I am pretty sure that if you asked anyone interested in birds whether drake Mallards Anas platyrynchos assume any role in raising their young the answer would be "No."
This is certainly borne out in the literature, (see Kortright 1943, Madge and Burn 1988, Johnsgard 1992, Ogilvie and Pearson 1994, Kear 2005).
It is conventional wisdom that once the female commences egg laying the male deserts her and goes off to join the "bachelor club" of other males, all moulting their plumage and becoming flightless for several weeks.
Thus it was a great surprise yesterday, on Lake Ontario, to witness a family of Mallards, two to three hundred metres offshore, where both drake and hen were chaperoning their ducklings.
I watched carefully to see whether it just happened that a male was swimming in close proximity to the female with her young, but this was clearly a family. If the ducklings strayed too far from the group the male would actively take part in rounding them up and displayed as much vigilance in every way as the female.
The only hint about this possibility is found in Kear 2005 wherein it is stated, "Pairbond lasts until early or mid incubation, male playing no part in brood rearing; however, in urban and other artificial situations, increasingly normal to see male accompanying female and brood."
Whether this area of Lake Ontario, at Paletta Park in Burlington, ON would fit the above definition is a moot point. It is certainly in the midst of an urban environment, but the park is right on the lake and has a wooded area with creeks. Mallards breed there prolifically each year, yet this is the first time I have ever seen a family grouping which included an attentive male.
I'd be interested to hear whether others have observed this phenomenon.
Kortright, F.H. (1943), The Ducks, Geese and Swans of North America, The American Wildlife Institute, Washington, DC
Madge, S. and H. Burn, (1988), Waterfowl, Houghton Mifflin Company, New York, NY
Johnsgard, P.A. (1992), Ducks in the Wild, Key Porter Books, Canada
Ogilvie, M and B. Pearson (1994), Wildfowl, Hamlyn Limited, London
Kear, J. (2005), Ducks, Geese and Swans, Oxford University Press, Oxford