michahellis (in 4cy and 5cy) may resemble birds in adult plumage. On
average, 4cy birds normally still show a few immature features, but on the
other hand some 4cy match the average adult very well and are hard to
identify. Nevertheless, some of the following characteristics can
often be found in 4cy birds:
- The bill is not saturated orangey-yellow, but
pale yellow, especially towards the very tip and the base of the bill.
- The bill often has obvious black marks on
the upper and lower mandible near the gonydeal angle.
- The red spot on the gonydeal angle doesn't
reach the cutting edge of the lower mandible. In older birds this red
spot extends on the upper mandible.
- The iris is peppered or speckled, unlike
the plain yellow iris in most older birds (5+cy birds).
- Some old wing-coverts have a brown hue,
especially visible in the outer lesser coverts or central greater
- The central and lower tertials and outer secondaries
show patterns commonly found in third generation feathers: the
tertials have dark centres with vermiculate spaghetti pattern towards
the fringes and the outer secondaries show a brown hue on the centres,
unlike the plain grey fourth generation secondaries found in 5cy and
- The primary coverts show an all-dark
brownish centre with a small paler crescent on the tip. In older birds these
primary coverts are all grey or at least show a grey base with
sometimes some black (an accentuated shaft). Black in the primary
coverts in 5+cy birds is often related to the size of the black on the
primaries, which may "extend" on the primary coverts.
- The white tip on P10 doesn't merge with
the mirror but is separated by a broad sub-terminal band and even P5
shows a broad black patch. In older birds the black sub-terminal
band on P10 is much narrower and the white mirror on P10 broader. The
tips on fresh primaries are larger in adult birds.
- The tail may show small black spots on
As can be expected, there is no surprising
moult going on in sub-adult birds, this time of the year. The average
adult michahellis finishes primary moult by the end of October. By
January, the outer primaries may show slight wear already. The winter head
streaking, which was obvious and concentrated on the ear-coverts, around
the eye and up to the crown by September and October, has been worn away
by mid winter, leaving the snow white appearance as in adult michahellis.
details on differences between michahellis and cachinnans, see
e.g. the article by R. Klein & D. Gruber in Limicola, April
Le Portel, NW France:
Le Portel and the near surrounding do not
hold large colonies of
Yellow-legged Gulls. Numbers of sub-adult Yellow-legged Gulls in NW France are
low in winter. At the landfill of Dannes,
near Le Portel, large mixed flocks of mainly Herring Gulls
(1,000's) from NW and N Europe can be found including adult and sub-adult
Yellow-legged Gulls (few tens in January 2002). By March, many adult
Yellow-legged Gulls and with them the near adults return to the breeding
grounds. The breeding season starts early for this species which breeds in
8645: Michahellis 4cy, January 04 2002, Le Portel, NW France.
A sub- adult michahellis
in 4cy as can be told by the very small white tips on the relatively fresh
outer primaries and the vermiculated pattern in the centres of the lower
tertials. The white tip on P10
doesn't merge with the mirror but is separated by a broad sub-terminal
band and even P5 shows a broad black patch.