Hi -
I think adult males were well over half the Surf Scoters I saw today, but a lot
of the biggest flocks were far enough out that we were (or at least I was)
identifying them more by bird shape, dark appearance, wing beat, and flock
shape and movements, and not looking at white on the heads.
When I lived in Florida, Red-breasted Mergansers were common in winter but
virtually all of them were females. I think I saw 3 obvious males in my 12
years in the Keys.
More generally, even if they do not winter in different places, many northern
sea ducks segregate by sex in summer and stay separate for quite a while, in
some species rejoining after migration. Males and females are together when
they arrive on the breeding areas, and through egg-laying, then the males
depart while the females are incubating. The males gather in large flocks on
"big water" - large bays, lagoons, and somewhat protected areas at sea, and go
through their flightless molt period there, where they are remote from avian
predators. The females go through the molt on the breeding areas in the company
of their still-flightless ducklings.
Wayne
From: "Phil Pickering" <philliplc@xxxxxxxxxxx>
To: "Alan Contreras" <acontrer56@xxxxxxxxx>, "obol" <obol@xxxxxxxxxxxxx>
Sent: Sunday, November 15, 2015 4:31:10 PM
Subject: [obol] Re: Boiler Bay
Is that late for large movements of Surf?
I wonder if you had any sense of whether a lot of your
birds today were adult males.
