TRANSMITTER MODULES

Modules are primarily used for the instrumentation of birds, herps and fish. Modules are non-collared radio transmitter/battery combinations. Modules are electronically complete and are ready to be turned on after attachment to the study individual. Besides the transmitter and the battery, modules normally contain a transmitting antenna and its base reinforcements, an externally-controlled magnetic on/off reed switch, provisions for attachment to the study individual and waterproof encapsulation. Some modules require the application of harness material by the user, while others come complete with harness material.

Index of Module Types

BACKPACK MODULES

Modules built in the backpack style have been applied to birds ranging in size from small passerines to the largest raptors. The feature that distinguishes backpacks from other modular styles is tubular harness passageways, placed at the front and back of the transmitter/battery package to accommodate the researcher's own harness material.

Another version of our standard backpack is a package in which we leave only one harness passageway for a single, central harness. This passageway can either be used for a wire waist band or for a "figure 8" harness (Rappole and Tipton, 1991) that slides over the legs of small birds.

DuckPacks: Dwyer-style and other bird-ready Harnessed Modules
AVM also manufactures several M-Modules which incorporate an adjustable PVC head-loop/body-loop "figure 8" harness (Dwyer, 1972.) This type of harness has been used on dabbling ducks for over 25 years. Another style of ready-made harness which is popular is a continuous (one-piece) cross-chest harness. Made from PVC similar to that used in the DuckPacks, this type of harnessing can be built into most mid-sized modules.

We can also build in a single belt for packages that are just a bit too big to glue onto a bird's back. Birds over about 75 grams are good candidates for a single-wire harness. Paul Bartelt's (Bartelt, 1994) unique idea of harnessing anuran amphibians contributes to the production of a low-weight, non-abrasive package with which he has successfully instrumented some of the more terrestrial frogs and toads.

Mauser MiniPacks
The "Mauser MiniPack" (Mauser, 1990) for hatchling waterfowl, illustrates both AVM's Interactive Design Process as well as the lengths to which AVM will go to produce the best product for the study. The module's attachment mechanism is a small stainless steel arrow-shaped anchor. The module is attached by inserting the anchor into a tiny slit in the skin on the back of the study bird. Two sutures glued to the top of the package and stitched into the skin beneath the package hold the module in place until the incision closes in a few days. The total package can weigh less than two grams. At this weight the package can be configured to transmit for 60 days.


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Necklace Flatpacks:
Breast-mounted Transmitters for Upland Game Birds

The Perfect Quail NecklaceShorter bird-handling time is not the only advantage of this application system. Speedy removal of a package from one bird and easy and rapid attachment of the same transmitter to a subsequent study individual is an additional asset. Using the removable-cable necklace method of attachment allows a transmitter package to be removed from a dead animal and applied to another animal instantly, by merely clipping the old necklace and pulling it out from both passageways, inserting a new cable and applying new crimp connectors.

The Necklace Flatpack has the same flat backside as the older, bib-mounted "Monarch Module." Therefore, if a researcher wishes to return to the older style of application, the necklace module can be glued to a bib (poncho) without any modification to the package.

If whip antennas are a problem with your birds, as they are in some prairie chicken studies, AVM offers a capacitively-tuned loop antenna breast-mount package. This unit has no external antenna. The tuned loop concept has been around for over 30 years but has primarily been used on small to mid-sized mammals. Several years ago we adapted its use to gallinaceous bird modules. It is now an option commonly used especially by prairie chicken biologists.

The most commonly-used necklace-mounted transmitters are the G3 and P2RLM. As with all AVM radiotransmitter modules, necklace flatpack transmitters are available with a wide range of user-selectable current drains. The batteries most commonly-used to power the transmitters are the flat cells of "Transmitters and Batteries" Table 2B.

All necessary necklaces, neck-protecting sleevings, and metal crimps, according to the specific design, are included with each Necklace Module.

Table 1. Some typical necklace-mount modules selected from the many possible layouts.
TransmitterDrainBatteryLifeWeightComment
G30.040 mABR20326 months6 glow weight
G30.040 mAK-312 months10 gmid size & power
P2RLM-Mortality0.10K-79 months14 gmid power & mortality
G30.150 mAK-75 months12 ghigh power
P2RLM-Mortality0.080 mACR247715 months16 glong life
The perfect quail necklace:  
G3-1V0.015 mAAg35713 months5 glow weight; long life



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Tail-mount Modules

Tail-mount Modules are especially common in projects involving raptors, even down to the size of kestrels. Tail-mounts are generally lighter-weight and more streamlined than their backpack counterparts. The antenna of the module exits the package running flush against the shaft of the retrix, and is normally tied to the retrix in several places down its length.

Tail-mounts incorporate two or three sets of ties, depending on the length of the module, exiting from the mid-line of the package, so that the module can be tied tightly to the ventral side of one of the central retrices. After tying, a drop of cyanoacrylate glue can be placed on each knot, and the ends of the strings trimmed. Other fastening methods, such as the use of cable ties, can be requested by the client.


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Glue-on Modules

The smallest birds and mammals are often instrumented with modules which are merely glued onto the backs of the study individuals with cyanoacrylate adhesives. Only the smallest of the L-Modules lend themselves to this application. As a general rule, no module powered by a battery weighing in excess of about 4 grams can be successfully used as a glue-on. If a module is too heavy the module may be pulled off the back of the animal by its own weight. Glue-on modules have been used on animals as small as Kentucky Warblers (Oporornis formosus) and Salt Marsh Harvest Mice (Reithrodontomys spp.)

Some Glue-on modules are designed to be glued to a tertiary harness, and not directly to the animal. Fisher and Muth's horned-lizard (Phrynosoma mcallii) harness is an excellent example of good planning for attachments prior to the design of the module. Their paper (Fisher and Muth, 1995) (originally entitled "LIZARD LINGERIE..." in manuscript) describes their harness design and materials in great detail.


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CHELONIAN CARAPACE-MOUNT MODULES

Specialized backpack modules have been designed for application to freshwater and terrestrial turtles and tortoises. Rugged modules for application to large, aggressive freshwater species, such as alligator snappers, have brass flanges for bolting directly to the marginal scutes of the carapace. Smaller aquatic turtles, for instance, emydids, are instrumented with very flat modules designed to be attached directly to the carapace with adhesive. All radiotransmitters for aquatic turtles are completely waterproof. The antennas of these modules exit the package in a unique angle for ease in running around the perimeter of the carapace.

Sidecar Modules with Carriers
AVM's Tortoise Sidecar places an SB2 transmitter along side a lithium thionyl chloride battery (most commonly a 1/2 AA- or AA-cell) so that the surface of the package to be placed against the carapace, normally on the first or second left costal scute, tapers in conformation to the shape of the carapace. A whip antenna of about 30 cm exits from the upper front edge of the package at about a 30 degree angle, suitable to be run through a tube encircling the carapace.

Mounting Transmitters on the Carapace
To assist you in choosing an appropriate combination of transmitter, battery and antenna for your module, it may help you to understand something about the positioning and method of mounting a radiotransmitter module on a carapace. E-mail us to request a copy of On the Instrumentation of Chelonians containing a full set of carapace mounting instructions. Author Barbara Kermeen brings many years of experience to this brief paper, having spent nearly 35 years working interactively with turtle biologists.

Transmitters, Batteries and Longevities
Although all of the parameters of the carapace-mount modules we design and build at AVM are custom-specified by our clients, there are a number of combinations that many researchers order over and over again. The following table shows some very popular combinations. If you are looking for some of our smaller units and can't seem to find units powered by familiar batteries, it's probably because AVM has discontinued the use of mercury batteries. AVM has replaced them primarily with silver oxide cells.

Table 2. Some sample weights and longevities of some commonly-used radiotransmitter packages for chelonians:
Transmitter
Battery
Size
Battery
Weight
Package
Weight
Selectable
Longevities
Transmitters powered by 1.5-volt cells: More power than our old SM1's/long life for small and mid-sizes:
G3-1V
G3-1V
G3-1V		Ag317
Ag397
Ag357		200 mg
510 mg
2.3 g		1.5 g
2.0 g
4.5 g		26 days
85 days
13 months
G-3's powered by 3.0-volt cells: More power/light weight for mid-sizes:
G3
G3		BR3032
CR2477		5.5 g
8.4 g		9.5 g
12 g		7 - 13 months
14 - 21 months
G-3's powered by 3.6 volt batteries in a few typical packages used on larger turtles & tortoises:
G3
G3
G3
G3
G3		K7
K-16-F
AA
2-K16F's
C		6.8 g
16 g
21 g
32 g
56 g		9 g
22 g
30 g
38 g
70 g		5 - 26 months
10 - 48 months
1 - 6 years
1.5 - 8 years
The shortest transmission life given on each line in the "Selectable Longevities" column, above, represents the highest power output available in that transmitter/battery combination, while the longest transmission life given represents the lowest power output normally used on a chelonian. In some cases it is possible to increase longevities at further expense of range.

Special Function Transmitters
The special-function transmitter most commonly-used on turtles and tortoises is AVM's Temperature Option B. Temperature transmitters can be made as: Position Based Activity Monitoring is also helpful in monitoring egg-laying behavior in some species. Other types of activity and mortality monitors are infrequently used on chelonians because chelonian movement is not generally of the type that best triggers these monitors.


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Implant Modules: Peritoneal and Subcutaneous

AVM designs implant modules for both peritoneal and subcutaneous use. Subcutaneous implant modules can be designed for use either with the antenna placed under the skin (for applications such as otters and beavers) or for use with an antenna that will actually exit from the body, such as is used in some bird projects, especially for diving ducks.

Peritoneal implant-style modules, like glue-on modules, have no provision for either harnessing or tie-on. At AVM, we routinely make implant modules as small as one gram, total package weight, and as large as a 200-gram alligator temperature implants powered by a D-cell.

The antennas of implant modules are almost always made from rather fine and very flexible materials with smooth, protected distal ends that will not cause internal tissue damage. Peritoneal implantation of transmitters in snakes has been common since the mid 1970's, but placement of the antenna subcutaneously requires a special technique (Reinert, 1992; Reinert and Cundall, 1982.)

Subcutaneous implant-style modules sometimes differ from units designed to be implanted into the peritoneum because they can be designed with small rings to suture the package to the underlying muscle in order to prevent movement of the package under the skin. The other difference between subcutaneously- and peritoneally-implanted packages may be battery selection on the basis of shape.


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The Perimeter Loop Module

The Perimeter Loop Module can be used as an implant or glue-on for applications where previously only very short whip antennas could be used. This package has no apparent external antenna. A single, fine wire is built into the transmitter circuit and capacitively tuned up to radiate signal as a loop antenna. The loop runs around the perimeter of the transmitter/battery pod and is covered by the acrylic housing of the pod.

Perimeter loop modules have now been successfully used in ground squirrel implants and are in the field in beta test on turtles and in snakes. Initial comments indicate that these modules are able to be received several times further than similar packages with short whips.


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Snake Implant Modules

Snake implant modules can be designed as simple direction-finding transmitters but are also commonly constructed as temperature monitors.

Snake implant transmitters are designed to be placed in the body cavity of the snake and their antennas are normally run out of the peritoneum, and under the skin of the dorsal surface of the snake (Reinert and Cundall, 1982.).

AVM's G3 transmitter has become popular for use in larger snakes as well as in the upper size range of what were at one time considered "small snakes." If temperature monitoring is required in modules containing the G3 transmitter, no additional logic circuit needs to be included. The G3's on-board logic can be used as a temperature circuit with the inclusion of a thermistor adding nothing to the modules dimensions.

Now, AVM's new G3-1V transmitter allows even smaller snakes to be instrumented using fully amplified transmitters. Like the G3, the G3-1V is "temperature ready," i.e., able to become a temperature monitor with only the addition of a thermistor. It is our first ever transmitter capable of monitoring temperature while being powered by only a 1.5 volt (silver oxide) power source. See Table 1 on the "Transmitter and Battery" page for appropriate power sources as well as for the longevities produced by the G3-1V powered by each battery. The G3-1V's extreme longevity makes this new transmitter a must for many snake projects.

The G3-1V makes the use of AVM's SM1-H and SM1-H Temperature Modules for snake projects obsolete. It also makes the use of the SM1 powered by two Ag357's, long AVM's most popular snake module, obsolete because more life and more range can be obtained at less weight and at shorter package dimension, by using the G3-1V powered by only one Ag357. Multiple batteries used in parallel can still be used to increase longevity or to maintain a smaller module width than would be possible with one larger battery.

Randall Reiserer, of the University of California at Berkeley's Museum of Vertebrate Zoology, doctoral candidate of Harry Greene, has generously allowed AVM to use one if his great temperature calibration curves. See Goliath the Mojave Rattler's transmitter calibration curve by clicking on the snake!

Temperature Calibration Curve

G3 snake modules are powered by a 3.0 or a 3.6 volt power source, which can either be any of the Table 2A or 2B batteries, or can be pairs of Table 1 (1.5 volt) batteries in series.

Most researchers prefer flat packages, as opposed to cylindrical packages, but AVM will make whatever you think will work best for your project. The time-honored "Reinert" layout uses two silver oxide button cells, positioned with one on each end of the transmitter, laying flat, so that the module will have rounded ends.

Modules Table 3, below, is a table of representative, popular module specifications. If you do not immediately see a module that you think would suit your study, go to the main battery tables, in the Transmitters and Batteries section of AVM's website and substitute in any battery (-ies) that you feel might be more suitable for your study.

Table 3. Sample snake modules with single and multiple batteries.
TransmitterBattery
Type*		Approx.
Weight		Module
Dimensions
l x w x t (mm)		Selectable
Longeveties
G3-1V Transmitters can be made at two different power outputs
lower powerhigher power
G3-1VAg3934g21 x 10 x 075 months3 months
G3-1V2 Ag393's5g31 x 10 x 075 months10 months
The Ultimate Small, Long Life Snake Module:  
G3-1VAg3576g27 x 13 x 0713 Months7 months
G3-1V2 Ag357's9g37 x 13 x 0726 months14 months
G3 Transmitters can be made over a wide range of lives and power outputs
G31/3 N6g29 x 121 to 5 months
G32 1/3 N's9g40 x 122 to 10 months
G3K-37g26 x 19 x 84 to 14 months
G3K-712g44 x 16 x 85 to 26 months
G3K-1625g56 x 16 x 1610 months to 4 years
G3Li C88g75 x 30 


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Ear-Tag Modules

Ear-tagging is an especially good method of tagging immature animals where the alternatives would be expandable collars of comparatively short life. Ear tagging is also a viable alternative to the use of expandable collars on adult male cervids. An Allflex-type, cattle ear tag locking attachment mechanism is used for attachment. Depending on the study species, ear-tag modules can be made using any power source except a C- or D-Cell.

     Our featured ear tag contains a mortality sensing transmitter and radiates its signal through a perimeter loop antenna.

Weight: 35 grams
Dimensions: 50 x 22 x 10 mm
Longevity: 6 to 24 months
Ear-Tag
picture by David Vales, Muckleshoot Indian Tribe



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Fish Tags

Fish tracking with radio-frequency equipment is possible in freshwater with low specific conductivities. Generally, the use of radio equipment in water with conductivity of greater than 1400 microSiemens (micromhos/cc) is not possible. Radio tracking in water depths of greater than approximately 6 meters is usually not advised.

Freshwater tracking equipment is generally manufactured in the low-band VHF (either 40 or 49 MHz) frequencies. The shorter waves of the high-band VHF (148-216 MHz) frequencies, i.e., the standard frequencies used in terrestrial work, do not propagate well through water. But there always seems to be an exception to the rule. If tracking is to be done within approximately the first meter depth of the water, and the water is relatively low in conductivity, standard terrestrial tracking bands may be used. Our work with freshwater turtles over the past several years has also demonstrated that high-band VHF transmitters powered by higher-voltage (3.0+ volt) batteries are a new alternative for fisheries work and allow tracking to depths in excess of 10 meters.

MiniFish Tags
The standard AVM fish module consists of an SM1 (single stage) radio transmitter, battery, capacitively-tuned loop antenna, and magnetically-controlled on/off switch. Completely encapsulated in a waterproof material then finished with acrylic for durability, AVM's fish modules are ready for implant, ingestion or attachment to the outside of a fish. The units are roughly padlock-shaped, with the loop antenna analogous to the shank of the lock.

Table 4. Average Package Specifications for four 1.5-volt and one 3-volt MiniFish Modules
BatteryLifeWeightLengthWidthThickness
Ag3174-7 days1.5 grams17 mm9 mm8 mm
Ag36411-20 days2.0 grams22 mm9 mm8 mm
Ag39220-60 days2.4 grams28 mm9 mm8 mm
Ag39345-90 days2.7 grams28 mm9 mm8 mm
BR1025(3V)17-33 days2.2 grams29 mm10 mm8 mm

Weights and lengths shown in the above table are determined for implant or insert forms. If an additional external attachment loop (the antenna is used as the first loop) is required, module weight and length must be adjusted appropriately. Reasonable approximations of these adjustments would be additions of 100 mg in weight and 1-2 mm in length.

The package lengths shown above include the length of the loop antenna. Similar packages can be made using the high-band VHF frequencies and whip antennas, shortening the total package length by 7mm, the length of the loop antenna.

A range of longevities is shown for each battery. Longevities specifications are selectable from within this spread, from the most powerful, shortest lived unit, to the longest-lived unit at each given size.

Tags for Larger Fish
Transmitter packages for fish larger than smolt are designed to suit each individual project. The starting point for the design of a fish implant is the user-determination of the physical dimensions of a module which could be reasonably inserted into the study species. The goal of this design-for-fish technique is to obtain the greatest range possible by using the largest possible loop transmitting antenna while achieving the needed package longevity. In other words, we select the battery that will produce the needed life, attach it to the transmitter, and fill the remaining space with antenna.

Larger transmitter packages can utilize SM1-H or G3 transmitters, powered by either 3.0-or 3.6-volt batteries. The additional power of this package allows the researcher to obtain signals from greater distances while using low-band VHF frequencies with loop antennas and from greater depths than 1 meter while using high-band VHF frequencies and whip antennas.

A good estimate of fish transmitter package size can be obtained by selecting a battery from the Transmitter Batteries' Table 1 for SM1 transmitters and Tables 2A and 2B for the more powerful SM1-H and G3 transmitters. Incorporating the selected battery with the physical dimensions of the transmitter, as given in the same section, will allow you to approximate your package size. Note that the use of the batteries of Table 2A will produce more cylindrical packages, while use of Table 2B batteries will produce flatter, broader modules.

Table 5. Package Specifications for an assortment of SM1-H or G3, 3.0-volt, more powerful standard-sized Fish Modules. These are only a few examples of the more than 80 sizes that can be created.
Table 2a
Batteries:		LifeWeightLengthWidthThickness
Li10259 mo.-1.5 years8.0 grams33 mm11 mm11 mm
LiAA2-4 years26 grams60 mm11 mm11 mm
Table 2b
Batteries:
BR122520-35 days3 grams22 mm14 mm6 mm
BR20323-6 months5 grams30 mm22 mm6 mm
CR24771.5-2.5 years14 grams34 mm26 mm9 mm
The substitution of a G3 transmitter for additional power will cause weight increase of approximately 2 grams.


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Lonner Modules

No discussion of the modularization of radio tracking transmitter packages would be complete without mentioning the Lonner Module. In the early 1970's, in an attempt to cut the instrumentation costs of the elk research program in the State of Montana, Terry Lonner asked AVM to begin manufacturing modules in a style which suited the radio-tagging of massive numbers of individuals without paying the price of a completely manufactured collar. Thus, the Lonner Module, an SB2 transmitter mounted on the top of a lithium C- or D-Cell and plastic-cast in a cylindrical shape, with a 30 cm whip antenna exiting from one end, was born.

For field use, the Lonner Module is inserted into large PVC pipe (Pedersen, 1977) by the user. The pipe is then heat formed to the neck shape of the anticipated wearer and bolted on the study animal.


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Pinniped Flipper Tags

Flipper tags, mounted on plastic Temple-brand livestock ear tags, are available. Our most popular flipper tag uses the SB2 transmitter powered by the K-7 battery.


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Trap Springing Monitors

Remote monitoring of trap sites is possible using transmitters pulsed by one of two options. Spring-type traps can be outfitted with a transmitter module containing a logic circuit which broadcasts a single pulse burst (beep beep beep) before the trap is sprung and a double pulse burst (bibeep bibeep bibeep) after the trap is sprung. The module itself is attached to a fixed element of the trap or to a nearby stake or even high in a tree for greater range. A cord attached to the magnet which controls the pulse burst mode-switch of module is attached to the spring mechanism of the trap. When the trap is triggered, the magnet is pulled off the module, changing the transmitter's pulse mode from single pulse burst mode to double pulse burst mode. The typical trap springing monitor of this type contains AVM's MP2 transmitter powered by one of the larger Table 2A batteries.

A trap monitor dependent on transmitter position is also available. Units containing this type of indicator are valuable for use on sapling-incorporated snare traps. Position indicators can be built into any transmitter and battery combination.


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Custom Designs for Your Project

This section has described many commonly used modules, but it is by no means intended to limit your selection or your interaction in the design of the module that would be best for your study. If your project or study species has special needs that you do not feel have been taken into consideration by the various types of modules described herein, please contact AVM for custom-design assistance. All transmitter packages manufactured at AVM are specifically designed and produced for each individual order to suit the exact needs of the particular study. Our clients have the ultimate control over the final specifications of their product.


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A Summary of Your Choices

You may designate the specifications of your modular transmitting system in the following areas:
Some Sample Module Specifications
Here's chart of some sample transmitter/battery combinations that can work together to make some functional modules. We have purposely repeated a number of batteries and transmitters, to illustrate how substitutions can work.

Note that all batteries listed in the Battery Tables of the Transmitter and Batteries section of this website are not necessarily appropriate for every modular application even though they might be in the correct voltage table, because their shapes may not be suitable.

We're just giving you a few combinations, but this chart is infinitely expandable: the SM1 and SM1-H's can be powered by 17 batteries at 8 current drains, for 272 combinations, and the P2RLM, the G3 and the SB2 transmitters can each be powered by 30 cells, each at 26 current drains, for 1,560 combinations, totalling 1,832. And these figures are just based on the batteries that we list in our literature. There are many more sizes between the ones that we have selected for you.

Table 6. A few sample module specifications. Each entry, below, shows a transmitter, followed by its current drain on the first line. The second line shows the battery used and the third line shows the longevity for this combination.
Size RangeLonger LifeMid-RangeHigher Power
<2 gramsSM1 @ 0.03 mA
Ag396
60 days		SM1-H @ 0.06 mA
CR1025
24 days
<3 gramsSM1 @ 0.03 mA
Ag393
3.7 months		SM1 @0.07 mA
Ag389
7 weeks		SM1-H @ 0.08 mA
BR1225
21 days
5-8 gramsSM1 @ 0.030 mA
Ag357
8.5 months		SM1-H @ 0.060 mA
BR2032
5 months		G3 @ 0.20 mA
Li1018
2.5 months
12-14 gramsG3 @ 0.05 mA
K-7
20 months		G3 @ 0.11 mA
K-7
10 months		G3 @ 0.20 mA
K-7
5 months
14-18 gramsG3 @ 0.05 mA
2.5 years		G3 @ 0.11 mA
CR2477
1 year
23-27 gramsG3 @ 0.11mA
K-16
1.8 years		G3 @ 0.22 mA
K-16
10 months
28-43 gramsG3@ 0.11 mA
LiAA
2.2 years		SB2@0.32 mA
LiAA
8.8 months

Remember, when time and logistics permit, AVM can send the first unit of your order for your inspection and testing, so that you will have the comfort on knowing that the packages used on your study will be perfectly suited to your needs.


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REFERENCES

Bartelt, P.E. 1994. A Plastic Belt for Attaching Radio Transmitters to Anurans. Poster Paper given at HL/SSAR Meetings, Athens, GA. Summary Available from AVM.

Boarman, William I., Tracy Goodlett, Glenn Goodlett and Paul Hamilton. 1998. Review of radio transmitter attachment techniques for turtle research and recommendations for improvement. Herpetological Review. 29(1):26-33.

Colberg, Mary Ellen, Dale F. DeNardo, Nora A. Rojek and Jack W. Miller. 1997. Surgical Procedure for Radio Transmitter Implantation into Aquatic, Larval Salamanders. Herpetological Review. 28(2):77.

Dwyer, T.J. 1972. An Adjustable Radio Package for Ducks. Bird Banding, 43: 282-284.

Fisher, Mark and Allan Muth. 1995. A Backpack Method for Mounting Radio Transmitters to Small Lizards. Herpetological Review, 26(3):139-140.

Madison, D.M. 1997. The Emigration of Radio-implanted Spotted Salamanders, Ambystoma maculatum. J. Herpetol. 31:542-551.

Mauser, D.M. and R.L. Jarvis 1990. Attaching Radio Transmitters to one-day-old Ducklings. J. Wildlife Management, 55(3):488-491.

Pedersen, R.J. 1977. Big Game Collar-Transmitter Package. J. Wildlife Management, 41:578-579.

Plummer, M.V., N.E. Mills, and S.L. Allen. 1997. Activity, habitat, and movement patterns of softshell turtles (Trionyx spiniferus) in a small stream. Chelonian Conservation and Biology 2:514-520.

Plummer, M.V. and J.C. Burnley. 1997. Behavior, hibernacula, and thermal relations of softshell turtles (Trionyx spiniferus) overwintering in a small stream. Chelonian Conservation and Biology 2:489-493.

Rappole, John H. and Alan R. Tipton. 1991. New Harness Design for Attachment of Radio Transmitters to Small Passerines. J. Field Ornithology, 62(3):335-337.

 Reinert, Howard K. 1992. Radiotelemetric field studies of pitvipers: Data acquisition and analysis. pp. 185-197. In Campbell, Jonathan A., and Edmund D. Brodie, Jr., eds. Biology of the Pitvipers. Tyler, TX: Selva

Reinert, H.K., and D. Cundall. 1982. An Improved Surgical Implantation Method for Radio-tracking Snakes. Copeia 1982: 702-705.


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