second calendar year: October
By October, all LBBG have left the colonies at the Maasvlakte (the Netherlands). In the pictures you can see what variation can be expected in 2cy LBBG by October. The variation seems large, but overall, 2cy LBBG may be classified in the following categories: Category I Those birds with second generation-like third generation feathers (click thumbnail #3). Second generation feathers often show characteristic anchor pattern, barring or deep notches in the fringe. Some 2cy birds replace these feathers in summer for more or less the same kind of feathers. Often the medians show barring or club patterns while the greater coverts have dense spaghetti like barring. This group of LBBG don't have grey feathers in the scapular region and in general there are no "adult-like" features. So far, we were not able to determine this type to geographical locations and probably such type of LBBG may turn up in both graellsii and intermedius (although there is a tendency to allocate them to graellsii). Several birds of this group originated from U.K. colonies, from Belgium and the bird in picture 1, ringed AH53 from northern Germany may be classified as "second generation-like third generation" as well. When birds of this type are heavily built, strong and robust in appearance, they may be mistaken for Yellow-legged Gulls (L. michahellis) in 2cy plumage, especially the ones without grey scapulars (but this is a rare case in October). Category II In October, 2cy LBBG move into the 'steady winter months' where moult is more or less suspended until early spring. However, some LBBG moult throughout the winter, at a lower pace. Others may appear very advanced and may show a 3cy spring plumage already by October, including the all grey adult-like scapular region and some grey median coverts. The lesser and greater coverts are still barred or with a club pattern. There are a few examples in the pictures, and the LBBG in picture 2, ringed in the Netherlands can be classified to this group. This category of LBBG is as hard to allocate geographically as the other group. Category III And finally, there is a third -intermediate- group: those 2cy LBBG with grey scapulars combined by strongly patterned wing-coverts. As can be seen in the spring section of 3cy, this may be the plumage in which they return next year. Partial moult in 2cy intermedius & graellsii Although an undefined number of
-predominantly intermedius- LBBG arrive from the wintering
grounds with moulted wing-coverts and scapulars, the general idea is that,
in line with large white-headed gulls of NW Europe, Lesser Black-backed
Gulls start moulted from late April onwards: the complete moult. This
complete moult includes all the wing-coverts, body-feathers, rectrices and
of course the remiges. By September, the replacement of the last lesser
coverts, inner secondaries and outer rectrices is finished, together with
last to outer primaries.
Arrested primary moult in autumn Arrested or, much better, suspended moult
in the primaries is a rare phenomenon in 2cy LBBG graellsii and intermedius.
The common moult stage in 2cy LBBG is P9 fully grown and P10 slightly
shorter than P9, often at the length of P7 or P8 by the first week of
October. Some birds are a little behind in moult with P8 the longest
primary. |
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2cy LBBG: 'Dutch intergrade' |
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2cy LBBG: intermedius |
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Category I
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Category II
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Category III
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PARTIAL MOULT IN 2CY
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ARRESTED MOULT IN 2CY
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