When I first saw the dense rafts of Scaup on the water, I fantasized that they would all take off together on their migration, turning the sky dark with their massed numbers. Now I know they don’t do it that way. For the past couple of days I’ve watched these ducks paddle to the northeast corner of the park, mill around as if choosing a team to travel with, and then take off in small groups, not bigger than about a dozen. Sometimes just one or two took off alone. The groups included males as well as females. One bird led the flock in the air, but that wasn’t necessarily the leading bird on the water. They beat their wings rapidly, but don’t synchronize their wing beats. They all headed west into the setting sun, toward the Golden Gate. They migrate at night, like many other species. Their ultimate destination is the far north, but where in the far north is unknown. Alaska is the most likely target, but if these are Greater Scaup,. not Lesser (I could not tell), they may be headed across the Pacific to Siberia.
The next day I saw not fewer but greater numbers of Scaup on the water. It looks like other flocks moved in during the night from wintering sites further south. They’ll probably be coming and going for weeks. I’ve seen a few stragglers still here as late as June (“Scaup in June” Jun 20 2020).