sub-adult: July
Last update of
this page: 07-12-03 17:35
In
moult pace and moult strategy, sub-adults (4+cy) strongly
resemble adults. Since many sub-adults are pretty hard to separate from
adults, it's difficult to be certain about the average plumage in July,
because advanced individuals may be aged wrong and subsequently missing in
surveys (or are at least underestimated). This seems particularly the case
in fast moulting intermedius LBBG, where even full-adults may show
very small mirrors on p10 and p9 and the tips of the outer primaries
appear relatively small. This makes correct ageing very difficult.
Nevertheless,
we feel some characteristics, particularly accumulated in a single
individual may point to sub-adultness:
-
very
small white tips on the old outer primaries (beware wear),
-
a
very limited white mirror on the old p10 and absence of a mirror on
p9,
-
isolated
black markings on old, worn rectrices,
-
brown
centred coverts, often found in the carpal edge (outer lesser
coverts),
-
vermiculation
on (central) tertials or an accentuated black centre in the tertials,
which may have the white tips confined to the inner web,
-
immature
colouration of bare parts,
-
secondaries
show brownish centres with a zigzag pattern along the trailing edge.
Used
as a single characteristic, the evidence is not very convincing, but individuals
that combine these characteristics are probably 4cy or 5cy LBBG.
|
female
5cy LBBG SA8,
July 14 2002, Dintelhaven, Maasvlakte, the Netherlands. P3 has
been shed. Ringed as pullus on June 20 1998. |
Photo
1: sub-adult LBBG, July 7
2001, IJmuiden, the Netherlands. |
Photo
2: sub-adult LBBG,
July 15 2001, IJmuiden, the Netherlands. |
Photo
3: sub-adult LBBG, July 14 2001, IJmuiden, the Netherlands. P5 is
growing and p6 is missing. In the white tail, black markings are obvious. |
Photo
4: 4cy LBBG, July 15 2001, IJmuiden, the Netherlands. Some 4cy
show a very small mirror on 3rd generation p10. The greater coverts are very bleached
and worn. |
Photo
5: sub-adult LBBG, July 6 2001, IJmuiden, the Netherlands. |
Immature
fuscus-like LBBG |
Photo
6: sub-adult
LBBG, July 14
2001, IJmuiden, the Netherlands. Note the tips on the outer primaries. |