3cy:
November - December
Last update of
this page: 25-07-05 18:25
The birds shown here are in 3rd winter plumage (3cy). LBBG in 3cy
and 4cy can look very
much the same in early winter, and particularly when the outer primaries are lost, it
may be hard to age many of these sub-adults correctly. Those in 4cy are often recognized
by and distinguished from 3cy by the grey outer primary
coverts (though with black centres in most cases, as seen in full-adult LBBG as well) and the extensive
white tips to the outer primaries and larger mirror on p10 (though this
may be sex related and geographical variation . Also, in most cases, the black
markings on the bill are less developed in 4cy birds; 4cy LBBG are more
adult-like in bare part coloration.
Some photographed sub-adults with rings show the difficulty and
variation of sub-adult in the period where the outer primaries are not
indicative. See the adult and sub-adult sections.
3cy LBBG normally show some/all of
these features:
- Very pale legs and much black on the
bill, combined with a pinkish base, which are more adult-like in 4cy (image
1);
- The old coverts are extensively brown
bleached and on average adult-grey in 4cy;
- New tertials show a grey base with a
white tip which is confined to the inner-web (image
2). Old tertials are either
brownish bleached or show a dark brown-black centre and vermiculation
on the upper half. In 4cy, the old abraded tertials are all plain
normally;
- Scapular coverts may be rather brownish
centred, not pure grey as in 4cy and adults (image
3);
- Some of the recently moulted
tail-feathers show black isolated spots near the centre (often found in the inner
tail-feathers: image 2);
- Primaries show very small white tips in
3cy, especially the outer primaries p6-p10 (image
3). In 4cy these primary tips normally are larger, but this may vary with populations;
- The mirror on p10 is relatively small in
size and a mirror on p9 is lacking. 2cy normally don't show a mirror
at all and 4cy have the mirror on p10 well-developed. The 3cy p10
mirror is an isolated white spot and normally doesn't reach the
feather edge (image 1).
- Primary moult score is high on average (image
1),
compared to the more adult-like primary moult score of 4cy. In this
respect, 3cy moult strategy is closer to that of 2cy and 4cy is closer
to adults. By November, many 3cy have primary moult score of 50, hence
all the primaries renewed and fully grown.
3cy
LBBG: primary moult score, Maasvlakte, the Netherlands. |
|
p7 new |
p8 new |
p9 new |
p10 new |
n: |
m: |
06.11.2001 |
0 |
2* |
29** |
79*** |
110 |
9,70 |
n: total.
m: average, mixed graellsii, intermedius, Dutch
intergrades.
*: in both the old p10 still present, incl intermedius LBBG
ringed blue JSM7.
**: incl intermedius LBBG ringed blue BLAJ.
***: incl local Dutch LBBG ringed orange EU31. |
|