Scaup Arrive in Numbers

I made my usual check for Burrowing Owls along the north side this morning.  Before I could peer through the fennel at the rocks where owls had perched recently, the Bay water to the north caught my eye.  First, near in, a harbor seal swam slowly westward, took a few noisy breaths, and then dove.  Further out, a large number of black and grey dots churned the otherwise glassy surface.  Open camera, extreme zoom:  Scaup.  Like many other birds that migrate at night, they probably just arrived.  Most of the Scaup we see on the Pacific Coast spend the summer and breed in Alaska.  They’ve had a flight of around 2,000 miles to get here.  Without trying to count them at this distance, I would guess there were about 200 of them.  They were busy feeding, diving in no particular order, males and females alike.

This past December, Scaup arrived in the North Basin in massive numbers, turning this estuary into Scaup City.  Today’s arrivals may well be just the advance guard.   Last year, bird counters estimated that 34,000 of them visited the Bay Area.  Yet these numbers are evidence of long-term decline.  Habitat destruction and climate change have brought them down to these quantities from what used to be hundreds of thousand and millions.  Details on Wikipedia.

I’ve mentioned these birds here before.  But just to get caught up, here’s the current set of “Cool Facts” about this species from the Cornell bird lab website:

  • Occasionally an older female Greater Scaup will have male-like head color and male patterning on her back, but she still has the typical white face patch of a female.
  • Once incubation begins, the male Greater Scaup leaves the female and goes to molt on a relatively large, isolated lake with abundant food and cover. These lakes are used year after year during molt and may be in the immediate vicinity of the breeding wetlands or many miles away.
  • The nest of a Greater Scaup is usually lined with a thick layer of down plucked by the mother from her own breast. Nests of poor-condition females may lack down and instead may contain small, grayish-white feathers plucked from beneath the outer body feathers.
  • Eggs and ducklings fall prey to predators such as gulls, foxes, and ravens. In some areas, northern pike (fish) also eat ducklings.
  • The oldest recorded Greater Scaup was a male, and at least 20 years, 5 months old when he was found in Michigan in 2007. He had been banded in New York in 1988.

Oh, and I didn’t see any Burrowing Owls this morning.


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