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"Breeding plumage" is a term that is generally used to define the plumage which a bird species carries
during its breeding season. This is more correctly designated as "alternate plumage." Note that all species of bird undergo molt of plumage with its attendant
replacement of feathers on various parts of the body (scoters included), some
more visibly obvious than others. It is usually these more obvious molts
that we recognize as the result of transitions, especially from juvenile to
sub-adult or adult, and also within the "adult range,"
from non-breeding (basic plumage) to breeding (alternate
plumage).
In scoters specifically, there is a molt from the
definitive alternate plumage that begins in July or August and continues into
September, with some individuals continuing their molt into winter. This plumage
is retained into spring. In male White-winged Scoters there is a somewhat (and
often difficult to see) bluish gloss to the black feathers.
Some white head feathers have blackish tips, which quickly wear off.
There are brownish feathers on the sides and flanks. In spring and early summer
there is another transition to the definitive basic plumage, where head, body
and tail feathers are replaced first. This plumage does not have the gloss
of the alternate plumage, the white area at the eye is less distinct, upperpart
and side feathers have pale margins, producing a scalloped or barred effect, and
often the feathers of the belly have sooty ends which produce a mottled
effect.
The picture of the Utah male White-winged Scoter is in
"breeding plumage," but since there is no breeding that takes place at this time
of year, it would most appropriately be called a bird in Definitive Alternate
Plumage (which at this time of year would be expected). One good reference
for the above species specific information (and more) is
1976. Handbook of North
American birds. Vol. 3. Yale Univ. Press, New Haven,
CT.
BTW, to complicate terminology even more, in male
waterfowl there is what is sometimes referred to a an eclipse plumage, in which
males look very much like females after molting out of the "breeding" or
alternate plumage. Also, wing feathers are generally retained for a full
year.
Harry Krueger, Regional Editor, Idaho-W. Montana
Region, North American
Birds
Secretary, Idaho Bird Records
Committee
Boise,
ID
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