2008 NORTHEASTERN NATURALIST 15(3):431–444
Home Range and Movement of Blanding’s Turtles
(Emydoidea blandingii) in New Hampshire
Robin J. Innes1,3, Kimberly J. Babbitt1,*, and John J. Kanter2
Abstract - Emydoidea blandingii (Blanding’s Turtle) is a Species of Special Concern
in New Hampshire, yet it has received little research attention. As part of a broader
study to establish conservation and management guidelines for this species, we radiotagged
18 Blanding’s Turtles to determine home range and movement patterns within
two study areas of southeastern and central New Hampshire from 2000–2002. Mean
daily movement of female turtles peaked in June coincident with nesting, whereas
movement of males peaked in August and September coincident with an increase in
mating activity. Median adaptive kernel home range (HR) and core range (CR) estimates
for turtles in central New Hampshire (HR = 12.5 ha, CR = 3.1 ha) were larger
as compared to southeastern populations (HR = 3.7 ha, CR = 1.6 ha). This difference
could not be readily explained by characteristics of the turtles, such as age, size, or
sex. New Hampshire populations of Blanding’s Turtles exhibit intermediate home
range sizes compared to other parts of the species distribution. Forty-five percent of
turtles exhibited multimodal location distributions in core range estimates. Mating
and estivating turtles were always found within their core range area, whereas turtles
occasionally traveled outside of core ranges to seek suitable overwintering sites.
Thirty-eight percent of turtles used the same overwintering habitat for 2 consecutive
winters. Location-specific information regarding key nesting and overwintering
areas may be important to the conservation of the species.
Introduction
Emydoidea blandingii (Holbrook) (Blanding’s Turtle) is a semi-aquatic
species whose primary range is in the Great Lakes region and midwestern
United States, with disjunct populations occurring in portions of Massachusetts,
New Hampshire, Maine, New York, and Nova Scotia, Canada (Ernst
et al. 1994). Blanding’s Turtle populations in New Hampshire have received
little research attention. There is concern that Blanding’s Turtle populations
in New Hampshire may exist in very low densities and that the species is declining
due to a variety of factors including habitat loss and fragmentation,
and increased road building and consequent increases in road kill. The range
of the Blanding’s Turtle overlaps with the four counties in New Hampshire
having the fastest growing human population (Society for the Protection of
New Hampshire Forests 2005).
The status of Blanding’s Turtles in New Hampshire is best described
as poorly known. Its classification as a Species of Special Concern may
1Department of Natural Resources, University of New Hampshire, Durham, NH
03824. 2New Hampshire Fish and Game Department, Concord, NH 03301. 3Current
address - Wildlife, Fish, and Conservation Biology Department, University of California,
Davis, CA 95616. *Corresponding author - kbabbitt@cisunix.unh.edu.
432 Northeastern Naturalist Vol. 15, No. 3
underestimate the conservation and management needs of this species, as the
Blanding’s Turtle is classified as Threatened (Massachusetts) or Endangered
(Maine) in adjacent states where it has received greater research attention
(e.g., Grgurovic and Sievert 2005, Joyal et al. 2000). Further, several lifehistory
features, including delayed sexually maturity (Congdon and van Loben
Sels 1991; Congdon et al. 1983, 1993; Gibbons 1968; Graham and Doyle
1977; MacCulloch and Weller 1988, Petokas 1986; Ross 1989), low recruitment
caused by low fecundity, high juvenile and egg mortality, and high levels
of egg and nest failure (Congdon et al. 1983, Herman et al. 1995, Linck and
Moriarty 1997, Petokas 1986, Power 1989, Ross 1989, Ross and Anderson
1990, Standing et al. 2000) enhance the vulnerability of this species to the
effects of habitat loss and degradation, and limit their ability to recover from
high levels of additive mortality caused by anthropogenic factors. Further,
cumulative evidence suggests that factors that increase adult mortality are
the most significant threat to this species (Congdon and van Loben Sels 1991;
Congdon et al. 1983, 1993; Doak et al. 1994; Heppell et al. 1996; Herman
1997; Iverson 1991). More than 358,000 people are projected to move into
New Hampshire between 2000 and 2025 (Society for the Protection of New
Hampshire Forests 2005), increasing the amount of suburban development,
roads, and traffic, all of which threaten the future of this species.
Understanding the home range and habitat use patterns are fundamental to
guiding appropriate land management and conservation approaches. As part of
a broader effort to determine the best conservation management strategies for
the Blanding’s Turtle in New Hampshire, we conducted a trapping and radiotelemetric
study to determine the home range, movement patterns, and habitat use
of Blanding’s Turtles. We used the information to address the following objectives:
1) determine space use (i.e., home range) of Blanding’s Turtles throughout
the year, and 2) evaluate how space use is influenced by turtle movements
and activity (i.e., nesting, mating, estivation, and overwintering).
Methods
We studied Blanding’s Turtles during their active season (April–October)
from 2000 to 2002. We examined the home range and movement patterns of
Blanding’s Turtles from six sites (wetland-upland complexes) in two areas
of New Hampshire separated by 60 km (Fig. 1). Three sites were located
in the southeastern corner of New Hampshire in the towns of Newmarket
and Lee within Strafford and Rockingham counties (hereafter Strafford).
Three additional sites were located in central New Hampshire, in the towns
of Weare and Dunbarton within Merrimack and Hillsborough counties
(hereafter Hillsborough). Wetland habitat types were defined by geographic
information system data layers provided by the New Hampshire GRANIT
database. Wetland habitat types within the study sites included freshwater
marsh, wet meadows, scrub-shrub and forested wetlands, permanent ponds,
vernal pools, and riparian and lacustrine habitats. The upland matrix included
mixed deciduous-coniferous forests, primarily deciduous woodlands, and
2008 R.J. Innes, K.J. Babbitt, and J.J. Kanter 433
scattered open lands, including agricultural fields and active and abandoned
sand and gravel pits. Sites were located in both rural and suburban areas.
We captured Blanding’s Turtles with baited, nylon hoop traps (2 m long x
0.8 m dia; 5-cm mesh), opportunistically by hand, and during road surveys to
and from study sites. Hoop traps were set in wetlands from April to October
and checked every 24 to 48 hours. The number of hoop traps placed in each
wetland ranged from one to six depending on wetland size. We uniquely
marked all captured Blanding’s Turtles by notching the marginal scutes of
the carapace (Cagle 1939). We weighed turtles to the nearest 5 g, measured
straight-line carapace and plastron width and length with calipers to the
nearest 1 mm, and estimated the age of turtles by counting plastral humeral
laminae (Condgon and van Loben Sels 1991, Germano and Bury 1998,
Graham 1979, Innes et al. 2005). Sex was determined in adults by plastral
concavity and distance of the cloacal opening from the carapacial margin
(Ernst et al. 1994, Graham and Doyle 1977).
Figure 1. Map of New Hampshire
indicating the current
known distribution of Blanding’s
Turtles (Emydoidea
blandingii) based on records
from the Reptile and Amphibian
Reporting Program
(RAARP) at the Nongame and
Endangered Species Program,
New Hampshire Fish and
Game Department (light gray
shaded areas). Areas shaded
in dark gray indicate study areas
(Hillsborough County and
Strafford County).
434 Northeastern Naturalist Vol. 15, No. 3
We fitted 18 adult Blanding’s Turtles with 11-g radio transmitters
with whip antennas (Advanced Telemetry Systems, Model LTC-7PN), by
attaching the transmitter package to the anterior portion of the carapace
using epoxy putty as a base and clear waterproof epoxy as a coating. The
transmitter package weighed about 66 g (n = 18, 5.1% of body weight, mean
= 1294 g, range = 825 to 1725). We released turtles near the point of capture
within 24 hours of capture. To minimize temporal autocorrelation, we did
not locate individuals more than once in any 48-hour period; we located individuals
approximately three times per week between 0700 and 1900 hours.
Locations were determined by homing (Samuel and Fuller 1996), using a
hand-held receiver (Communications Specialists, Inc., Orange, CA; Model:
R-1000) and Yagi antenna. We recorded locations using a hand-held geographical
positioning system unit (Model: Garmin 12, Garmin International,
Inc., Olathe, KS) accurate to within 10 m.
We conducted home range analyses on radio-tagged individuals when
the following conditions were met: 1) the individual was determined to
have the minimum number of sequential radio locations required to reach an
asymptote in home range size (Kenward 2001), and 2) the radiotelemetric
duration for the individual encompassed at least 5 months of activity, thus
representing the active season of Blanding’s Turtle in New Hampshire. Several
Blanding’s Turtle home ranges examined in preliminary analyses had
more than one area of intensive use (i.e., multimodal). Therefore, we chose
the adaptive kernel method (ADK) to estimate home range because it relies
on probability densities and is a better technique for accurately determining
home range size in animals exhibiting bimodal distributions (Aebischer et
al. 1993, Worton 1989). We also used the minimum convex polygon method
(MCP) to facilitate comparison with previous studies (Mohr 1947). Extended
trips, such as those associated with nesting females, were excluded from
home range estimates and evaluated separately (Rowe and Moll 1991).
We calculated home range and average daily distance traveled using
the CALHOME Home Range Analysis Program (Kie et al. 1996). For individuals
tracked multiple years, we selected one year randomly for each
individual for analyses. We estimated home ranges and core ranges (a.k.a.,
activity centers) using 95% and 70% of all radio locations, respectively, by
omitting outlying locations (Anderson 1982; White and Garrott 1990; Worton
1989, 1995). The number of polygons comprising the core range was
calculated in CALHOME using ADK. In addition, ADK utilized a grid of 50
x 50 cells overlaid onto the dataset and an optimum bandwidth (smoothing
parameter), following the methods of Piepgras and Lang (2000). A grid of
50 x 50 cells is the maximum allowable by CALHOME, and results in the
smoothest fit to the data (Kie et al. 1996). For radio-tagged turtles having
a small home range (less than 3.5 ha), it was not possible to use a grid of 50 x 50
cells. In these cases, CALHOME selected the optimum grid cell size and
bandwidth to achieve the lowest least-squares cross-validation score (Kie
et al. 1996). To determine if movement habits changed over the tracking
2008 R.J. Innes, K.J. Babbitt, and J.J. Kanter 435
period, we computed distances between successive locations and estimated
mean distance traveled per day during a month, assuming a constant rate of
movement in a straight line between locations.
We analyzed turtle movements in the context of monthly activities based
on: 1) change in overall activity (i.e., decrease in basking, nesting; increase in
estivating, mating); 2) change in average movement distance; and 3) apparent
shift in habitat-type used (i.e., to overwintering habitat). Gross habitat shifts
within hydrologically connected wetlands (inter-habitat shifts) and between
isolated wetlands (inter-wetland shifts requiring overland movement) were
examined. We identified shifts by a change in the most dominant habitat used.
Shifts were generally easy to recognize, as daily movements within a habitat
type were generally small, whereas inter-habitat shifts and inter-wetland
shifts were often associated with larger and often sudden movements (i.e.,
large short-term movement preceded and followed by little movement). Small
movements alongside transitional zones between wetland habitat types were
sometimes apparent. Movements associated with nesting, estivation, mating,
and overwintering were examined for differences between these activity
sites and core range areas. Turtles were assumed to be inactive and potentially
estivating if 3 or more consecutive radio-locations (5 or more days) occurred
within the same location. Estivation as defined here is a period of inactivity
coinciding with decreasing water availability in the late summer and fall, and
is a behavior that has been observed to occur terrestrially (e.g., Rowe and Moll
1991) and aquatically (e.g., Ross and Anderson 1990) in Blanding’s Turtles.
Overwintering movements were associated with a lull in activity at the end of
the active season in October and November.
Results
We captured 31 Blanding’s Turtles in Strafford (17 males, 11 females,
3 juveniles), and 9 Blanding’s Turtles (6 females, 3 males) in Hillsborough
throughout the course of the study. We radio-located 18 turtles during the active
period from 2000 to 2002: 1 juvenile (PL = 158 mm, 10 years old), 6 adult
males, and 3 adult females in Strafford, and 3 adult males and 5 adult females
in Hillsborough. Of these adults, 11 radio-tagged turtles were included in analyses.
Three radio-tagged turtles were located at Hillsborough at one study site,
and 8 radio-tagged turtles were located at Strafford at 3 study sites. The juvenile
radio-tagged turtle in Strafford was retained for comparative purposes
since the home range ecology of Blanding’s Turtle in this age class is generally
lacking (Piepgras and Lang 2000). The number of locations obtained for
radio-tagged animals used in analyses averaged 52 (range = 37–65 locations)
and spanned 5 to 7 months of activity (April to November).
At Strafford, median home range and core range estimates of females were
generally smaller and less variable than those of males (Table 1). The home
range estimate (11.6 ha ADK) and core range estimate (4.6 ha ADK) of the
juvenile was intermediate to that of other radio-tagged turtles in Strafford. The
median home range of female turtles in Hillsborough was nearly 5 times larger
436 Northeastern Naturalist Vol. 15, No. 3
than that of female turtles in Strafford. Similarly, median core range size of
females tended to be larger in Hillsborough compared to Strafford. Patterns of
location distribution and concentration also varied between study areas and between
sexes. For example, of 3 turtle core ranges examined in Hillsborough, all
had more than one area of intense use (i.e., bimodal). However, of 8 Blanding’s
Turtle core ranges examined in Strafford, 2 were bimodal and 6 were unimodal;
both males and females exhibited multimodal location distributions.
We compared the average distance traveled per day during each month to
characterize movement patterns. Overall, the average distance traveled per
day for females peaked in June followed by a slow decline in average movement
distance until hibernation (Table 2). Male average movement distance
slowly increased to a peak in August. High average movement distances
for males was maintained into September, but rapidly decreased thereafter.
Average movement distance patterns were similar for females at Strafford
and Hillsborough. Patterns in average movement distance may or may not
be explained by home range size. For example, a male Blanding’s Turtle
at Strafford with consistently large average movement distances (range
= 41.5–44.6 m/d, Jul–Sep) also had the largest home range area (24.8 ha
Table 1. Median (interquartile range) home range (95% of radio locations) and core range (70%
of radio locations) area (ha) estimated by minimum convex polygon (MCP) and adaptive kernel
(ADK) methods for male, female, and juvenile Blanding’s Turtles in southeastern (Strafford)
and central (Hillsborough) New Hampshire during 2000–2002. Combined estimate includes
adult male and female turtles only.
Study area MCP ADK
and turtle class n Home range Core range Home range Core range
Strafford
Female 3 1.5 (0.2–3.0) 0.7 (0.09–1.6) 2.7 (0.4–4.7) 1.0 (0.2–2.7)
Male 4 3.7 (2.0–25.6) 2.8 (1.1–7.1) 8.7 (3.4–22.0) 2.7 (1.3–9.2)
Juvenile 1 3.2 2.0 11.6 4.6
Hillsborough
Female 3 6.8 (3.7–8.7) 2.4 (2.1–3.2) 12.5 (5.0–14.6) 3.1 (2.1–3.2)
Combined 10 3.3 (1.9–7.3) 1.9 (0.9–3.5) 4.9 (3.2–14.0) 2.4 (1.2–3.4)
Table 2. Mean rate of travel (m/day/month), assuming a constant straight-line movement
between successive locations for male (M) and female (F) Blanding’s Turtles in southeastern
(Strafford) and central (Hillsborough) New Hampshire during 2000–2002.
Strafford Hillsborough
F M F
Month m/day SD n m/day SD n m/day SD n
May 22.5 24.1 2 15.3 17.5 2 21.7 3.1 3
June 49.8 35.8 3 28.1 7.3 3 142.9 72.0 3
July 26.4 25.3 3 28.5 15.0 5 74.0 52.8 3
August 21.6 12.8 3 38.3 15.3 4 30.0 11.4 3
September 11.4 6.6 3 32.6 23.3 4 16.3 3.7 3
October 10.3 3.9 3 15.9 12.3 4 8.2 7.0 3
November 4.2 2.1 3 11.3 14.6 4
2008 R.J. Innes, K.J. Babbitt, and J.J. Kanter 437
ADK) throughout the active season in 2001. Conversely, a male turtle with
a relatively small home range area (3.7 ha ADK) had equally large average
movement distances during that time (range: 41.9–58.1 m/d, Jul–Sep).
Radio-tagged turtles were present within overwintering habitat into
April. Turtles began transitioning into surrounding habitats in early May.
From early May to early July, turtles moved frequently among habitat types,
often exhibiting large, dramatic inter-habitat movements and exploratory
forays. Where vernal pools were available, radio-tagged turtles often traveled
from hibernation sites overland to vernal pools upon emergence in the
spring. The movements of one male turtle suggest that he traveled through
the upland during inter-wetland movements on at least 7 occasions in the
spring of 2001 and 2002. Inter-habitat or inter-wetland movements were
generally followed by longer periods of residency before an animal attempted
another inter-habitat or inter-wetland movement, although periods
of residency varied widely and periods of residency were not apparently
correlated with early or late-season activities. Average minimum residency
period within a habitat was approximately 7 weeks (range = 2–20 weeks).
Nesting forays, defined here as movements to and from nesting areas, occurred
between June 6 and July 3 and lasted a minimum of 4 to 16 days (n = 3).
Movement distances from residential wetlands (i.e., wetlands occupied previous
to initiation of nesting activity) to nesting areas ranged from 1.0 to 1.2
km. Vernal pools acted as important staging areas for nesting turtles, as vernal
pools were used during all documented nesting forays in Stafford and Hillsborough.
Nesting areas were generally adjacent to or within 0.2 km of staging
areas. Nesting females always returned to residential wetlands upon completion
of nesting activity. For a nesting female in Hillsborough, the same staging
and nesting areas were used in 2000 and 2001. In addition, in 2000, this female
shared these areas with another nesting female.
Following nesting, activity of female turtles decreased and movements
became less dramatic, as suggested by the decrease in average movement
distance. This shift coincided with a reduction in the amount and variety of
wetland habitat types available due to low water levels. Nonetheless, male
movements continued to increase. Also at this time, estivation and mating
were observed more frequently. We recorded 10 mating observations during
the course of the study; 70% of these occurred during August through October
(Jenkins and Babbitt 2003). Male and female turtles always mated within their
core range. Likewise, radio-tagged turtles always estivated within their core
range. Some radio-tagged turtles did not estivate; however, other individuals
estivated on several occasions. Thirty-nine percent of radio-tagged turtles (4
radio-tagged turtles in Strafford [3 F, 1 M], in addition to the juvenile, and 2 in
Hillsborough [1 F, 1 M]) estivated during July to October. Periods of inactivity
or estivation lasted 5 to 48 days. Although inactivity or estivation occurred in
July and August, it was more likely to occur just prior to overwintering in September
and October. In these cases, estivation was likely to occur within or near
to overwintering habitat. For example, a female in Strafford made infrequent
438 Northeastern Naturalist Vol. 15, No. 3
movements within a 30-m diameter pond on several occasions in September
and in November prior to hibernating there. Turtles mostly estivated in permanent
ponds, except on one occasion when a turtle estivated in upland habitat.
Starting in August, and more frequently in September, turtles began to
transition into overwintering habitat, and movements became exclusive to
one habitat or two adjacent habitats. Turtles ceased movements and entered
hibernation from late October to mid-November. The radio-tagged juvenile
began overwintering earlier (26 October 2001) than the adult radio-tagged
turtles in Strafford (n = 7). Males and females entered dormancy at similar
times. Generally, radio-tagged turtles overwintered within their core range
(84%); however, a male and a female in Strafford overwintered outside
of their core range in 2001 and 2000, respectively, and two females in
Hillsborough overwintered outside of their core range in 2001. Fidelity to
overwintering habitat between years was frequently observed. Thirty-eight
percent of turtles used the same overwintering habitat for 2 consecutive winters.
Fidelity to hibernacula was recorded for one male Blanding’s Turtle in
2000–2001 and 2001–2002. Two female turtles in Hillsborough were found
to enter hibernation on or before 1 November and 11 October, 2000, and
both were found within their hibernacula until 18 April the following spring,
although we did not monitor these turtles throughout the winter.
Discussion
Accurate home range and movement pattern information is critical for determining
Blanding’s Turtle habitat requirements and for guiding land management
and conservation approaches that protect critical resources, such as key
nesting and foraging areas, estivation refugia, and hibernacula. Home range estimates
for Blanding’s Turtles reported in previous studies vary widely (0.56–
63.0 ha MCP; reviewed in Grgurovic and Sievert 2005). Although home ranges
in this study were larger in Hillsborough than in Strafford, home range sizes
in these two areas were more similar to each other than to those recorded from
most other areas of the species’ distribution. Home range sizes recorded in this
study are larger than those recorded in many other populations (Maine [Joyal
1996], Wisconsin [Ross and Anderson 1990], Illinois [Rowe and Moll 1991]),
but smaller than those reported in Massachusetts (Grgurovic and Sievert 2005)
and Minnesota (Hamernick 2000, Piepgras and Lang 2000). Overall, comparison
of home range estimates among studies suggests that New Hampshire
Blanding’s Turtles have intermediate home range sizes.
There are many factors that may contribute to the large variation in home
range estimates among studies. In addition to potential methodological differences,
factors such as age, size, sex, population density, and year-to-year
fluctuations in climatic conditions can influence home range estimations
(Brown and Brooks 1993, Brown et al. 1994, Burke and Gibbons 1995,
Morreale et al. 1984, Schubauer et al. 1990, Stickel 1989, Tuberville et al.
1996). In addition, locality differences related to habitat composition and
availability, and resource distribution, particularly refugia and hibernacula,
2008 R.J. Innes, K.J. Babbitt, and J.J. Kanter 439
also likely affect home range estimates (Carter et al. 1999, Hamernick 2000,
Pettit et al. 1995, Piepgras and Lang 2000). In our study, differences in home
range size between study areas could not be readily explained by differences
in age, body mass, or body size between study areas (Innes et al. 2005).
Further study is needed to elucidate the mechanisms underlying home range
size and movement patterns of this species in New Hampshire.
We found differences between the sexes in activity and movement patterns,
with female activity peaking in June coincident with nesting activity,
and male activity peaking in August and September. Turtles moved less in
October and November as they shifted to overwintering sites. Increased activity
of males in August and September in this study may be explained by an
increase in mating activity observed at this time (Jenkins and Babbitt 2003),
a pattern also observed in Nova Scotia, Canada, populations (Herman et al.
1995). Kofron and Schreiber (1985) found that feeding patterns of Blanding’s
Turtles peaked in June and August, but did not detect a difference in
feeding patterns between males and females. In general, studies concerned
with this species’ movement patterns have found that male Blanding’s
Turtles make more long-distance movements than females in early to late
spring, whereas during the nesting season, females make more long-distance
movements than males (Herman et al. 1995, Ross and Anderson 1990, Rowe
and Moll 1991). Average movement distance was generally not a good
predictor of home range area, with many turtles exhibiting relatively large
average movement distances (>20 m/d) and small home range areas (<5
ha ADK). This result suggests that, for these turtles, movements of greater
distance are of short duration, likely between core areas, with more frequent
smaller movements occurring within core areas.
We found that 45% of Blanding’s Turtle core ranges had bimodal location
distributions. It is not uncommon for Blanding’s Turtles to exhibit disproportionate
use of parts of home range areas during certain times of the year
(Piepgras and Lang 2000, Rowe and Moll 1991). Rowe and Moll (1991) suggest
that location of core range area and duration of core range occupancy may
be indicators of increased habitat quality in these areas; however, support for
this correlation was lacking, and turtles in this study may have been responding
to the other factors. The importance of examining the distribution and placement
of core range areas is further emphasized in our study by the frequent
occurrence of overwintering, mating, and estivation activities within core
ranges. Nonetheless, on several occasions, we found that hibernacula were located
outside of a turtle’s core range. Other studies have found that Blanding’s
Turtles overwinter in summer activity centers (Ross and Anderson 1990), but
many report that Blanding’s Turtles travel great distances to arrive at overwintering
sites (Hall and Cuthbert 2000, Piepgras 1998, Ross and Anderson 1990,
Rowe and Moll 1991). These findings emphasize the importance of including
late season activities in home range and movement estimates in this species.
Overwintering and estivation sites are critical components of Blanding’s
Turtle habitat requirements, as prolonged periods of inactivity may be spent
440 Northeastern Naturalist Vol. 15, No. 3
in a single location. In our study, Blanding’s Turtles reduced activity or estivated
at any one location for periods of 5–48 days, and overwintered in any
one location for as long as 6 months. We found that Blanding’s Turtles shifted
into overwintering habitat beginning in mid-July, with the majority arriving
from mid-August to mid-September, and entered winter dormancy from late
October to mid- to late November. We also found that estivation frequently
graded into hibernation on several occasions, a behavior frequently observed
in turtles (Carr 1952). Other studies found that Blanding’s Turtles arrived at
overwintering areas and entered dormancy at similar times (Hall and Cuthbert
2000, Herman et al. 1995, Rowe and Moll 1991). However, turtles may
be active throughout the winter in some locations (Conant 1938, Kofron and
Schreiber 1985). Herman et al. (1995) found that males generally entered hibernation
later than females. This pattern was not apparent in our study.
Patterns in estivation activity showed greater variation among studies than
overwintering activities. We observed estivation on 9 occasions. Although
unusual, Piepgras and Lang (2000) did not observe any periods of estivation
in 47 radio-tagged turtles throughout the duration of a 16-month study. Ross
and Anderson (1990) and Rowe and Moll (1991) reported terrestrial estivation
on several occasions, with most estivation activity occurring between late
July and August. Mechanisms underlying estivation activity are not generally
understood. Terrestrial estivation has been attributed to cool water temperatures
(Rowe and Moll 1991). Rowe (1987, as referenced in Ross and Anderson
1990) did not find a correlation between aquatic estivation and water temperature.
Future studies should examine specific habitat features associated with
overwintering and estivation activity since availability and location of refugia
and hibernacula also likely affect movement and home range sizes.
In addition to estivation and overwintering sites, particular emphasis
should be placed on the location and habitat features associated with nesting
areas. Blanding’s Turtle nesting behavior and ecology, as well as clutch and
hatchling demography, are well documented. However, location-specific
information regarding nesting activity and key nesting areas is important to
the conservation of the species because nest-site fidelity is common (Congdon
et al 1983; Joyal et al. 2000; Standing et al. 1999, 2000), and nests are
generally found closer to bodies of water other than the maternal female’s
residential wetland (Congdon and Rosen 1983, Piepgras and Lang 2000,
Rowe and Moll 1991). In our study, one female was found to use the same
upland pathway for nesting for 2 consecutive years. In addition, another female
was found to use a similar pathway as this radio-tagged turtle. Nesting
females spent long periods of time outside of home range areas (1–3 weeks)
and used a variety of habitats not available within home range areas (R.J.
Innes and K.J. Babbitt, unpubl. data). For example, all 3 nesting females
in this study were found in small wetlands (i.e., staging areas) near to or
adjacent to nesting areas both prior to and immediately after nesting. Use of
staging areas by females during nesting forays has been reported elsewhere
as well (Congdon et al. 2000). Females in that study always returned to their
2008 R.J. Innes, K.J. Babbitt, and J.J. Kanter 441
areas of residence immediately following a nesting excursion. Joyal et al.
(2000) is the only published account that found a female Blanding’s Turtle
who did not return to her residential wetland after nesting.
Knowledge of all aspects of reproduction and life history will be critical
in determining the best conservation and monitoring strategies for this species
(Dodd 1997, Pedrono et al. 2001, Tinkle et al. 1981). Information on
a larger sample of Blanding’s Turtles, especially nesting females, would be
beneficial for conservation efforts aimed at all aspects of Blanding’s Turtle
ecology. Identifying important movement corridors, for example, where
more than one turtle share the same pathway for nesting year after year, may
be important when considering conservation approaches in areas subject to
fragmentation. In addition, identifying wetland habitats that are important
overwintering and estivating areas is an important component of effective
habitat management for the Blanding’s Turtle.
Acknowledgments
We thank E. Snyder of UNH, Cooperative Extension for her continued, enthusiastic
support. We thank D. Carroll for providing data and sharing his expertise and
vast knowledge of Blanding’s Turtles in New Hampshire. We recognize the New
Hampshire GRANIT database for providing the data layers used in the analyses.
The following people made notable contributions to this study by assisting with data
collection and turtle captures: M. Baber, A. Beaulieu, S. Callaghan, D. DeGraaf,
M. Hinderliter, M. Libby, A. Shutt, E. Snyder and T. Tarr of the University of New
Hampshire; C. Andrews, A. Briggaman, A. Curtis, C. Goulet, D. Hayward, M. Medeiros,
J. Philippy, and N. Schroeder of New Hampshire Fish and Game Department;
and L. Demming of the Audubon Society of New Hampshire. In addition, we thank
D. Sewall and family, and all others who have provided information on local nesting
areas and access to their properties. This work was supported by the New Hampshire
Fish and Game Department and the New Hampshire Department of Environmental
Services with funds from the US Environmental Protection Agency. This work was
conducted with the approval of the University of New Hampshire IACUC (protocol
#000307) and under appropriate state permits. This paper is Scientific Contribution
Number 2299 from the New Hampshire Agricultural Experiment Station.
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