An expandable radiocollar for elk calves

Expandable radiocollars, designed to monitor juvenile survival and movements, were placed on 132 neonatal elk (Cervus elaphus) in Yellowstone National Park during 1987-1990. A modified design of the same collar was placed on 164 neonates of the Jackson elk herd in northwest Wyoming during 1990-1992. One of the Yellowstone calves and 19 of the Jackson calves cast their collars before 15 July of their birth year. General deterioration of col lar materials resu Ited i n loss of the Yel lowstone col lars 1 2-1 8 months post-deployment. Separation of breakaway tabs resulted in loss of 13 collars from Jackson elk 504 + 60 days post-deployment, but the remaining collars remained on elk for <4 years. These light-weight and adaptable collar designs achieved study objectives. We provide design recommendations for future monitoring of juvenile elk.