Skip to main content
U.S. flag

An official website of the United States government

Haldane's rule and American black duck x mallard hybridization

January 1, 2004

Species ratios and rangewide distributions of American black ducks (Anas rubripes Brewster, 1902) and mallards (Anas platyrhynchos L., 1758) have undergone recent changes. Mechanisms behind these changes are not known with certainty, but recent investigations have focused on the possibility of competitive exclusion and the consequences of hybridization. Consequences of hybridization have been difficult to assess because of the difficulty in identifying hybrids beyond the F1 generation and lack of means to quantify introgression in wild populations. We documented a postmating isolating mechanism between the two species that follows Haldane's rule in controlled, interspecific matings in captive populations. Hybridization reduces the proportion of F1 females available to return to the breeding grounds in the subsequent year. This effect, although likely small in overall population consequences in any year, may be of local significance and may contribute to recent reports of range shifts in both American black ducks and mallards. ?? 2004 NRC.

Citation Information

Publication Year 2004
Title Haldane's rule and American black duck x mallard hybridization
DOI 10.1139/Z04-169
Authors R.E. Kirby, G.A. Sargeant, D. Shutler
Publication Type Article
Publication Subtype Journal Article
Series Title Canadian Journal of Zoology
Index ID 70026539
Record Source USGS Publications Warehouse
USGS Organization Northern Prairie Wildlife Research Center