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									European Association of Zoo- and Wildlife Veterinarians (EAZWV)
5 scientific meeting, May 19 - 23 - 2004, Ebeltoft. Denmark.


                                    C. WALZER and S. SILINSKI

Salzburg Zoo, Natur und Artenschutzzentrum, Anifer Landesstrasse 1, A-5081 Anif, Austria

Keywords: Telinjection, capture, transmitter, radio-telemetry, techniques

When chemically capturing free-ranging wildlife, the use of safe and efficient methods are of
utmost importance. The difficulties recovering animals, which are darted in the dark, seek
dense understory cover or move large distances before becoming recumbent, are often
omitted in the literature. On the one hand not recovering an animal, is possibly an animal
welfare issue and on the other a financial and time burden for any project. However, recovery
rates can be significantly increased through the use of transmitter darts (3, 4, 5). Radio-
transmitter dart technology is not new, initial development occurred during the late 1960s (6)
in the USA and New Zealand.

Various systems are available in Europe. The two leading CO2-powered telinjection firms
Telinject (Veterinaer Spezialgeraete GmbH, Roemerberg, Germany) and Daninject (Interzoo,
Gelsenkirchen, Germany) both provide darts which can be delivered with the standard 11
mm barrel. However, differences between the two products are marked: Whereas Telinject
can provide a radio-transmitter dart within a short time frame as they are routinely produced,
delivery of the Daninject model required several months. The constructive approach in the
two models is also different – Telinject provides radiotransmitters, which are screwed on the
tail of a dart with an external whip antenna, Daninject incorporates the radio-transmitter
inside standard dart airspace. Due to the external whip antenna the flight of the Telinject dart
is somewhat less stable than the Daninject model. Alternatively Pneudart
( offers an aluminium radio-transmitter dart that can be fired in the
Pneudart range of projectors and in the CO2-projectors fitted with a 13 mm barrel. Similar to
the Daninject model the Pneudart model does not have an external antenna and is firmly
encased in the aluminium housing (Fig. 1). In contrast to the Daninject model the user is able
to remove the transmitter and replace the battery. A range of 1 and 3 ml darts which can
incorporate the transmitter are available from Pneudart. The Pneudart model flies well and
has a stable flight path. All three transmitters have a similar range of approximately 1000
meters in open terrain. This appears largely adequate for their uses in animal capture events.
As in other telemetry devices, the range can be greatly reduced for example in heavily
forested areas, in bad weather and due to inadequate receiving equipment. Similarly, battery
power lasts in excess of 12 hours at 20oC in the models tested. All models are prone to be
destroyed when missing their animal target and hitting hard surfaces. Due to it’s construction
with a solid aluminium casing, the Pneudart appears somewhat better protected. Several
other firms potentially offer radio-transmitter darts. However, only the three above-
mentioned were able to provide these within a reasonable time frame (three months).

On the downside, all transmitter darts increase the projectile weight and therefore increase
impact energy. This limits their use in view of the possible darting distances and the sizes of
animal one can dart. The few reports in the literature that describe using transmitter darts
used these for very short distances (< 25 meters). When darting wild brown bears (Ursus
arctos) we used Pneudart transmitters successfully over a distance of 40 – 45 meters (1).
The transmitters also proved invaluable in determining when the animals became recumbent
the dark. Careful monitoring of signal strength variation gives an indication to the animal’s
activity (2). (Normal precautions must however be observed as animals could just be waiting
for you!!).

The use of transmitter darts not only improves animal recovery rates but is also useful when
the recovery of darts is of utmost importance (darting in urban areas, drug residues etc.).
Generally, transmitters are a useful adjunct to the standard arsenal of remote delivery
systems and can improve animal welfare, reduce the financial and time burden of wildlife
capture procedures.

1.   Kaczensky P, Knauer F, Jonozovic M et al. Experiences with trapping, chemical immobilization, and
     radiotagging brown bears in Slowenia. Ursus 2002; 13: 347-56.
2.   Kaczensky P, Wagner A and Walzer C. Activity monitoring of brown bears - testing field methods in zoo.
     Mammalian Biol 2003; in print.
3.   Kilpatrick HJ, DeNicola AJ and Ellingwood MR. Comparisons of standard and transmitter-equipped darts for
     capturing white-tailed deer. Wildl Soc Bul 1996; 24(4): 306-10.
4.   Kilpatrick HJ, Spohr SM and DeNicola AJ. Darting urban deer: techniques and technology. Wildl Soc Bul
     1997; 25(2): 542-6.
5.   Nielsen L. Electronic ground-tracking of white-tailed deer chemically immobilized with a combination of
     ethorphine and xylazine hydrochloride. In: Nielsen L, Haigh JC and Fowler ME (eds). Chemical
     immobilization of North American wildlife. Wisconsin Humane Soc, Milwaukee USA 1982; 355-62.
6.   Williams LE. Wildlife research: contract development of radio-dart. Fla. Game and Fresh Water Fish comm
     1969.(available at, 27.01.2004)
  tailpiece   battery + transmitter                       drug chamber   barbed needle

         Insert into dart casing

Fig. 1 Schematic diagram of a Pneudart radiotransmitter dart.
Fig. 1 Schematic diagram of a Pneudart radiotransmitter dart.

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