Red-breasted Merganser (1 Viewer)

AGDK

Well-known member
Hello

I haven't seen the Red-breasted Merganser around here, while they are in eclipse.. They normally arrive in December/January..

But I see a double black line in the white patch on the wing, which according to my bird book indicates a male Red-breasted Merganser?

Am I right?
 

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Alexander Stöhr

Well-known member
I think you are right with Red-Breasted Mergander, please note:
uptilted bill, lack of a contrasting white chin area, no sharp division between brownish neck and paler upper breast. All this single points can be shown by Goosander, so use them all for id!
Your bird has a small bill for a Red-breasted Merganser, birds with longer bill are easier to id against Goosander in my experience.
 

AGDK

Well-known member
Hi Alexander...

Thanks for your comments..

I have attached a picture, which is more straight on the bird, it's maybe easier to see the right size of bill here..
 

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AGDK

Well-known member
For me the bill seems pretty thick in the base for a Red Breasted and as you suggested a bit short.. That was my main objection against in my initially look.. Secondly that it's pretty rare around here at this time of the year..

If it wasn't for the 2 black lines on the white patch on the wings, I would have marked it as a Goosander, without thinking deeper about it.. :)

Forgot to mention that the bird was seen today on the Polish Baltic coast
 

Deb Burhinus

Used to be well known! 😎
Europe
https://www.photo.net/photo/18458220/First-winter-Male-Red-breasted-Merganser

I’ve been trying to find some references for moult strategy in male RBM because the white on the wing is too extensive for a 1w ...it also looks to have some missing tail feathers

.the 1w male in the link is much duller with a smaller wing patch.

. I can’t find any references but I as far as I recall, body moult begins (and is largely completed just prior to moult flight feathers) in July/Aug (which means males are in full flightless eclipse for the shortest time in September). What I wondered but couldn’t find any literature for, is whether adult males also again replace body plumage (into breeding plumage) at the same time as moulting into new flight feathers or if only the fight feathers are renewed following eclipse. If the later strategy, which makes sense to me, (and would explain tail feathers still growing in) this would explain why we are looking at a flying adult male with a red head etc (in a sort of halfway post eclipse plumage)
 
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Deb Burhinus

Used to be well known! 😎
Europe
That was my first thought from the white line on the lores, but didn't comment as I didn't know if young birds could get that much white on the wing at this age :t:



Sorry specimens only but the link shows the extent of white on the wing on male/female and imm birds - the wing of the imm has only slightly more white on wing than that of the female and has a similar wing pattern (only one black wing bars and the white not extendiing to the inner secondaries).

http://www.drundel.com/hunt/duckplum/redbmerg.htm

The OP to me looks like an adult male coming out of post/eclipse -

As for the wing pattern being diagnostic for male RBM, it is, but for an adult not an immature/1cy
 
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Nutcracker

Stop Brexit!
Sorry specimens only but the link shows the extent of white on the wing on male/female and imm birds - the wing of the imm has only slightly more white on wing than that of the female and has a similar wing pattern (only one black wing bars and the white not extendiing to the inner secondaries).

http://www.drundel.com/hunt/duckplum/redbmerg.htm

The OP to me looks like an adult male coming out of post/eclipse -

As for the wing pattern being diagnostic for male RBM, it is, but for an adult not an immature/1cy
Thanks! Odd that it has a pale loral stripe like a juvenile then!
 

lou salomon

the birdonist
thanks for digging this out, deb.
a "definite basic adult male" (in yank terms) it is then.
nutty, i think i've had this problem with ageing mergansers already, with finding out that even adults can have that loral stripe...maybe the all dark crown of this bird also indicates that it is moulting into breeding plumage and 1cy probably would do so later.
 

Birdbrain22

Well-known member
Ahhh, the dreaded eclipse male strikes again. Seems you are correct Deb based on the wing. I should’ve caught that too because the 1st winter males we see around here are much darker around the eye... but was basing on the loral stripe as well. Since they are in breeding plumage when they get down here for the winter, not much experience with eclipse on this species. Great info and links to keep.
 

Deb Burhinus

Used to be well known! 😎
Europe
Thank you from me too, Deb! I left ageing/sexing for this bird, because I wasnt sure, so I learned much from your comments.

You’re welcome Alex - the takeaway is that as Lou said, it can be identified as RBM (male) because the wing pattern is diagnostic - Goosanders don’t show this wing pattern at all so it’s not necessary to worry about features such as comparing bill sizes and shape etc to separate them! (which as you correctly concluded, is variable and can overlap anyway.)
 
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andreadawn

Beside the Duddon Estuary, Cumbria
England
Looking at the pic in the first post, are those apparently long white feathers between the wing and body the tertials? If so it would also point to adult male. Adult female has all dark tertials whilst first winter male typically only has white on the outer web of the most distal tertial. Only adult male has all white tertials.

(Info from "Wildfowl of Europe, Asia and North America" by Sebastien Reeber (Helm), and "Identification of European Non-Passerines" by Jeff Baker if anyone wants to check I'm not misunderstanding something).
 

Deb Burhinus

Used to be well known! 😎
Europe
You are exactly right Andrea, they are - see my post in #11 - and the specimens link to a very clear image showing the pale tertials of adult male - might be difficult to pull this out as a field mark though on a flying bird but would be very visible on a bird at rest (and which is a very good field mark - see post # 13 and the first link under ‘eclipse males’.
 

andreadawn

Beside the Duddon Estuary, Cumbria
England
^ It's interesting what you can learn from this part of the forum about birds you thought you knew quite well; in this case one of my top ten favourite birds. Thanks for the links.
 

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