Sterilization as an alternative deer control technique: a review
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Human–Wildlife Interactions 6(2):273–282, Fall 2012
Sterilization as an alternative deer
control technique: a review
JASON R. BOULANGER, Cornell University, College of Agriculture and Life Sciences, Department
of Natural Resources, B20 Bruckner Hall, Ithaca, NY 14853, USA jrb69@cornell.edu
PAUL D. CURTIS, Cornell University, College of Agriculture and Life Sciences, Department of
Natural Resources, B13 Bruckner Hall, Ithaca, NY 14853, USA
EVAN G. COOCH, Cornell University, College of Agriculture and Life Sciences, Department of
Natural Resources, B10 Bruckner Hall, Ithaca, NY 14853, USA
ANTHONY J. DENICOLA, White Buffalo Inc., 26 Davison Road, Moodus, CT 06469, USA
Abstract: Burgeoning white-tailed deer (Odocoileus virginianus) populations in suburban
landscapes continue to impact communities and challenge natural resource managers.
Increased deer-related damage to vegetation, ecosystems, and automobiles can exceed the
tolerance of local stakeholders. We provide an overview of the potential efficacy of using surgical
sterilization to help manage populations and conflicts associated with locally overabundant
white-tailed deer populations. We review theoretical and field studies pertaining to deer
sterilization, and provide research priorities to help guide future sterilization efforts. Recent field
studies suggest that sterilization of female deer remains expensive, at approximately $1,000
per surgery. Sterilization may provide an alternative management technique for reducing
suburban deer herds in communities willing to endure the costs of a long-term effort and
where lethal deer removal is unacceptable or impractical. Surgical sterilization is scale-limited
based on the ability to capture and sterilize 80% or more of the female deer in a population
and maintain that proportion of the population treated over time. Overall success will be
greatest for closed or insular deer herds where the effects of immigration can be minimized.
Key words: control, human–wildlife conflicts, Odocoileus virginianus, sterilization, surgery,
white-tailed deer.
Effective control of overabundant white- et al. 2010). Translocation is rarely feasible due
tailed deer (Odocoileus virginianus) populations to cost, limited potential release sites, stress
is of increasing concern to the public and experienced by deer during transport, and risks
wildlife managers. White-tailed deer have of disease transmission (McCullough et al. 1997,
reached unprecedented population levels in Waas et al. 1999, Beringer et al. 2002, DeNicola
some areas of the eastern United States as and Williams 2008). Predator reintroduction
aesthetic preferences for forested suburban also has been proposed, but this method evokes
landscapes have created large areas of habitat safety concerns for many stakeholders because
with low predation risk (Diamond 1992, of the potential for negative human–predator
McCullough et al. 1997). Deer-related damages interactions (Diamond 1992, Warren 2011).
to vegetation, ecosystems, and automobiles in Fertility control has been attempted on
these areas frequently exceed the tolerance of terrestrial and avian wildlife species (Fayrer-
local communities (Decker and Connelly 1989, Hosken et al. 1997, Pech et al. 1997, Hundgen
Diamond 1992, McCullough et al. 1997, Waller et al. 2000, Fagerstone et al. 2010). For example,
and Alverson 1997, Curtis et al. 1998). experimental use of immunocontraceptive
Control of white-tailed deer population vaccines has been attempted on overabundant
densities has conventionally focused on lethal white-tailed deer populations (Fagerstone et
removal (i.e., sharpshooting or hunting). In an al. 2010), and surgical sterilization of coyotes
increasing number of communities, however, (Canis latrans) has been used to protect livestock
lethal management strategies are rejected based (Bromley and Gese 2001) and to control
on legal, safety, or ethical concerns (Decker hybridization with endangered red wolves
and Connelly 1989, Wright 1993, McCullough (Canis rufus; Fredrickson and Hedrick 2006,
et al. 1997), fostering interest in alternatives, Roth et al. 2008). Many studies agree, in theory,
including translocation, contraception (McShea that fertility control might reduce and maintain
et al. 1997, Warren 1997, Malcolm et al. 2010), some animal populations at desired levels
and surgical sterilization (MacLean et al. 2006, (Sturtevant 1970, Knipling and McGuire 1972,
Merrill et al. 2006, Boulanger et al. 2009, Gilman Chambers et al. 1999, Twigg and Williams 1999).274 Human–Wildlife Interactions 6(2) Implementation with larger mammals, such as the need for repeated treatments (Kirkpatrick deer, however, may be difficult, and published et al. 1997, Rudolph et al. 2000, Curtis et al. assessments of the feasibility of managing these 2002, Merrill et al. 2003). GonaCon™ (National populations via fertility control have varied Wildlife Research Center, Fort Collins, Col.), widely (Seagle and Close 1996, Barlow et al. a gonadotrophin-releasing hormone (GnRH) 1997, Hobbs et al. 2000, Rudolph et al. 2000). immunocontraceptive vaccine, is currently Porter et al. (2004) suggest that female suburban registered with the U.S. Environmental white-tailed deer possess behavioral attributes, Protection Agency for use on female white- such as smaller home ranges (when compared tailed deer 1 year of age or older (Fagerstone et to their rural counterparts), limited seasonal al. 2010). In a recent field study, a single shot of movements, and high site fidelity that may GonaCon™ was administered to female white- enhance feasibility of culling or contraception tailed deer; 88% and 47% of treated deer did not programs at smaller geographic scales (5 to 10 become pregnant during the first and second km2), but the authors warn that dispersal may years, respectively (Gionfriddo et al. 2009). complicate management. Some studies suggest Although previous model-based (Barlow that fertility control may be more effective than et al. 1997, Hobbs et al. 2000, Merrill et al. culling because treated individuals are able to 2003) and field studies (MacLean et al. 2006) contribute to resource limitation and density- have suggested that sterilization of female dependence in reproduction (Knipling and deer has the potential to regulate or reduce McGuire 1972, Boone and Weigert 1994). Other overabundant ungulate populations, the studies suggest that culling is more effective efficacy and practicality of this technique has and must be included as part of a fertility not been established. Despite this fact, several control program (Nielsen et al. 1997, Hobbs experimental sterilization studies have been et al. 2000). The Wildlife Society’s (2008) final or are being conducted to help control deer position statement on wildlife fertility control overabundance. With the increase in research suggests that such application may potentially and a continued demand for nonlethal deer have use in urban or suburban locales or other control options, timely information will better areas with little immigration and where lethal inform researchers, managers, and stakeholders deer control (e.g., hunting) is restricted. who may be considering this technique. We Duration of fertility control can vary from review theoretical and field studies pertaining transient (i.e., temporary) to permanent (e.g., to deer sterilization and provide research surgical sterilization; Merrill et al. 2003). Early priorities to help guide future sterilization studies in deer contraception using steroids efforts. Because surgery is currently the only reported limited success, but concerns over reliable means to permanently sterilize female secondary consumption by nontarget animals deer (MacLean 2006), we focus our review on (e.g., scavengers) and humans limited this type this technique as a means to manage locally of treatment (Turner et al. 1992). In a recent overabundant white-tailed deer herds (Figure study, intrauterine devices that were implanted 1). prior to the breeding season prevented pregnancy in 6 of 8 female deer during a 2-year Theoretical application of period (Malcolm et al. 2010). While progress sterilization has been made with immunocontraceptive Modeling studies have suggested vaccines and their safety, continued refinement that sterilization may reduce ungulate in their development and delivery systems overabundance (Barlow et al. 1997, Hobbs et is still needed (Cowan et al. 2003). Moreover, al. 2000). Boone and Wiegert (1994) identified further acceptance of fertility control by the sterilization of deer as a viable alternative public and natural resources agencies may to lethal control when used to supplement be necessary (Fagerstone et al. 2002, 2010). hunting pressure. Seagle and Close (1996) Immunocontraception may be unsuitable in examined the effects of various sterilization some communities because of prohibitive proportions, and suggested that treating at long-term costs, uncertainty in identifying least 50% of breeding-age females was expected treated individuals in free-ranging deer, and to reduce white-tailed deer populations.
Deer sterilization • Boulanger et al. 275
reliably predict outcomes; (3) no behavioral
changes in deer post sterilization; and (4)
deer populations that are closed. In reality,
managers will not likely have control over the
difficulty associated with deer capture. For
example, males and recaptured sterilized deer
may confound trapping efforts. Moreover, a
lack of access to suitable capture sites could be
an obstacle to reaching a minimum proportion
of females (Rudolph et al. 2000). The second
assumption of deterministic models is
problematic because of the complex effects of
environmental and demographic stochasticity.
Figure 1. Adult female white-tailed deer undergoes In northern climates, for example, periodic
surgical sterilization at the Cornell University Hospi- mild winters lead to periodic increases in
tal for Animals.
productivity, which could intermittently limit
Even with higher rates, however, a 5- to 10- the effectiveness of controlling deer populations.
year planning horizon was necessary to see In the third assumption, a sterilized deer may
reductions in population size (Seagle and become trap-averse or exhibit trap affinity to
Close 1996). Hobbs et al. (2000) demonstrated baited stations. Lastly, the assumption of closed
that fertility control of varying duration could populations suggests that sterilization would
regulate ungulate populations under some be effective if birth rates were lowered. In an
circumstances, but they evaluated models over open population, however, recruitment consists
infinite time horizons and did not consider the of both in situ recruitment (local births) and
relative efficiency for fixed-time horizons. Thus, immigration, while sterilization only reduces
communities experiencing deer damage had births from female deer. Modelling by Merrill
little information on which to predict success et al. (2006) accounted for stochasticity and
of fertility control programs within 5- or 10- demonstrated a low probability of sterilization
year timelines, scales over which stakeholder alone as a successful management technique in
decisions are often made. an open deer population.
Unlike previous studies, modeling by Merrill Sterilization will likely be more successful in
et al. (2003) considered impacts of survival and a closed or insular population of white-tailed
fertility rates of all gender classes, uncertainty deer. In a truly closed population, however, N
in birth and survival rates across all sterilization may be constant, implying that birth and death
levels, and the relationship between annual rates are equal, which is an unlikely scenario
sterilization rates and the expected time to for most deer populations. With immigration,
specific population reduction. Merrill et al. the absolute number of deaths must be greater
(2003) determined that a hypothetical, closed than births and new immigrants to reduce
white-tailed deer population may be reduced deer abundance. In some deer populations,
by 30 to 60% in 4 to 10 years if 25 to 50% of the number of deaths may be insufficient to
the fertile females could be sterilized annually. outnumber immigrants. Thus, lowering birth
However, assuming high birth and survival rates via sterilization might slow growth, but
rates typical for many suburban deer herds, a it is unlikely to reduce the population unless
75% reduction would require approximately 7 immigration rates are low or mortality rates
years at an 80% annual sterilization rate (Merrill (e.g., deer–vehicle collisions [DVCs]) are
et al. 2003). high. Merrill et al. (2006) note that in closed
Merrill et al. (2006) noted that previous populations the only new annual recruits are
modeling which tested the plausibility fawns with minimal reproductive capacity.
and efficacy of sterilization as a potential In open populations, however, increased
management strategy relied on several sterilization efforts may be required because
assumptions: (1) complete control in sterilizing new immigrants include adult females that
deer in a population; (2) deterministic models can reproduce at maximum capacity. However,276 Human–Wildlife Interactions 6(2)
immigration from an expanding deer population effective in preventing pregnancies, there are
may be slow because adult female white-tailed few published accounts of its implementation
deer tend to be highly philopatric (Porter et in free-ranging populations. Frank and Sajdak
al. 1991, 2004, Rudolph et al. 2000, Kilpatrick (1993) reported that sterilization slowed
et al. 2001). Porter et al. (2004) demonstrated population growth of a white-tailed deer
the importance of considering closure when population on the grounds of the Milwaukee
using fertility control to manage localized County Zoo (Milwaukee, Wis.). From 1990
suburban deer populations, and suggested to 1992, 14 (8 male and 6 female) deer were
that emigration may be another complicating sterilized; the population was reduced to 2
factor. Merrill et al. (2006) suggest that reducing animals by March 1993 (Frank and Sajdak 1993).
survival rates for reproductive-age females During the time of this study, the cost of surgical
is the most effective means for reducing deer procedures (e.g., drugs, materials, veterinarian
populations and that controlling immigration and zoo personnel salary) for bucks and does
may be more effective than controlling birth ranged from approximately $46 to $83 and $94
rates in suburban deer herds. to $210, respectively.
The city of Highland Park, Illinois, like
Field studies in surgical other suburban areas with unhunted deer
sterilization populations, was experiencing overabundance
Research pertaining to surgical sterilization and a concomitant increase in negative human–
as a technique to control deer populations deer interactions (Skinner 2007). The deer
is still in its infancy. Vasectomy was used to density in Highland Park was estimated to be
permanently sterilize male white-tailed deer 4 to 5 deer/km2 (MacLean et al. 2006). In 2002, a
(Frank and Sajdak 1993). Sterilization of male program was implemented in Highland Park to
deer, however, is unlikely to be effective due to investigate the long-term effects of permanent
their polygynous mating and the effort involved female sterilization on free-ranging white-
in treating nearly all males (Merrill et al. 2003). tailed deer behavior and abundance (Maclean
Thus, control of deer population growth is et al. 2006). In that study, 67 female deer were
more practically attained by managing fertility sterilized under field conditions using a mobile
of females (Porter et al. 2004). Techniques surgical unit and tubal ligation (n = 64), tubal
used to sterilize female deer have included transection (n = 2), and ovariohysterectomy
laparotomy or laparoscopy with tubal ligation, (n = 1) surgeries. Two years post-sterilization,
tubal transection, or ovariohysterectomy no sterilized does were observed with fawns.
(Frank and Sajdak 1993, MacLean et al. 2006). Researchers concluded that the surgical
MacLean et al. (2006) favored laparotomy over procedures provided effective sterilization with
laparoscopic procedures for logistical reasons low mortality rates in suburban deer (Maclean et
and to avoid the risk of damaging the uterus al. 2006). In this study, however, it was reported
of pregnant females. Adult females with an that sterilized females had significantly higher
abundance of omental fat may also hinder deer–vehicle collision mortality rates when
laparoscopic procedures (Frank and Sajdak compared to a control group of fertile females;
1993). Unlike surgical procedures that remove greater movement of non-gravid females was
ovaries, tubal ligation prevents reproduction suggested to be the cause (Skinner 2007, Gilman
without altering normal hormonal function, et al. 2010).”
which results in repeated estrus cycling during Modeling suggested that surgical sterilization
subsequent years. Pregnant does receiving could control the deer population to the desired
tubal ligation surgery will carry their current goal of 2 deer/km2 by treating 32% of females
fetuses to term if captured in winter, but will annually, albeit with long-term maintenance
not become pregnant thereafter. Warlock (1997) (i.e., 9.5 years; Skinner 2007). The average cost
studied the effects of tubal ligation on behaviors per deer sterilization, including capture time,
of a captive white-tailed deer population and was >$1,000 (N. Mathews et al., University of
suggested that sterilization was not detrimental Wisconsin, unpublished data). The direct cost
to treated does. for the veterinarian’s work was approximately
While surgical sterilization of female deer was $750 per deer, including $150 in drugs per deer
and veterinarian’s time.Deer sterilization • Boulanger et al. 277
The city of Town and Country, Missouri, a to estimate deer abundance during the study
suburb of St. Louis, comprised of suburban and (Curtis et al. 2009). Deer population estimates
commercial development, parks, and other open and 95% confidence intervals for 2000, 2002,
spaces, implemented a surgical sterilization and 2004 were 124 (104, 148), 157 (115, 214),
and sharpshooting program from November to and 87 (67, 113), respectively (Boulanger et
December 2009 in response to burgeoning deer al. 2009, Curtis et al. 2009). Sterilization alone
populations (A. J. DeNicola, White Buffalo Inc., was unlikely the sole cause of the reduction
unpublished data). Twelve days of fieldwork in deer numbers at Cayuga Heights. Based on
were required to capture and sterilize 100 does, Merrill et al. (2003, 2006), a response was not
utilizing a mobile surgical trailer and part- expected, as the sterilized fraction of females
time veterinary surgeon. Methods followed was below suggested thresholds for impact,
those from Highland Park, Illinois (MacLean and enough time may not have elapsed for an
et al. 2006), except that ovariectomies were effect to be discerned in population abundance.
performed through mid-line incisions (not Moreover, the harsh winter of 2002–2003 may
lateral incisions or tubal ligations). Program have decreased survival rates. In that season,
staff expended 690 person-hours for the capture there was 82 cm more snow than the long-term
and surgical sterilization efforts. Capture effort average, ranking sixth for the highest recorded
(time to drop-net or dart and locate deer) was snowfall in Ithaca since 1893. Moreover, there
449 person-hours. Surgery effort (i. e., time to were 32 more days with snow on the ground
bring deer from the location of recumbency to than the long-term average, ranking eighth for
surgery trailer, conduct the ovariectomy, and most snow on the ground (National Oceanic
return to point of capture) was 241 person- and Atmospheric Administration, Northeast
hours. The approximate cost per deer sterilized Regional Climate Center at Cornell University,
in the Town and Country program was $960 Ithaca, New York). Sterilization costs were
per deer (A. J. DeNicola, White Buffalo Inc., >$1,000 per deer during the study, which
unpublished data). included $550 for pharmaceutical supplies,
anesthesia, equipment sanitizing, and laundry,
Surgical sterilization in Ithaca, and $525 labor costs to capture and mark
New York each deer. Cornell University’s Large Animal
The residents of Cayuga Heights, an affluent Hospital donated surgery expenses for resident
suburban community in the town of Ithaca, surgical training (Boulanger et al. 2009).
New York, were experiencing an increasing Information from the Cayuga Heights study,
population of white-tailed deer and associated in part, has led to continued research of surgical
impacts (Chase et al. 1999, Shanahan et al. sterilization on Cornell University (Ithaca, New
2001). In surveys of Cayuga Heights residents, York) lands to supplement a controlled deer
respondents expressed concern regarding hunting program (Boulanger et al. 2009). For
DVCs, damage to plantings, and Lyme disease this 5-year study, Cornell lands were divided
(Shanahan et al. 2001). Over 80% of respondents into 2 zones: a core campus area (446 ha)
reported damage to trees, shrubs, and flower where sterilization was the main management
gardens and 23 to 25% reported experience technique and outlying areas (582 ha) containing
with deer-related auto accidents (Shanahan agricultural fields, woodlots, and natural areas
et al. 2001). In response to these impacts, where hunting has been permitted for decades
Cayuga Heights implemented a surgical (Boulanger et al. 2009). The primary objective
sterilization program to reduce the population for the core campus zone was to reduce deer
of overabundant deer (Boulanger et al. 2009). damage to unique plant collections and research
Between 2002 and 2004, 24 female deer were plots while minimizing safety risks associated
surgically sterilized via tubal ligation (n = 8), with deer. We continue to monitor complaints
ovariectomy (n = 15), and hysterectomy (n=1). about deer damage to plants, reported DVCs,
Captured deer were fitted with numerical and deer abundance. The primary objective for
ear tags, radio collars, and infrared-triggered the hunting zone was to reduce deer damage
cameras and Program NOREMARK (White to agricultural fields and natural areas through
1996) with Bowden’s ratio estimator was used an intensely managed Earn-a-Buck hunting278 Human–Wildlife Interactions 6(2)
program (Ferrigno et al. 2002, Boulanger et population, then sterilization should not be
al. 2009, Van Deelen et al. 2010), focusing on implemented due to cost and lack of efficacy.
the increased harvest of female deer. Closer Ultimately, factors that would influence efficacy
to campus, archery hunting is the primary of sterilization at the population level include
approach; use of firearms is permitted in more the proportion of females that could be treated,
distant areas (Boulanger et al. 2009). failed surgeries, compensatory responses (e.g.,
Infrared-triggered camera methods outlined increased survival of treated females and
by Curtis et al. (2009) were used to estimate increased reproduction in untreated females),
93 (95% CI = 84,102; ~21 deer/km2) deer on and mortality and dispersal rates.
the Cornell University campus in March 2009 Controversy over lethal versus nonlethal
(Boulanger et al. 2009). From October 2007 means to control deer populations in urban
through March 2009, 58 sterilization surgeries and suburban areas continues to spark interest
were performed on white-tailed deer captured in alternative fertility control methods, such
on the Cornell campus; 11 deer in this group as surgical sterilization. While tubal ligation
received ovariectomies, and 47 deer received has been safely used for urban white-tailed
tubal ligations (Boulanger et al. 2009). The deer, Skinner (2007) found increased vehicle
approximate cost per deer sterilized in this mortality for sterilized female deer, and
study was >$1,000, which included expendables, Gilman et al. (2010) suggested increased
such as pharmaceutical supplies, anesthesia, non-maternal movement as a possible cause.
equipment sanitizing, and laundry, as well as These collateral impacts may be confounding
labor costs for capture and marking; surgery to biologists attempting to reduce DVCs and
expenses were donated for Cornell veterinary use these data to assess management effects.
staff and resident surgical training (Boulanger Paradoxically, this increased mortality may
et al. 2009). Deer that received ovariectomies benefit wildlife managers trying to reduce deer
were not subsequently observed with fawns; population levels, but it may not end the debate
however, 1 tubal ligation surgery failed, over lethal control. Conversely, Rutberg and
resulting in parturition. Naugle (2008) found no correlation between
deer treated with immunocontraceptives and
Discussion DVCs, and suggested that any added behavior
Deer abundance may be managed with effects caused from treatment are likely to be
surgical sterilization in specific situations and small and offset by the benefits of population
may be more realistic at smaller, local scales management. The relationship between
(e.g., 5 to 10 km2). For example, Frank and sterilization, deer densities, and DVCs deserves
Sajdak (1993) demonstrated a reduction in deer further investigation.
numbers because they started out with a small Results from modeling do not bode well for
herd of deer. Clearly, sterilization efforts will the feasibility of surgical sterilization as the
be more difficult and costly in a community sole tool for reducing open deer populations,
suffering the effects of overabundance from especially if immigration offsets decreases
hundreds of deer over a large geographic range. in population size (Merrill et al. 2006). With
Communities ready to commit to sterilization the exception of some gated residential
control should be prepared for a long-term communities and government reservations,
effort (e.g., ≥10 years). Based on Merrill et al. for example, most communities experiencing
(2003), we recommend that >80% of female impacts will have open populations of white-
deer be targeted for sterilization surgery due tailed deer. Sterilization programs that include
to the white-tailed deer’s high survival and an initial effort of lethal control may be more
reproductive rates in suburban landscapes. successful in reducing overabundant herds.
However, we recognize that treating such a Once a population is reduced, efficacy of
large proportion of deer is not feasible for sterilization may be greater than lethal control in
some communities. If a longer timeline is maintaining desired population levels (Merrill
possible, a community may consider treating a et al. 2003). Also, fewer deer will need to be
smaller proportion of deer, but if a community surgically treated, which may lower overall
cannot initially target at least 50% of the local program expenses. If a combined-methodsDeer sterilization • Boulanger et al. 279 program is chosen, we recommend that short- and long-term differences between these surgeries be performed first, as capturing deer fertility control methods. is more difficult than sharpshooting or hunting. Research is needed to quantify the effects Deer that are most susceptible to capture can be of surgical sterilization. For example, female sterilized, and the less accessible deer may be deer released from the energetic costs of targeted by lethal techniques. Further research reproduction may experience higher survival is needed to assess the effects of immigration rates. Also, female deer receiving tubal ligation and the use of lethal control as a complement surgery will experience repeated estrous cycles to sterilization. during winter and spring. Consequently, Surgical sterilization as a management option females may attract more bucks into their home may not be as cost effective as culling (Curtis et range, which may increase DVCs or rubbing al. 1998). Start-up expenses, drugs, surgeries, damage to valuable ornamental plantings. In and deer capture comprise just a few of the addition, the hormonal or physiological effects costs associated with this technique (Merrill et of surgical ovariectomies remain unclear. al. 2003). Boone and Wiegert (1994) suggested Initial field studies using surgical sterilization that effective applications may require a large demonstrated the potential for reducing number of animals to initially be sterilized, suburban deer herds, albeit with a substantial demanding high start-up costs. Initial efforts initial effort and cost relative to some types of would need to be sustained for several years and lethal control. While progress has been made then relaxed as the number of sterilized females with contraception, we suggest long-term cost increased (Nielsen et al. 1997). Capture costs also savings when using surgical techniques that will be related to deer behavioral responses and preclude the need for deer recapture. Should access to adequate capture sites. Trap-averse communities be willing to endure the costs of deer would result in a lower recapture rate and a long-term effort, surgical sterilization may be allow for unsterilized animals to be captured, a viable option for reducing deer populations while trap affinity of deer at baited capture sites where lethal deer removal is impractical. In would increase costs (Merrill et al. 2003). Recent addition, such applications will be scale-limited reports suggest that actual costs of surgical based on the ability to capture and maintain a sterilization will be approximately $1,000 per high percentage of sterilized deer each field deer. The cost per deer, however, is not constant. season. Additional field research is needed to Initial captures may be cost efficient, but cost measure immigration and emigration rates per deer may increase exponentially for the for suburban deer herds, as this will affect last percentile of targeted deer, which are the the effectiveness and time scale for proposed most difficult to catch (Rudolph et al. 2000). fertility control programs. Direct comparisons of cost among studies are difficult because of differences in year of study, Acknowledgments sterilization techniques, capture techniques, We dedicate this manuscript to John A. staff time, and number of deer treated. Merrill (1980–2010). Surgical sterilization currently may be more cost effective than transient fertility control Literature cited techniques, such as immunocontraceptive Barlow, N. D., J. M. Kean, and C. J. Briggs. 1997. vaccines (e.g., GonaCon™) that are not 100% Modeling the relative efficacy of culling and efficacious, and require booster shots. Curtis sterilization for controlling populations. Wildlife et al. (1998) estimated minimum costs ($296 to Research 24:129–141. $703 per deer) to capture and treat a female deer Beringer, J., L. P. Hansen, J. A. Demand, J. with contraceptive vaccines in Irondequoit, Sartwell, M. Wallendorf, and R. Mange. 2002. New York. While these estimates were lower Efficacy of translocation to control urban deer than current costs for surgical sterilization, the in Missouri: costs, efficiency, and outcome. vaccines required subsequent booster shots for Wildlife Society Bulletin 30:767–774. each treated deer. As contraceptive vaccines Boone, J. L., and R. G. Wiegert. 1994. Modeling and surgical sterilization techniques improve, deer herd management: sterilization is a viable cost-benefit analyses will be needed to discern option. Ecological Modeling 72:175–186.
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JASON R. BOULANGER (photo unavailable) search Council post-doctoral fellowship with Bob
is the deer research and management program coor- Ricklefs (University of Pennsylvania), followed by a
dinator and an extension associate at Cornell Univer- second post-doc with Jim Nichols (Patuxent Wild-
sity. He received a B.S. degree in natural resources life Research Center). He took a position as an as-
from the University of Vermont (1995), an M.S. de- sistant professor in the Chair for Wildlife Ecology at
gree in wildlife and fisheries sciences from South Simon Fraser University (Burnaby, British Columbia,
Dakota State University (2001), and a Ph.D. degree Canada) before joining the Department of Natural
in wildlife science from Cornell University (2007). He Resources at Cornell University in 1998. He is also a
was a wildlife specialist with USDA/Wildlife Services member of the graduate fields of ecology and evolu-
and a wildlife biologist with the New York State Ani- tionary biology, toxicology, and computational biolo-
mal Health Diagnostic Center before joining the De- gy. He is also a research fellow in the Cornell Institute
partment of Natural Resources at Cornell University of Computational Sustainability. His current research
in 2007. His research and extension programs have focuses on the development and application of novel
focused on human–wildlife conflicts in agricultural and robust statistical approaches to key questions in
and suburban landscapes. His other research inter- theoretical and applied ecology.
ests include wildlife ecology, wildlife diseases, and
human dimensions of wildlife. He is a certified wildlife ANTHONY J. DENICOLA (photo unavail-
biologist with The Wildlife Society. able) is president of White Buffalo Inc., a nonprofit
research organization dedicated to conserving eco-
PAUL D. CURTIS (photo unavailable) is an as- systems through wildlife population control. He re-
sociate professor and extension wildlife specialist at ceived a B.S. degree in biology from Trinity College
Cornell University, and he has coordinated the wildlife of Hartford, Connecticut (1988), an M.S. degree from
damage management program there during the past the Yale School of Forestry and Environmental Stud-
16 years. He received a B.S. degree from West Vir- ies (1990), and a Ph.D. degree in wildlife ecology
ginia University (1978), an M.S. degree from Colora- from Purdue University (1996). He has coordinated
do State University (1981), and a Ph.D. degree from numerous suburban deer management and research
North Carolina State University (1990). His research programs and has been involved with nearly all the
interests include wildlife damage management in ur- world’s largest ungulate eradication programs. He is
ban and agricultural landscapes, wildlife fertility con- a member of the National Wildlife Control Operators
trol, and resolving community-based wildlife issues. Association, the Society for Conservation Biology,
He serves as faculty advisor for the Cornell University and The Wildlife Society. He holds research affiliate
student chapter of The Wildlife Society, and is a for- positions with Trinity College, the Denver Zoological
mer chair of the TWS-Wildlife Damage Management Foundation, and Rutgers University. His professional
Working Group. interests are technical and behavioral and ecological
approaches to wildlife damage control, wildlife repro-
ductive control, and control of introduced vertebrate
EVAN G. COOCH (photo unavailable) is associ- species.
ate professor of population biology and wildlife ecol-
ogy at Cornell University. He received a B.S. degree
in biology and chemistry from St. Lawrence Univer-
sity of Canton, New York (1981), and a Ph.D. degree
in evolutionary and population ecology from Queen's
University of Kingston, Ontario, Canada (1990). He
completed a Natural Sciences and Engineering Re-You can also read
