Statistics
Univariate comparisons of bill and wing lengths between sexes and years were implemented. To determine differences in phylogenetic relationships and morphological features between years, it was assumed the composition of different lineages might vary between the 2 years. The morphological data set of dunlins from lineages inferred from phylogenetic relationships was analyzed further. Bill, wing, and total head lengths among different lineages and sexes were compared. The fit to the normal distribution and homogeneity of variance of morphological data were tested, and t -tests or Mann–Whitney U-tests were performed sequentially. All statistical analyses were performed with SPSS 22.0.