Satellite Telemetry and Long-Range Bat Movements
Citation: Smith CS, Epstein JH, Breed AC, Plowright RK, Olival KJ, et al. (
Satellite Telemetry and Long-Range Bat Movements
Craig S. Smith 0
Jonathan H. Epstein 0
Andrew C. Breed 0
Raina K. Plowright 0
Kevin J. Olival 0
Carol de Jong 0
Peter Daszak 0
Hume E. Field 0
Justin Brown, University of Georgia, United States of America
0 1 Biosecurity Sciences Laboratory, Department of Employment, Biosecurity Queensland, Economic Development & Innovation , Coopers Plains, Queensland , Australia , 2 EcoHealth Alliance, New York City , New York, United States of America, 3 Centre for Epidemiology and Risk Analysis, Veterinary Laboratories Agency , Addlestone, Surrey , United Kingdom , 4 Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California Davis , Davis, California , United States of America
Background: Understanding the long-distance movement of bats has direct relevance to studies of population dynamics, ecology, disease emergence, and conservation. Methodology/Principal Findings: We developed and trialed several collar and platform terminal transmitter (PTT) combinations on both free-living and captive fruit bats (Family Pteropodidae: Genus Pteropus). We examined transmitter weight, size, profile and comfort as key determinants of maximized transmitter activity. We then tested the importance of bat-related variables (species size/weight, roosting habitat and behavior) and environmental variables (day-length, rainfall pattern) in determining optimal collar/PTT configuration. We compared battery- and solar-powered PTT performance in various field situations, and found the latter more successful in maintaining voltage on species that roosted higher in the tree canopy, and at lower density, than those that roost more densely and lower in trees. Finally, we trialed transmitter accuracy, and found that actual distance errors and Argos location class error estimates were in broad agreement. Conclusions/Significance: We conclude that no single collar or transmitter design is optimal for all bat species, and that species size/weight, species ecology and study objectives are key design considerations. Our study provides a strategy for collar and platform choice that will be applicable to a larger number of bat species as transmitter size and weight continue to decrease in the future.
Funding: This study was core-funded by an NSF/NIH Ecology of Infectious Diseases award (R01 TW005869) from the John E. Fogarty International Center (http://
www.fic.nih.gov/) awarded to Peter Daszak, and partially funded by the Australian Biosecurity Cooperative Research Centre for Emerging Infectious Diseases
(http://www.abcrc.org.au/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
Old-World fruit bats (Family Pteropodidae) play a vital ecological
role as pollinators and seed dispersers in forest ecosystems .
Many species are nomadic, shifting roosting and foraging locations
in accordance with food availability [2,3,4]. The pattern and
magnitude of these nomadic movements are, for the most part,
poorly understood , but individual movements of over 1,500
kilometers have been reported .
Population declines and altered population dynamics have been
reported in many fruit bat species, and are likely a response to
deforestation and other anthropogenic habitat changes . In
some cases, these changes increase the likelihood of contact
between fruit bats, domestic animals and humans [8,9] and are
hypothesized to have promoted the emergence of several highly
pathogenic zoonotic agents from fruit bats, including Nipah virus
in Asia [10,11,12,13] and Hendra virus in Australia [14,15,16].
Understanding the movement dynamics of fruit bats informs both
their conservation management and the mitigation of disease
Satellite telemetry has been used to elaborate the frequency and
magnitude of fruit bat movements [17,18,19]. However, the
effective deployment of satellite transmitters on bats poses unique
challenges because of their size (typically ,1 kg), anatomy (wing
membrane stretching from forelimb to hindlimb), roosting
behavior (inverted and colonial), and life history traits (mothers
carry pups in flight). Further, the weight and dimensions of
available platform terminal transmitters (PTTs), notwithstanding
recent advances, make ready and effective attachment to bats
difficult. These issues threaten both the quality and duration of
transmissions, and potentially the health and welfare of tagged
In this paper we provide the most comprehensive overview of
satellite telemetry methods in bats to date, and describe our
development and trialing of collar and PTT configurations on
both free-living and captive fruit bats (genus Pteropus, family
Pteropodidae), commonly known as flying foxes. We discuss the
strengths and weaknesses of each configuration to identify key
design determinants affecting satellite telemetry study outcomes,
based on successful field trials in Southeast Asia and Australasia.
Study 1: Collar design
We sequentially developed three collar designs using results
from field and captive trials to inform subsequent modifications,
and incorporating Microwave TelemetryTM PTTs. Design 1
(Fig. 1a) was a modification of a collar and bib design described by
Tidemann and Nelson  to accommodate the elongated shape
of the 18 g solar-powered PTT (62 mm 618 mm 612.5 mm) and
the 20 g battery-powered PTT (54 mm618 mm 617 mm) . It
positioned the PTT along the dorsal aspect of the neck, between
the scapulae and parallel to the axis of the spine. The one-piece
collar and bib was made from 1.4 mm veggie-tan leather; the
collar was 11 mm wide and the bib was 28 mm wide and long
enough to accommodate the PTT. (Veggie-tan refers to leather
treated with tannins of plant origin, and chrome (below) to
leather treated with chromium sulfate; the latter generally
produces softer and more flexible leather). The PTT was attached
to the bib with an all-weather contact adhesive (Selleys, Australia)
and nylon thread (using the PTT attachment loops). The thread
and knots were sealed using a two-part epoxy resin . This
design was used with three 18 g solar-powered PTTs and four
20 g battery-powered PTTs (Table 1).
Design 2 (Fig. 1b) used a softer chrome leather collar, and was
initially designed to accommodate a 12 g solar-powered PTT
(43 mm 618 mm 614 mm) modified by the manufacturer at our
request; the antenna was rotated 90u to be perpendicular to the
length of the PTT. The collar design positioned the PTT
transversely on the dorsal aspect of the neck, perpendicular to
the spine. The collar was 1.4 mm thick and 11 mm wide, with a
wider section to accommodate the PTT. The PTT was first
mounted on a curved bracket of 1 mm thick aluminum (39 mm
612 mm; curve diameter 32 mm) using a two-part epoxy resin.
The bracket was then glued and stitched to the collar as described
previously. Sheepskin, with the wool trimmed to 3 mm, was glued
to the inside surface of the collar with all-weather contact adhesive.
This design was used with six 12 g solar powered PTTs and later,
with four (similarly modified) 20 g battery-powered PTTs
Design 3 (Fig. 1c) used a modified proprietary leather cat collar
to accommodate a 22 g battery-powered PTT (42 mm 618 mm
614 mm) with aerial alignment modified as above. This design
positioned the PTT transversely on the dorsal aspect of the neck,
perpendicular to the spine, but (because of its compact dimensions)
without the need for the bracket used in design 2. The PTT was
attached to the 11 mm wide collar using 30 mm heat-shrink
tubing, and further secured with nylon thread again embedded in
a two-part epoxy resin. The inside of the collar was lined with
neoprene that extended 3 mm either side, and was glued and
stitched to the collar as described previously. This design was used
to deploy two 22 g battery-powered, implantable PTTs (Table 1).
All bats were anesthetized prior to collar attachment for animal
welfare reasons (to avoid extended physical restraint) and to
ensure collar fit was optimized. In Australia, (Bats AC and K
N), the inhalation agent IsofluraneTM was used as described by
Jonsson . In Malaysia (Bats DJ), Timor Leste (Bats O and P)
and Papua New Guinea (Bats QT), flying foxes were
anesthetized using a combination of ketamine hydrochlorine
and xylazine injected into the pectoral muscles . Collars were
secured with two brass rivets, leaving a 78 mm gap between
collar and neck to facilitate normal respiration, feeding and
grooming, while endeavoring to ensure that the collar could not
slip over the head. Bats were released at their point of capture
within 30 minutes of recovery from anesthesia, and within 2 hrs
Study 2: Solar-powered PTT assessment
Half of the 20 PTTs deployed were solar-powered (Table 1).
Transmission and battery characteristics of these PTTs were
compared to those of the 10 battery-powered PTTs. Prior to
deployment, we assessed battery-charging efficiency under
different light conditions on two 12 g solar-powered PTTs mounted on
top of a 4 m wooden mast erected in an open area (in Brisbane,
Australia) during August and September 2005. The solar panels of
one had a southern aspect and thus were not exposed to direct
sunlight; the solar panels of the other faced north, and were
exposed to direct sunlight. The intended deployment duty cycle of
7 hrs ON and 155 hrs OFF was used, and voltage recorded at the
beginning of each duty cycle over a 4-week period. Voltage was
recorded from the first signal received which contained sensor
data, and within the first 2 hrs of the ON duty cycle.
Subsequently, after fully recharging by exposure to a 100 Watt
incandescent light bulb at a distance of 15 cm for 12 hours, these
PTTs were deployed on two male P. scapulatus (Bats K and L) in
October 2005. Data were collected from two other 12 g
solarFigure 1. Examples of the three collar designs. A) Collar design 1, an 18 g solar powered PTT deployed on a black flying fox (Pteropus alecto)
along the dorsal aspect of the neck, between the scapulae and parallel to the axis of the spine. B) Collar design 2, a 12 g solar powered PTT deployed
on a little red flying fox (Pteropus scapulatus) on the dorsal aspect of the neck and perpendicular to the axis of the spine. C) Collar design 3, a 22 g
battery powered PTT deployed on a Bismarck or great flying fox (Pteropus neohibernicus) on the dorsal aspect of the neck and perpendicular to the
axis of the spine.
Duty Cycle (ON/OFF h)
powered PTTs deployed on additional species to assess whether
roosting density and roosting height influenced solar-powered
PTT performance. One was deployed on Bat H, a male
P. vampyrus in southern Peninsular Malaysia; the other on Bat Q,
a male P. alecto from southern Papua New Guinea.
Study 3: Location Class Error
PTTs transmit signals to Argos receivers on National Oceanic
and Atmospheric Administration polar-orbiting environmental
satellites which provide full global coverage . These satellites,
orbiting at an altitude of 850 km, re-transmit the signals to Argos
centers (in France, USA, Australia, Japan and Peru) where they
are processed and the location of the PTT is calculated. The
locations are assigned an error or LC, defined by Argos as 3
(,150 m), 2 (150,300 m), 1 (300,1000 m), 0 (.1000 m), and A,
B and Z (no error range calculable). Locations are typically
calculated by the Argos processing centers after receiving a
minimum of 4 signals from a PTT, with an interval of at least 240
seconds . An important source of error originates from the
stability of the PTT oscillator, which is largely influenced by
temperature. Argos certification requires a stability of 4 Hz over
20 min, which would result in 65% of errors being ,1100 m .
The accuracy of the Argos location class (LC) error was assessed
by comparing the difference between 49 Argos reported locations
from 6 PTTs over 4 duty cycles with their actual (known) location
(atop the 4 m wooden mast described in Study 2), determined
using an eMap GPS . Location data were plotted using
Arcview 3.3  using Argos Tools  and the actual error
Study 4: Captive bat studies
Two separate trials on captive bats were undertaken to assess
any effect of collaring on bat behavior and health. In the first trial,
prior to deployment of the first PTT, five wild-caught P. alecto
(recruited for an unrelated study) were fitted with Design 2 collars
mounted with mock 12 g solar powered PTT, and monitored for
up to 28 days. Bats 1, 3 and 4 had collars made from chrome
leather, lined with sheepskin trimmed to 10 mm. Bat 29s collar was
unlined chrome leather, and Bat 59s collar was unlined
veggietan leather. The bats were observed daily, and the skin
underneath and around the collar was closely examined under
inhalation anesthesia (as described above) on days 15, 7, 9, 14, 21
and 28. On Day 9, all collars were rotated 180u so that the PTT
was on the ventral surface of the neck, to establish if bats could
dorsally re-position the PTT. The bats were observed after
recovery and on subsequent days.
In the second trial, ten rescued and recuperating wild flying
foxes (8 P. scapulatus and 2 P. conspicillatus) were housed
communally in a large flight enclosure at a wildlife rehabilitation
facility. These bats were fitted with a real or dummy transmitter on
a Design 2 collar and observed for up to 28 weeks.
Location data was received from the Argos processing center
using Telnet Client and Telnet Inferno  or received by email
from the Argos Automatic Distribution Service. In Studies 1 and
2, range and median values of transmitter activity were calculated.
In Study 2, a two-sample t-test was used to compare battery
voltage under different light intensities. In Study 3, the mean error
and standard variation between known actual PTT locations and
Argos reported locations were calculated. Statistical analysis was
performed using the Data Analysis package in Microsoft Office
EXCEL 2003  or GenStat 9th Version .
Permits and Animal Welfare
All studies performed on live animals followed American
Society of Mammalogists guidelines  and were approved by
the Queensland Department of Industries and Fisheries and The
University of Queensland animal ethics committees, the
Queensland Parks and Wildlife Service, and respective wildlife agencies in
Malaysia, Papua New Guinea and Timor-Leste.
Study 1: Collar Design
Observations prior to release showed all three collar designs to
be well-tolerated by bats; no scratching, biting or panic behavior
was observed in any bat. All collar designs maintained the PTT in
the desired dorsal position. With Design 1, there was a tendency
for the bib to hinge outwards from the collar under the weight of
the PPT when the bat was roosting (upside-down). With Design 2,
the mounting bracket allowed the collar to conform well to the
curvature of the neck of the bat, but moved the centre of gravity of
the PTT 1012 mm out from the neck, leading to a tendency (at
roost) for the collar to flex in the transverse plane with the weight
of the PTT. This tendency was not evident with Design 3.
The range of transmitter activity on Designs 1, 2, and 3 was 2
231 days (median 121 days), 27341 days (median 47), and 62
108 days (median 85) respectively (Table 1). The range of
transmitter activity on 12 g solar, 18 g solar, 20 g battery, and
22 g battery PTTs was 27341 days (median 47), 121231 days
(median 225), 2146 days (median 104), and 62108 days (median
85) respectively (Table 1). The range of transmitter activity on P.
alecto, P. scapulatus, P. neohibernicus, and P. vampyrus was 47341 days
(median 225), 2768 days (median 34), 62108 days (median 85),
and 2146 days (median 103) respectively (Table 1).
Study 2: Solar-powered PTT assessment
The range of transmitter activity on the deployed solar- and
battery-powered PTTs was 27341 days (median 63) and 2146
days (median 104), respectively. In the pre-deployment assessment,
there was a statistically significant difference between the mean
weekly battery voltage of the PTT exposed to direct sunlight and
the PTT not exposed to direct sunlight (t = 232.08, df = 6,
P = ,0.001). The former had a mean of 4.2 volts (SD = 0.012); the
latter had a mean of 3.96 volts (SD = 0.01). Mean day-length over
the 4-week period was 11 hrs 40 mins.
After deployment, Bats K and L transmitted for 4 and 8 weeks
respectively until battery voltage was 3.76 and 3.78 respectively
(Fig. 2). Mean day-length in northern Australia over the trial
period was 12 hrs 35 mins. Bat H transmitted for 8 weeks, with a
mean weekly battery voltage of 3.83 (SD = 0.05). Mean day-length
in Peninsular Malaysia over the trial period was 12 hrs 10 mins.
Bat H was killed by a hunter (and the PTT returned to the
authors) (Fig. 2). Bat Qs PTT maintained a mean weekly voltage
of 4.07 V (SD = 0.08, n = 39) during its 48 weeks of deployment
(Fig. 2). Mean day-length in Papua New Guinea over the trial
period was 12 hours 5 mins. The mean voltage of PTT Q was
significantly higher (F = 21.3, df = 47, P = ,0.001) in (southern
hemisphere) spring (September to November 2006, x = 4.16 V,
SD = 0.04, n = 13) than autumn (March to May 2007, x = 3.96 V,
SD = 0.04, n = 14) but not summer (December 2006 to February
2007, x = 4.04 V, SD = 0.07, n = 13) or winter (June to August
2006, x = 4.02 V, SD = 0.11, n = 8), (Fig. 2).
Study 3: Location Class Error
The mean error between Argos reported locations and actual
PTT locations was 199 m (SD = 128, n = 43) for LC error 3,
306 m (SD = 165, n = 17) for LC error 2, 1403 m (SD = 2346,
n = 7) for LC error 1, and 3679 m (SD = 1523, n = 2) for LC error
Study 4: Captive bat studies
In the first trial, none of the five P. alecto showed any serious
adverse effect of collaring. All were observed to eat, groom, move,
and otherwise behave normally. Bats 13 showed mild reddening
of the skin underneath the collar until day 9, but not subsequently.
Bat 4 lost one rivet from its collar on day 7. Bat 5 developed a
7 mm diameter callus either side of the trachea from day 9. All
bats had re-orientated their 180u rotated collars on day 10.
In the second trial, of the 8 P. scapulatus and 2 P. conspicillatus,
one P. conspicillatus continually licked at the collar and his neck in
the 48 hrs post-collaring. The collar was removed and the bat took
no further part in the trial. All nine other bats appeared to tolerate
the collars well, and at six weeks post-collaring, no negative
impacts were evident. This period coincided with the breeding
season of P. scapulatus, and mating was observed to occur normally
and unencumbered for both collared males and females. At 8
weeks post-collaring, two P. scapulatus were found to have
moderate moist dermatitis and ulceration on the ventro-lateral
aspect of the neck. Both collars were removed and both bats
recovered fully with treatment. At 14 weeks, the collar of the
remaining P. conspicillatus was removed prior to its release to the
wild. Mild hair loss was evident. At 15 weeks, two collars (without
bats) were found caught on a metal hook which suspended feeding
stations from the roof of the enclosure. The respective bats were
unharmed and no collar-related lesions were evident. At 18 weeks,
three of the remaining four bats had mild hair loss under the
collar, and the fourth had severe hair loss and minor skin abrasion;
the collar was removed from the latter. At the end of the trial,
28weeks post collaring, the collars were removed from the remaining
three bats: two had the mild hair loss previously evident; the third
had a severe and extensive suppurative dermatitis on the
ventrolateral aspects of the neck, and had lost 25% of bodyweight. It
recovered fully with treatment.
Study 1: Collar Design
This study incorporates the largest sample size (n = 20) of
satellite transmitters deployed on bats to date. However, due to the
high cost of PTTs, (,$3000 USD), the number of replicates was
limited, which reduced our ability to control variables such as PPT
type and species.
Premature cessation of transmission (defined by us as ,100
days) occurred with 10/20 (50%) deployments, and with all collar
designs, with both battery and solar PTTs, and with all species
(albeit that limited replicates preclude statistical analysis). This
outcome is a major constraint to data collection and warrants
discussion. Premature cessation of transmission could be due to a
number of factors. The possibility that 50% of transmitters could
be technically faulty is both disconcerting and improbable,
although it is tempting to attribute the simultaneous failure of
PTTs O and P (with identical deployment histories) at 47 days to
battery/charge issues. Transmitter loss is another possible factor,
however it is again improbable that 50% of collars would either
lose their PTT or be lost from the bats with PTT attached. The
captive bat trials suggest that collars can be associated with
negative health impacts and loss of body condition (albeit in a
minority of individuals), so premature bat mortality cannot be
discounted as a possible explanation for early cessation of
transmissions. Such premature mortality might plausibly result
from secondary infection of lesions such as those seen in our
captive trials, or from increased vulnerability to hunting. Note that
Bat H was trapped and killed by a hunter in Peninsular Malaysia
42 days after release. Regardless of the cause, premature cessation
of transmission is a key challenge to telemetry . The PTTs we
used were equipped with an activity sensor, however the sensor
does not distinguish between a flying fox that has died, a collar that
has fallen off, or a PTT that has developed a technical fault. Some
of our PTTs were equipped with a ground-track capability,
wherein the PTT emits a VHF signal upon mortality,
theoretically allowing the use of a handheld antenna and receiver
to retrieve the PTT. However, in many cases, retrieval is likely to
be impractical due to remoteness or inaccessibility.
A fundamental tenet of telemetry studies is that instrumentation
should not interfere with normal behavior; the consequence of
such interference is potentially more significant in volant species
than in terrestrial species . It is our contention that flying foxes
across their range are under increasing ecological pressure, and
that energetic margins are slim. Indeed we sought to deploy
transmitters only on mature male bats (although bat S was a
mature female), mindful of the additional seasonal burden that
breeding females are subject to in carrying young pups. Thus, the
collar and bib design (Design 1), accommodating large PTTs,
cannot be recommended. In Designs 2 and 3, modification of
PTTs to ensure that the antenna lay parallel to the axis of the
spine allowed us to achieve the optimum plane for signal
transmission by allowing the animals body to act as a ground.
However in Design 2, the sheepskin lining became matted over
time when contaminated with secretions or wastes, reducing its
effectiveness to offer protection from the leather, and potentially
providing a nidus for bacterial or fungal skin infection. Also, the
curved aluminum mounting bracket used in Design 2 could
increase the likelihood of animals becoming snagged and suffering
injury and/or collar loss. Filling the gap between the top and
bottom faces of the bracket would remove the increased risk, but
would also add to overall weight. In our experience, the need for a
bracket is dependent on two factors: the circumference of the bats
neck, and the length of the (horizontally aligned) PTT. If affixing
the PTT directly to the collar deforms the circular shape of the
collar relative to the bats neck, a bracket should be considered.
We suggest that this is likely when the length of the PTT
approached the diameter of the bats neck. Our observations
suggest that the tendency for collar flexing when a bracket is
incorporated in the design is independent of PTT model, and is
fundamentally due to the centre of gravity of the transmitter being
placed out from the bats neck, albeit that a PTT with a high (vs
low) profile would exacerbate this. A wider collar may reduce this
flex, but may also increase the likelihood of rub-induced trauma to
the angle of the jaw and the neck, and is not recommended.
In Design 3, the compact implantable PTT attached directly to
the collar makes the bracket redundant, and the non-absorbent
neoprene lining protects from abrasion and infection. We believe
this design best addresses the key issues of weight, size, profile and
In this study, we anaesthetized all bats prior to fitting collars,
based on our previous experience in handling Pteropus species. The
reasons are three-fold: firstly, to ensure an optimal collar fit - under
anaesthetic, the animal is in a relaxed state and the natural
proportions of the neck can be ascertained; secondly, from a
workplace safety perspective anaesthesia removes the risk of bite
incidents while working close to the mouth; thirdly, from an
animal welfare perspective - fitting the collar correctly takes time
and manipulation of the head and neck of the bat, and anaesthesia
avoids any associated stress.
We have not investigated built-in collar release/failure
mechanisms in this study. There are sound welfare and ethical bases for
this consideration, but significant practical challenges exist with
some species in achieving a tightly pre-determined time of release.
We secured collars with two rivets in an endeavor to ensure that
premature collar loss did not occur, and relied on the weathering
and deterioration of the collar leather to facilitate eventual collar
failure and collar/transmitter shedding. The leather collars we
used were typically 11 mm wide and 1.4 mm thick; with two hole
punches of 34 mm approximately 15 mm apart to accommodate
the rivets, the remaining 34 mm of leather on either side of the
hole being the likely point of failure over a one-two year
timeframe, or if a bat were caught in vegetation by the collar.
Interestingly, our captive trials demonstrated both premature rivet
loss (in one of five bats after 7 days, the rivet having been
incorrectly fastened) and the ability for bats to slip out of the collar
when it was caught on a snag (two of ten bats, seven weeks
postcollaring). However, individual leather and environmental
variables make precise quantification of collar failure unfeasible.
Study 2: Solar-powered PTT assessment
Our original aim was to obtain a multi-year transmission
period to examine long-term movement of flying foxes. Our
initial battery-powered PTTs offered a maximum one-year
operational life even with modest duty cycles. Solar powered
PTTs (35 g) have been used successfully to collect data on bird
movement for 3 years . Our pre-deployment trial indicated
that the 12 g solar powered PTTs had the ability to charge the
battery when exposed to both direct and indirect sunlight. This is
a fundamental issue given that flying foxes spend the daylight
hours hanging in an inverted vertical position in trees, and
indicated that solar-powered PTTs could theoretically be used in
flying foxes. However, in practice, the efficiency of the solar panel
charging, and transmitter activity varied among species. Solar
powered PTTs were deployed on three species (P. alecto,
P. vampyrus and P. scapulatus), but only those on P. alecto were
able to maintain a voltage sufficient for operation. This species
typically roosts on the upper and outer branches, and at low to
moderate colony densities, where the solar panels are plausibly
exposed to extended periods of direct and indirect sunlight; in
contrast, P. scapulatus tend to roost low to the ground, beneath
dense foliage, and in large and dense colonies, such that panels
are likely exposed to infrequent and indirect sunlight. Thus, when
P. scapulatus is included in our analysis, the median period of
transmitter activity for solar-powered PTTs is 68 days; when P.
scapulatus is excluded, the median period is 225 days. As
previously noted, a hunter killed the single P. vampyrus fitted with
a solar powered PTT 42 days after deployment.
The counterintuitive finding of PTT Q having a higher mean
voltage in spring than summer, despite an hour less sunlight, could
plausibly be explained by the heavy and frequent monsoonal rains
on the southern coast of New Guinea during this period. This
would reduce both direct and indirect sunlight, and also drive
flying foxes to seek shelter in denser vegetation. Thus, in addition
to roosting habitat and behavior, the nature and pattern of
prevailing weather should also be considered before employing
Study 3: Location Class Error Trial
We found the range of actual errors to be similar to, but slightly
higher than, the LC errors stated by Argos. These findings
corroborate those of White & Sjoberg , who, using satellite
relay dataloggers and differentially corrected GPS units, also found
the accuracy of location class estimates to be similar to those
reported by Argos.
Study 4: Captive bat studies
Our first trial aimed to identify any adverse impacts of
collaring, using Design 2 collars mounted with mock 12 g solar
powered PTTs. The transient reddening of the skin under the
collars on Bats 13 (lined and unlined chrome leather) is likely
due to minor irritation prior to bats becoming accustomed to
their new collars. The callused skin over the throat of Bat 5
suggests more chronic irritation, likely due to the less pliable
nature of the veggie-tan leather collar, which should thus be
considered unsuitable for collars. In our second, long-term
captive trial, we found that the sheepskin lining used in these
bats collars became matted, lost resilience over time and caused
moderate to severe ventral and lateral neck ulceration in 3/10
bats. These lesions were evidently sufficient to affect behavior and
are a clear ethical and animal welfare concern. That all three bats
affected were P. scapulatus suggests a species-level effect. A
plausible explanation is that the smaller size of P. scapulatus
means that a collar width appropriate for a larger (and longer
necked) species might cause constant abrasion to the angle of the
jaw of a smaller (and shorter necked) species. The involvement of
the angle of the jaw evident in Fig. 1b supports this explanation.
Thus collar width may be another important consideration in
The observation on Day 10 of the first captive trial (after the
intentional rotation of the mock PTTs on Day 9) that all five flying
foxes had re-orientated the PTT to the dorsal aspect, established
that flying foxes were able to reposition the PTT, presumably for
comfort. Fortunately, this apparent bat-preferred orientation is
also optimal for transmission and for maximizing solar panels
exposure to sunlight. Observations in the second trial support
those of the first: all bats had dorsal alignment of the PTT
throughout the 28 week trial.
Satellite telemetry is undoubtedly a valuable tool for studying
the long-distance movement of bats. However, it is evident that
both data validity and maximum transmission period are
dependent on optimal PTT/collar configuration. Our study
suggests that no one design configuration suits all scenarios, and
that (in addition to the study objectives) both biological variables
(species size/weight, roosting habitat and behavior) and climatic
variables (day-length, rainfall pattern) are key considerations in
transmitter and collar configuration. However, a number of
specific insights on optimizing PTT/collar configuration flow from
our work: a neoprene collar, a compact PTT mounted directly to
the collar, and an aerial orientation perpendicular to the PTT
along the dorsum. In addition, we support the recommendations
of others that the combined collar/PTT weight not exceed 5% of
bat body weight. This is most practically achieved by restricting
collaring to adult male bats.
For battery-powered PTTs, it is evident that, for any given bat
size/weight and PTT dimension/weight, compromise is required
between frequency/duration of transmission and the length of the
study. Future reduction of PTT size and weight (largely
batterydependent) may alleviate these and other design issues.
Finally, it is evident that there is considerable variability among
species, and that the potential exists for significant ethical and
animal welfare issues.
We thank Jenny Maclean and the Tolga Bat Hospital for hosting and
monitoring the second captive trial, Patrina Birt, Nikki Markus, John
Nelson, and Louise Shilton for their bat biology perspective, Guan Ong for
assistance with the Argos program, and John Burke, Les Hall, Tom
Hughes, Tim Kerlin, Carol Palmer, Sohayati Abdul Rhaman, Craig
Walker, the Australian Quarantine and Inspection Service, Queensland
Parks and Wildlife Service, and the Northern Territory Parks and Wildlife
Commission for facilitating the deployment of PTTs.
Conceived and designed the experiments: CSS JHE ACB RKP KJO PD
HEF. Performed the experiments: CSS JHE ACB RKP. Analyzed the
data: CSS KJO HEF. Contributed reagents/materials/analysis tools: CSS
KJO PD. Wrote the paper: CSS JHE ACB RKP KJO CdJ PD HEF.
1. Fujita MS , Tuttle MD ( 1991 ) Flying foxes (Chiroptera: Pteropodidae): Threatened animals of key ecological and economic importance . Conservation Biology 5 : 455 - 463 .
2. Eby P ( 1991 ) Seasonal movements of Grey-headed flying-foxes, Pteropus poliocephalus (Chiroptera: Pteropodidae), from two maternity camps in northern New South Wales . Wildlife Research 18 : 547 - 559 .
3. Parry-Jones K , Augee M ( 2001 ) Factors affecting the occupation of a colony site in Sydney, New South Wales by the Grey-headed Flying-fox Pteropus poliocephalus (Pteropodidae) . Austral Ecol 26 : 47 - 55 .
4. Vardon MJ , Brocklehurst PS , Woinarski JCZ , Cunningham RB , Donnelly CF , et al. ( 2001 ) Seasonal habitat use by flying-foxes, Pteropus alecto and Pscapulatus (Megachiroptera), in monsoonal Australia . Journal of Zoology 253 : 523 - 535 .
5. Hall L , Richards G ( 2000 ) Flying foxes: Fruit and Blossom Bats of Australia; Dawson TJ, editor. Sydney: University of New South Wales Press Ltd.
6. Breed AC , Field HE , Smith CS , Edmonston J , Meers J ( 2010 ) Bats without borders: long distance movements of flying-foxes and implications for disease risk management . EcoHealth: In Press.
7. Mickleburg S , Hutson A , Racey P ( 1992 ) Old World fruit bats: an action plan for their conservation . Gland, Switzerland: IUCN.
8. Markus N , Hall L ( 2004 ) Foraging behaviour of the black flying-fox (Pteropus alecto) in the urban landscape of Brisbane , Queensland. Wildlife Research 31 : 345 - 355 .
9. Williams NSG , McDonnell MJ , Phelan GK , Keim LD , Van der Ree R ( 2006 ) Range expansion due to urbanization: Increased food resources attract Greyheaded Flying-foxes (Pteropus poliocephalus) to Melbourne . Austral Ecology 31 : 190 - 198 .
10. Chua K , Bellini W , Rota P , Harcourt B , Tamin A , et al. ( 2000 ) Nipah virus: A recently emergent deadly paramyxovirus . Science 288 : 1432 - 1435 .
11. Chua K , Koh C , Hooi P , Wee K , Khong J , et al. ( 2002 ) Isolation of Nipah virus from Malaysian Island flying foxes . Microbes Infect 4 : 145 - 151 .
12. Daszak P , Plowright R , Epstein JH , Pulliam J , Abdul Rahman S , et al. ( 2006 ) The emergence of Nipah and Hendra virus: pathogen dynamics across a wildlife-livestock-human continuum . In: Collinge S, Ray C, eds. Disease Ecology: Community structure and pathogen dynamics : Oxford University Press.
13. Hsu V , Hossain M , Parashar U , Ali M , Ksiazek T , et al. ( 2004 ) Nipah Virus Encephalitis Reemergence , Bangladesh. Emerging Infectious Diseases 10 : 2082 - 2087 .
14. Field H , Young P , Yob JM , Mills J , Hall L , et al. ( 2001 ) The natural history of Hendra and Nipah viruses . Microbes and Infection 3 : 315 - 322 .
15. Mackenzie J , Field H , Guyatt K ( 2003 ) Managing emerging diseases borne by fruit bats (flying foxes) with particular reference to Henipaviruses and Australian bat lyssavirus . Journal of Applied Microbiology 94.
16. Selvey L , Wells RM , McCormack JG , Ansford AJ , Murray PK , et al. ( 1995 ) Infection of humans and horses by a newly described morbillivirus . Med J Aust 162 : 642 - 645 .
17. Tidemann C , Nelson J ( 2004 ) Long-distance movements of the grey-headed flying fox (Pteropus poliocephalus) . Journal of Zoology 263 : 141 - 146 .
18. Richter HV , Cumming GS ( 2008 ) First application of satellite telemetry to track African straw-coloured fruit bat migration . Journal of Zoology 275 : 172 - 176 .
19. Epstein JH , Olival KJ , Pulliam J , Smith C , Westrum J , et al. ( 2009 ) Pteropus vampyrus, a hunted migratory species with a multinational home-range and a need for regional management . Journal of Applied Ecology 46 : 991 - 1002 .
20. Anon ( 2010 ) Microwave Telemetry Inc . http://microwavetelemetrycom/.
21. Anon ( 2010 ) Selleys Australia . http://wwwselleyscomau/Selleys-Araldite-UltraClear/defaultaspx.
22. Jonsson NN , Johnston SD , Field H, de Jong C , Smith C ( 2004 ) Field anaesthesia of three Australian species of flying fox . Veterinary Record 154 : 664 .
23. Heard DJ , Beale C , Owens J ( 1996 ) Ketamine and ketamine:xylazine ED50 for short-term immobilization of the island flying fox (Pteropus hypomelanus) . Journal Of Zoo And Wildlife Medicine 27 : 44 - 48 .
24. Anon ( 2010 ) CSL (Collecte Localisation Satellites ) http://wwwclsfr/ welcome_enhtml.
25. USGS ( 1998 ) Operation Crane Watch . ,http://wwwnpwrcusgsgov/resource/ birds/cranemov/indexhtm. (Version 11JUN2004 ). Jamestown, ND: Northern Prairie Wildlife Research Center Online.
26. Anon ( 2010 ) Garmin International . http://wwwgarmincom/garmin/cms/site/ us.
27. Anon ( 2010 ) Environmental Systems Research Institute Inc . http:// wwwesricom/.
28. Anon ( 2010 ) Argos - Tools Support site . http://gis-labinfo/programs/argos/.
29. Anon ( 2010 ) The TELNET protocol . http://supportmicrosoftcom/kb/231866.
30. Anon ( 2010 ) Microsoft, USA. http://wwwmicrosoftcom/en/us/defaultaspx.
31. Anon ( 2010 ) VSN International Ltd . http://wwwvsnicouk/.
32. Gannon WL , Sikes RS ( 2007 ) Guidelines of the American Society of Mammalogists for the Use of Wild Mammals in Research . Journal of Mammalogy 88 : 809 - 823 .
33. Bander R , Cochran W ( 1991 ) Radio-location telemetry . Washington D.C.: Wildlife Society.
34. Olival KJ , Higuchi H ( 2006 ) Monitoring the long-distance movement of wildlife in Asia using satellite telemetry In: McNeely J , McCarthy T , Smith A , Whittaker L , Wikramnayake E, eds. Conservation Biology in Asia. Kathmandu: Society for Conservation Biology Asia Section and Resources Himalaya Foundation . pp 319 - 339 .
35. Judas JO , Combreau M , Lawrence M , Saleh F , Launay Y , et al. ( 2006 ) Migration and range use of Asian Houbara Bustard Chlamydotis macqueenii breeding in the Gobi Desert, China, revealed by satellite tracking . Ibis 148 : 343 - 351 .