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A beaded collar for dual micro GPS/VHF transmitter attachment to nutria

Haramis, G. Michael, White, Timothy S.
Mammalia 2011 v.75 no.1 pp. 79-82
Myocastor coypus, animal comfort, collars, equipment design, field experimentation, friction, global positioning systems, neck, nylon, plastics, radio transmitters, risk, satellites
We report on the development of an approximately 85-g beaded collar for dual micro GPS/VHF transmitter attachment to semi-aquatic nutria (Myocastor coypus). Prototype collars were tested on captive nutria and refined during field trials. Central to the design was novel use of the VHF transmitter antenna as a collar. A circular collar was formed by passing the 44-cm antenna cable through a pre-made hole in the transmitter, leaving an approximately 16-cm upright antenna. GPS units were mounted separately via a hole in the base of each unit. For good satellite contact, GPS units (∼28 g) were maintained at the nape of the neck by counterbalance of the heavier VHF transmitters (∼50 g) positioned under the neck. To reduce friction, we lined the collar with alternate-sized plastic and, later, more durable nylon beads. The final collar configuration was worn for approximately 1 month deployments with only minor neck abrasion; one collar was worn successfully for 5 months. Foot entanglement remained the greatest risk of injury from the collar. By fitting collars tightly, we reduced the incidence of foot entanglement to 2 of 33 deployments (6%). Successful GPS tracks were acquired on 29 of 33 deployments (88%).