In yesterday's post, I failed to include canvasbacks among my sightings at Eagle Bluffs (the error has since been corrected). In fact, were it not for the large flock of snows and greater white-fronted geese, my report would have concentrated on those large diving ducks.
Indeed, I observed more canvasbacks at Eagle Bluffs yesterday than I have on any visit over the past seventeen years. After breeding in the pothole country of northwestern North America, these elegant ducks travel south in large flocks to winter on coastal bays, large rivers or reservoirs of the southern U.S. and Mexico; migrations are primarily through the Mississippi and Pacific flyways.
Grebe-like in their habits, canvasbacks place their nests on floating vegetation; ten greenish eggs are generally produced. The ducklings leave the nest soon after hatching, feasting on insects at the surface; adults, on the other hand, dive to feed on aquatic plants and invertebrates. Rather clumsy on land, canvasbacks are powerful swimmers and fliers; though their population was threatened by overhunting, lead poisoning and habitat loss in the 1980s, their numbers have since increased and stabilized thanks to the work of conservation organizations across North America.
