Data from: Assessing the accuracy of field-based versus laboratory methods for determining the age of roe deer
Data files
Mar 27, 2026 version files 22.26 KB
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Assessment_Data_06032026.xlsx
19.60 KB
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README.md
2.66 KB
Abstract
Accurate age determination in roe deer (Capreolus capreolus L.) 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 vs. open field). Age was estimated using (i) field indicators based on tooth wear and cranial traits, and (ii) 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 (η² = 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.
Dataset DOI: 10.5061/dryad.9p8cz8wzm
Description of the data and file structure
The dataset was collected as part of a multi‑year study evaluating the accuracy and applicability of different age‑determination methods for harvested roe deer (Capreolus capreolus) in Lithuania. The experimental effort involved coordinated sampling across multiple educational and research-oriented hunting management units operated by Vytautas Magnus University, as well as one collaborating hunting club. Between 2010 and 2014, hunters legally harvested 204 roe deer, recording the sex, estimated field age, habitat type (forest or agricultural fields), and collection location of each individual. These animals constituted the core sample set for subsequent laboratory and analytical work.
Field personnel initially assigned ages using standard hunter-based procedures, visual inspection of tooth wear, reflecting common selective-harvest practice in the region. Immediately after collection, trained staff removed jaws and eye lenses from each animal following standardized handling protocols. Subsequent laboratory analyses included measurement of second molar (M₂) crown height, determination of dry eye-lens weight after controlled drying, and preparation of tooth sections for cementum annuli counting using microtomy and transmitted light microscopy. Cementum annuli age was treated as the reference (“true”) age for evaluating the accuracy of alternative methods.
The resulting dataset therefore integrates field-based, morphometric, and histological ageing techniques applied to the same individuals, accompanied by associated biological attributes (sex, habitat type, age class) and spatial metadata linked to Lithuanian hunting management areas. Together, these data support validation of age-determination approaches, assessment of classification error, and development of more reliable age‑estimation tools for wildlife monitoring and selective harvesting frameworks.
Files and variables
File: Assessment_Data_06032026.xlsx
Description:
Variables
- Pop (local landscape in Lithuania)
- Region (region in Lithuania)
- Ecotype (Forest or Field)
- Gender (Male (M) or Female (F))
- Field Age Estimation (age of roe deer given by hunters)
- Age by cementum annuli (true age years)
- M2 Height (second molar Me height mm)
- Dry eye-lens weight (grams)
Code/software
No code available all analysis was done with SPSS studio
Access information
Not applicable