Temporal patterns of genetic diversity in Kirtland’s warblers (Dendroica kirtlandii), the rarest songbird in North America

In a hierarchical rarified sample of 20 genes and one time period, allelic richness was highest in 1903–1912 sample (AR？=？5.96), followed by the 1929–1955 sample (AR？=？5.74), and was lowest in the 2008–2009 sample (AR？=？5.54). Heterozygosity measures were not different between the 1929–1955 and 2008–2009 samples, but were lower in the 1903–1912 sample. Under some models, a genetic bottleneck signature was present in the 1929–1955 and 2008–2009 samples but not in the 1903–1912 sample.We suggest that these temporal genetic patterns are the result of the declining Kirtland’s warbler population compressing into available habitat and a consequence of existing at low numbers for several decades.