Male Incubation in Wilson’s Plover (Charadrius wilsonia)

Male incubation, defined as exclusive incubation by the male, is thought to be a necessary step in the evolution of polyandry from monogamy in birds. When the female has time to gather more food, she can lay clutches more rapidly, which may be an advantage under certain conditions (Emlen and Oring 1977, Graul 1973). Polyandry is then possible if the female can mate with other males for successive clutches. This is the first report of male incubation in Wilson’s Plover (Charadrius wilsonia), a strictly monogamous shorebird (Tomkins 1944 and unpubl. data). Males incubated alone at three nests for a total of 31 days of incubation, documented by 215 h of behavioral samples at these three nests. At 14 other nests in 1980, the males’ average share of daylight incubation was 27% (range 7-44%), which is significantly less than 50% (t = 5.21, df = 13, P = 0.0002, using arcsine transformation).

PETER W. BERGSTROM, The Auk 99: 835-838