Assessing the accuracy of field‐based versus laboratory methods for determining the age of roe deer

Accurate age determination in roe deer Capreolus capreolus is essential for selective harvesting and informed population management, yet field‐based methods widely used by hunters remain imprecise. This study compared field‐based and laboratory age determination methods in 204 harvested roe deer, categorized by sex and habitat type (forest versus open field). Age was estimated using 1) field indicators based on visual observations and tooth wear , and 2) laboratory methods including second molar height, dry eye lens weight, and cementum annuli counts. Generalized linear models and ANOVA revealed that dry eye‐lens weight increased monotonically with age (η 2 = 0.885; p < 0.001), showing strong predictive capacity for cementum‐derived age. In contrast, second molar height exhibited a hump‐shaped pattern, with weaker explanatory power. Sex and habitat type had no significant effects on morphometric traits associated with age, indicating that temporal biological processes dominate over ecological or sexual dimorphism. Agreement between laboratory cementum annuli and field age classifications was fair to moderate (Cohen's κ = 0.371 ± 0.039 SE, p < 0.001) whereas the laboratory cementum annuli and dry eye‐lens weight showed moderate agreement beyond chance (Cohen's κ = 0.285 ± 0.036 SE, p < 0.001). These findings demonstrate that while cementum annuli analysis and dry eye‐lens weight provide robust biological age proxies, field‐based methods currently lack sufficient precision for reliable selective harvest decisions. Reliable age estimation techniques are essential not only for effective population management but also for maintaining the biological and socio‐cultural integrity of selective hunting practices.