Comparisons of variance between the breeding (April-May) and non-breeding (July–September) seasons, using Bartlett's chi-square test of variance equality.

P-values < 0.05 and associated chi-square values are in bold. n = number of birds in each category. HB = historical breeders. SS = sequentially successful breeders. SU = sequentially unsuccessful breeders. PB = prebreeders. FB = failed breeders. AK = Alaska fisheries-associated birds. HI = Hawaii fisheries-associated birds. Comparisons of variance between the breeding (April-May) and non-breeding (July–September) seasons, using Bartlett's chi-square test of variance equality.