Accuracy and implications of visually estimating age of male white‐tailed deer using physical characteristics from photographs

ABSTRACT Visually estimating age of white‐tailed deer ( Odocoileus virginianus ) using physical characteristics, commonly referred to as “aging on the hoof” (AOTH), has gained in popularity as part of management programs. However, AOTH has not been evaluated in reference to its accuracy or the accuracy of its users; and most importantly, AOTH is an unstandardized method for estimating age. To assess accuracy of AOTH as it currently is applied, we developed an accuracy examination consisting of a series of photographs of 70 wild, known‐aged, antlered, male deer from south‐central Oklahoma, USA, ranging in age from approximately 1.5 to ≥7.5 years. We distributed a pre‐assessment questionnaire and the accuracy examination to registrants from the 2009 annual meeting of the Southeast Deer Study Group and to select individuals known to use AOTH. One hundred six wildlife professionals that commonly used the technique completed the assessment and examination. Overall accuracy averaged 36% when placing deer into year classes (min. = 16%; max. = 56%). Accuracy tended to be greater for younger year‐classes (1.5–2.5 yr); accuracy generally declined as age increased. On average, 62%, 43%, 25%, 30%, 25%,15%, and 31% of deer were placed into the correct year‐class for the 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, and ≥7.5 year‐classes, respectively. We provide the first known accuracy assessment by users of the AOTH technique. It appears that the AOTH technique lacks accuracy for placing deer into specific year‐classes, which has implications for selective harvest decisions and research use. Accuracy may be improved by developing standardized protocols and criteria for using the technique and training observers. © 2013 The Authors Wildlife Society Bulletin published by Wiley Periodicals, Inc. on behalf of The Wildlife Society