A genetic analysis of mallards, grey ducks, and their hybrids in New Zealand

Abstract
Variation at 39 allozyme loci in small samples of grey and mallard ducks from New Zealand showed no significant differentiation between populations and minimal heterozygosity (<0.010) in all populations. This finding is consistent with other observations of no allozyme differentiation among congeneric species of birds and with the conservative nature of allozyme divergence in birds generally. The data also suggest that both taxa have undergone genetic bottlenecks associated with their arrival in New Zealand.