What is "mergansers"

Usage examples of "mergansers".

They'd ride out along the ciénaga road and along the verge of the marshes while the sun rose riding up flights of ducks out of the shallows or geese or mergansers that would beat away over the water scattering the haze and rising up would turn to birds of gold in a sun not yet visible from the bolsón floor.

In addition, they had twenty-two pin­tails which they would sell for a few pennies each to the Negroes living in Frog’s Neck, and a score of mergansers, which no one would eat because they fed on fish.

JoLayne pointed out a pair of wild mergansers in the water and, on the bank, a raccoon prowling.