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An Expandable Telemetry Collar for Calf Elk in Colorado


David J. Freddy, Colorado Division of Wildlife, Mammals Research Section, 317 West Prospect Road, Fort Collins, CO 80526 USA

I summarize design and performance of telemetry collars for 6-month-old female and male calf elk (Cervus elaphus) that expand to accommodate neck growth as elk become adults. Collars were used for estimating survival rates and conducting capture-resight population surveys. Transmitters powered by 1 D-cell battery attached to 7.6 cm wide x 80 cm long white belting were purchased (Model LMRT4M, Lotek, Inc., Newmarket, Ontario) and then modified to accommodate expansion. Transmitters were ventrally positioned at 15 cm from the coupling (CE) and 65 cm from the terminal (TE) ends of belting. For female and male collars, 2 parallel, 15.2 cm long x 4.8 mm wide expansion slots were cut into belting between 17.8 and 2.5 cm from the TE. Slots were spaced on 3.2-cm centers, oriented parallel to the long dimension of the collar, and centered within collar width. In addition to slots, male collars had an expansion section. At 20.3 cm from TE, belting was cut and an elastic section was sewn and glued into belting and folded in an accordion manner; this section consisted of a 5.1 cm wide x 15.2 cm long piece of elastic encased in and sewn to the ends of a 7.6 cm wide x 25.4 cm long piece of Hypalon® (>1,050 denier). Two collar fasteners (CF), each with 2 bolts spaced at 3.2 cm (ATS, Inc., Isanti, MN), were placed at 5 cm (CF1) and 58 cm (CF2) from CE on both female and male collars with bolts protruding towards the outside surface of collar. The TE overlapped onto the CE by aligning the CF1 bolts through the dorsal end of expansion slots. A brass fastener plate was placed over the CF1 bolts and flush with the outside TE surface to serve as a spacer and was secured to bolts with self-locking nuts tightened to allow the collar to expand with minor resistance via sliding along slots. CF1 halted expansion and was the permanent attachment CF when collars expanded. Two pieces of amber latex tubing (9.5 mm O.D.) with punched holes were placed onto CF2 bolts, stretched in parallel onto CF1 bolts, and secured with washers and self-locking nuts to maintain collars at minimum circumference. Tubing lengths were 8.3 and 12.7 cm for female and male collars. Tubing deteriorated and broke 9-14 months post-application allowing collars to expand. Prior to adding expansion components, a sleeve of white neckband material (Ritchey Mfg., Brighton, CO) 10.2 cm wide x 19.7 cm long, having black alpha and numeric symbols each 8.2 x 8.2 cm, was slid onto and then sewn to the dorsal surface of collars. Initial circumferences when placed on calves, expansion circumferences for adults, and weights of completed collars were: 57 cm, 89 cm, and 840 g for males and 56 cm, 69 cm, and 820 g for females. During December 1993-1995, collars were placed on 106 male and 107 female calves by sliding completed collars over heads of calves. Collar weights were <1% of body weight at capture for 95% of the calves. Four collars (2%) failed due to design after a maximum of 40 months on individual elk. Collars slipped off 2 11- to 13-month-old males and 1 24-month-old female, and 1 collar dropped off a 29-month-old male when expansion material tore. Abrasion wounds on elk caused by collars were not observed by project personnel or hunters. Damage to manes was generally minor and manes of 27- to 39-month old branch-antlered males remained suitable for taxidermy. No elk were known to have been traumatized because collars were too small in circumference. Observers used symbols to individually identify 90% of the collared elk seen during helicopter surveys.


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