Date: 8/18/25 4:36 pm From: Peter Pyle via groups.io <ppyle...> Subject: Re: [EBB-Sightings] Injured or just molting?
Great info Maureen. I do think there is something else wrong with the left wing of this GRSC, though.
Everything looks good with the right wing and it should be molting the primaries and secondaries synchronously soon, if not now.
The very bleached quills without barbs remaining on its left wing, however, indicate that they did not get replaced last year and may be multiple years old. This happens in birds that get injured follicles due to collision or predation, the molt just doesn't happen. You see it fairly often in gulls and sometimes alcids as well, and it is a big reason why some northern diving ducks like this over-summer in our area. It may well not be able to fly, if not due to the original injury then now due to the lack of molt.
Cheers, Peter
On 8/18/2025 2:57 PM, Maureen Lahiff via groups.io wrote: > Bree Ann, > > I think this scaup is molting, and not injured. Notice that its tail > is also growing out. > > What is unusual is 1. that it is here and 2. it is not on the water. > > Like many ducks and other waterbirds that "do not have to fly to eat," > Greater Scaup undergo a synchronous molt. First, the males get new > body feathers that are more camouflage grey, like the one in your > photo. This helps them hide in vegetation because they then drop all > their flight feathers and regrow them simultaneously, which takes a > lot of food resources. (They are flightness for a couple of weeks.) > Finally, they get new body feathers, the bright "breeding" ones for > males. > > I've seen a number of ducks, especially Northern Shovelers that get > here fairly early in the fall, arrive when they are still getting > those updated spiffy body feathers. And if you look at local Mallards > in September, you won't find males with their signature green heads. > You can still tell the males from the females because the males have > yellow-green bills and the females still have orange bills with big > black patches. > > Greater Scaup males make a "molt migration" in July to inland lakes in > the north between their breeding grounds in Alaska and northern Canada > and their final wintering grounds, making a several week stop over > there to molt before coming here for the rest of the non-breeding > season. (The Birds of the World account, alas, doesn't say what the > females do. The males leave before the eggs hatch, so they can make > molt migration earlier than the females, who have sole responsibility > to care for the precocial young. I'm guessing that the females also > make a molt migration to ensure enough food to replace flight feathers > in a synchronous molt.) > > I'd be happy to talk more off of the list about this. > > Maureen Lahiff > Oakland > > On Monday, August 18, 2025 at 10:59:38 AM PDT, BA EC via groups.io > <bae.crofts92...> wrote: > > > Hello all! > > I saw a Greater Scaup perched on a rock over in the Richmond Marina > this morning, which I thought was strange. The left wing appeared to > be growing a lot of new feathers, but I also wasn't sure if it was > injured because there was a large chunk of wing feathers growing. I > have some pictures attached to my eBird checklist and I would love to > hear some perspectives. > > https://ebird.org/checklist/S268097699 > > Thanks all! > BreeAnn > > > > > >
