Herring Gull- Zilvermeeuw (argentatus & argenteus)
Herring Gull plumages:
hg sub-ad January
probably hybrid Herring Gull x Yellow-legged Gull (argentatus x michahellis) 3cy, November 28 1999, Westkapelle, the Netherlands (51.33N-03.25E). Pictures by Pim Wolf.
This individual much resembling a known hybrid Herring Gull x Yellow-legged Gull: EP30. EP30 was born in the Netherlands and ringed as pullus in the colony of Neeltje Jans on June 23 1997, most likely an offspring of a true male michahellis (ringed orange EAY8) and a female argenteus. Remember however that theoretically another individual could be the father.
The bird in this image also shows intermediate characteristics advocating a hybrid. Most of the greater and lesser coverts still show an obvious immature brown barred patterning, although a few inner greater coverts have been replaced again in the partial moult in autumn and now appear grey-based. The partial moult is extensive, including the three upper tertials, the three inner greater coverts, most of the median coverts and the inner lower lesser coverts. The new feathers are grey-based with a dark arrow-head pattern. All scapulars are plain grey, creating a "saddle-effect" on the back.
From June to October, a complete moult
will bring both 3cy michahellis and 3cy argenteus in
so-called "third winter" plumage. By October, when the complete
moult is finished in argenteus, the head will show extensive
'winter streaking', mottled brown contrasting with the white breast as in
an executioner's hood. The scapulars and mantle are pale adult-like grey.
All comments on this bird (and other supposed hybrids) are much appreciated.