Figure 1.
Example of age group from the tool.
Age group 6 (chicks 20–23 days old) is shown (full tool is provided as Fig. S1). Within the age group, pictured chicks increase in age from left to right; an image of the outstretched wing of the oldest chick is provided. Morphometric data summaries and key diagnostic characteristics are also shown.
Figure 2.
Mean chick-aging accuracy without and with the tool for observers in field and laboratory tests.
Chick-aging accuracy is the percentage of chicks aged correctly by observers when not using (dark gray) and when using (light gray) and the aging tool. Error bars are ±1 SE.
Table 1.
Morphometric features most often used for aging estimates prior to and when using the tool.
Table 2.
Highest-ranked GLMMs (ΔAICc<2) for observer chick-aging accuracy (correct or incorrect estimation of chick age) in learning-phase trials.
Figure 3.
Boxplots of improvement in chick-aging accuracy when using tool for observers of different prior experience in (a) field and (b) laboratory tests.
Improvement in chick-aging accuracy is the difference in the percentage of chicks aged correctly when using the tool versus without the tool. Sample sizes of observers are given in parentheses next to axis labels. “No Experience” = no prior experience working with any birds, “Some Experience” = <1 year working with birds (including Common Terns) [for laboratory trials this was any previous experience with birds], and “Most Experience” = 1+ years working with Common Terns.
Table 3.
Highest-ranked (ΔAICc<2) and other GLMMs for observer chick-aging accuracy accuracy (correct or incorrect estimation of chick age) in laboratory trials.