Effectiveness of Vaginal Implant Transmitters for Locating Neonatal Mule Deer Fawns

Abstract We evaluated vaginal implant transmitters (VITs) as a technique for locating neonatal mule deer (Odocoileus hemionus) fawns. We implanted VITs in 29 pregnant, wild female mule deer in March 2003 and in 20 pregnant, captive mule deer in March 2004. We found no wild fawns at the birth site using VITs. Only 12 of 19 VITs were dropped in beds, and none could be confirmed as birth sites. In contrast, captive does shed 17 of 19 VITs at the birth site during parturition. Two were shed prematurely, and signals of 2 VITs failed. Antenna length, depth of insertion, and length of vaginal canal had no effect on the likelihood of premature shedding. Using aerial telemetry, we detected implanted VITs from distances of up to 1.2 km and expelled VITs from up to 2 km away, whereas from the ground, signal range was <0.6 km. Labor during fawning lasted an average of 121 min, and the average fawn began standing 35 min and nursing 43 min after birth. Six of 17 of captive females left the birth site within 6 hr of par...