Figure 1.
Examples depicting plumage and bill shape differences among Reed Bunting subspecies.
a) first-year females E. s. schoeniclus (left) and E. s. lusitanica (right); b) first-year male E. s. schoeniclus; c) first-year male E. s. lusitanica and d) first-year male E. s. witherbyi, captured at Salreu, Estarreja, Portugal, except the latter, which was captured at Lagunas de Villafranca, Toledo, Spain. All pictures were taken by JMN.
Table 1.
Unstardardized parameters and t-tests of the General Linear Models evaluating the effects of age, sex and subspecies/population on the various biometrics.
Figure 2.
Scatterplot of bill depth and wing length for each age, sex and subspecies/population.
E. s. schoeniclus includes birds trapped in Portugal during winter as well as those measured in Sweden.
Figure 3.
Isometrically-adjusted primary lengths of the resident E.
s. lusitanica and the migratory E. s. schoeniclus wintering in Portugal and from Sweden. Sample size is indicated between parentheses. T-tests indicate that primaries 9, 5, 4, 3, and 2 are significantly different between the subspecies (ns – non-significant; * – P<0.05; ** – P<0.01; *** – P<0.001).
Figure 4.
Bill shape in relation to population and sex, as measured by the two most important axis of variation for population discrimination (RW1 and RW3) derived from geometric morphometric analysis.