves, the prescribed ratio may be higher to be determined by Stateof New Jersey Deer Management Zones.

This ratio will be determined from reported harvest data. Privilege to hunt to

following year will be partly based on each hunter achieving this doe to buck ratio.

Deer pellet index surveysAt each preserve, transects will be established based on the protocol outlined in (need

ref. to New Zealand paper). These surveys will be conducted by trained staff and/or

volunteers and the data updated annually. Success will be achieved when the index

declines over three consecutive years.

2. Cultural/traditionalAt each preserve two measures will be evaluated for success:

Level of interest as measured by number of applications submittedA lack of cultural interest or need would be indicated by decreasing levels of

hunter applications

Hunter commentsHunters and the hunting community will be encouraged to give us their

feedback and suggestions at every interaction. A decrease in the number of

negative feedback will determine the overall acceptance of this program.


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Deer Hunting data 2011-2012

Preserves

hunted

Acres

hunted

Individual

hunters

Hunting

clubs

Hunting

trips

Hours

hunted

Deer

Harvested

Bucks

harvested

Does

Harvested

Doe

to

buckratio

Deer

seen

Total

6

Total

2800

Total

86

Total

1

Total

439

Total

1165.2

Total

54

Total

11

Total

43

3.9

to 1

Total

757

Total of hunter volunteer work hours completed, There are three pending work parties, total

hours will be added after completion of all work days.

Conclusion:

Threat abatement:

Our goal was to have at least a 1:1 doe to buck ratio, with a 3.9 :1 ratio we far exceeded

our expectations. The deer pellet surveys will be examined after the completion of a few more

years of data collection, this will show if the hunting program is having an effect on our deer

populations.

Cultural/traditional:

More data from next year will be needed to quantify these numbers. After fielding

many phone calls and emails for new hunters wanting to be involved in this program I believewe will exceed our goals for measuring success.

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Deer Pellet Project