We consider a method of approximating Weir and Cockerham's θ, an unbiased estimator of genetic population structure, using values readily available from published studies using biased estimators (Wright's F_ST or Nei's G_ST). The estimation algorithm is shown to be useful for both model populations and real-world avian populations. However, the correlation between Wright's F_ST and Weir and Cockerham's θ is strong when compared among 39 empirical avian datasets. Thus, the advantage of approximating an unbiased estimator is unclear considering the small actual effect of θ's bias-removing power on empirical datasets.

Corresponding Editor: S. Karl