• limited body and head moult in 1st cycle Vega Gull.

Vega Gull is a bird breeding at northern latitudes, and, as may be expected for such taxa, many 1st cycle birds start relatively late with their post-juvenile moult. In other words, they retain the juvenile plumage for a long time. Any bird in November-December, which has replaced the scapulars and show extensive moult in the body feathers contradict to this general Vega picture; that would be odd for Vega by such date, but would be perfectly in line with Herring Gull.

The first two images below show a rather avergae Herring Gull argenteus. These images illustrate scapular moult and body and head moult.

• weak pattern on 2nd gen scapulars in 1st cycle Vega Gull.

Mid-winter 1st cycle Vega Gull has limited body and head moult (still largely juvenile) and the juvenile hindneck and sides of the breast are blotchy brown (not delicately streaked). Two images below illustrate this: left is Vega Gull and right is Herring Gull. Note the differences between the blotchy and delicate streaking.
Despite limited body moult, many December Vega Gulls have 2nd gen scapulars moulted in. The pattern of these 2nd gen scaps in Vega Gull is often weak, the lining is thinner and the anchor less obvious than it is in Herring Gull. The anchor pattern may be completely lacking, Vega Gull the show few plain grey feathers, with just a dark shaft streak. Such grey feathers are rare in Herring Gull, but can be found commonly in taxa like cachinnans and cachinnans hybrids.

Vega Gull (vegae) 1st cycle, January 31 2010, Choshi, Japan (Gullog). Simple pattern of almost plain grey 2nd gen scaps. Also: no notching on tertial fringes and tertials darkest part of the bird (together with primaries) like in cachinnans / cach hybrids. Dark, rather solid patch on flanks, rather uniform underparts. Note: limited body moult (contra cachinnans). Atypical bird in a European context.

Caspian Gull (cachinnans) hybrid 1st cycle  VP9Y December 12 2012, København, Denmark (Lars Krogh). Ringed in Denmark, showing rear scaps with grey base and just a black shaft streak.

• tertials with only narrow fringes and darker than the brown tone in the coverts in 1st cycle Vega Gull.

In Vega Gull, the tertials are often obviously dark brown, darker than the brown tone in the coverts and darker than retained juvenile scapulars. Overall the tertials are normally the darkest part of the back (but still paler than the blackish-brown primaries and tail-band). In European Herring Gulls the brown centres of tertials are less contrasting to the coverts.
The pattern on the tertials in Vega is often is simple, with only narrow pale fringes, lacking deep notching as in most Herring Gulls and in Vega also a pale tip with thin anchor pattern. However, tertial patterns in Herring gulls are variable and simple patterns do occur sometimes (see image below, right; especially Baltic Herring Gulls seem to show straight pale lines in the tertial fringes more often?).

Vega Gull (vegae) 1st cycle, January 31 2010, Choshi, Japan (Gullog). Note very weak anchor pattern on 2nd gen scaps and note pattern on the tertials: they are darker brown than coverts and they lack the post-stamp notches.

Herring Gull (argentatus) 1st cycle  J4773 December 12-13 2013, Sandøya, Norway (Ingar Støyle Bringsvor). Some Herring Gulls may lack notching in the tertial fringes.

• uniform underparts and solid dark flanks in 1st cycle Vega Gull.

1st cycle Vega Gull may show uniform underparts, more in line with American Herring Gull smithsonianus, than with European Herring Gull. In European Herring Gulls the heavier marked flanks and belly are lined and mottled with blotchy bold patterning, not solid dark as the images below illustrate.

Vega Gull (vegae) 1st cycle, January 31 2010, Choshi, Japan (Gullog). Simple pattern of almost plain grey 2nd gen scaps. Dark, rather solid patch on flanks, rather uniform underparts. Note: limited body moult. Ideally, Vega Gull also shows a neat uniform chest and belly.

Herring Gull (argentatus) 1st cycle  J0AG February 05 2005, Norway (Nils Helge Lorenzen). Moult in body and head: delicate 'pencil streaks' on head. Underparts not solid or uniform, but lined. Tertials not obviously darker than brown tone of coverts.

Herring Gull (argentatus) 1st cycle J1490 November 27 2011, Boulogne-sur-Mer, NW France (Jean-Michel Sauvage). From Finnmark, Norway (70°23'N). Streaked chest and underparts not uniform brown; flanks not obviously different in brown tone. Such northern birds show limited post-juvenile moult.

Herring Gull (argenteus) 1st cycle  R.0 September 23 2013, Katwijk, the Netherlands (Mars Muusse). Some Herring Gulls are darker, but generally darker overall, and therefore the patch on the flanks does not stand out as darker than the underparts.

• rectrices with broader dark bands in Vega Gull.

In Vega Gull the outer tail-feather R6 normally shows proximal barring and flecking. European Herring Gull has a narrower dark tail band and the proximal half of R6 is normally clean white or with single black spots. However, there is variation in this aspect, ad the images below show Herring Gulls in the darker end of the spectrum regarding lining and flecking on R6.

Vega Gull (vegae) 1st cycle, January 27 2011, Choshi, Japan (Terry Townshend). Broad tail band, outermost tail-feather R6 with proximal spotting on both inner and outer web.

Vega Gull (vegae) 1st cycle, January 28 2012, Choshi, Japan (Seichoudoku). Broad tail band, outermost tail-feather R6 with proximal spotting on both inner and outer web.

• dark patch on head most solid on rear ear-coverts to crown in Vega Gull.

(delicately streaked crown in European Herrings, especially when head feathers have been moulted to 2nd generation the streaking appears as fine pencil lines);

Herring Gull (argenteus) 1st cycle 429 November 15 2006, Oostende, Belgium (alther Leers). It's difficult to find Herring Gulls with solidly dark ear coverts, but this bird is a close match. Fine streaking is the norm in Herrings.

Vega Gull (vegae) 1st cycle, January 31 2010, Choshi, Japan (Gullog). Ear coverts may be pale in Vega as well. Grey-brown base of scaps suggest these feathers were replaced quite recently, and still not bleached.

• obvious pale panel on inner primaries, also on outerwebs in Vega Gull.

Pale window on inner primaries very prominent in Vega Gull, sometimes the window continues on the outermost secondaries and on the inner greater primary coverts. Window continues on innerwebs of central primaries, still obvious pale innerwebs on P5-P6.

Herring Gull 2cy, January 23 2013, Katwijk, the Netherlands (Mars Muusse). Showing pattern on 1st gen inner primaries.

Vega Gull (vegae) 1st cycle, January 27 2011, Choshi, Japan (Terry Townshend). Very similar to European Herring Gull. 1st gen flight feathers. Tail pattern typical. Beginning to gain some grey scapulars.

Herring Gull argentatus 1st cycle, December 03 2013, Katwijk, the Netherlands (Mars Muusse). Showing upperwing and tail pattern. No scaps replaced.

• tidy and pale looking wing-coverts and juvenile scapulars in Vega Gull.

The wing-coverts in Vega Gull seem paler and very neat and tidy patterned compared to the darker and quite messy ones in Herring Gulls. Below are two example Herring Gulls closely matching Vega regarding silvery white greater covert bars. However, bird C5Y8, although with much white in greater coverts, does not repeat that pattern on the lower lesser coverts. Bird ES14266 really comes close to Vega's standards, but is obvious different on underparts.

Vega Gull (vegae) 1st cycle, January 31 2010, Choshi, Japan (Gullog). Neat, precise and largely silvery white pattern on both greater (2) and lower lesser (1) coverts.

Vega Gull (vegae) 1st cycle, November 26 2011, Choshi, Japan (Seichoudoku). Neat and largely silvery white pattern on both greater (2) and lower lesser (1) coverts. They seem paler and very neat and tidy patterned compared to the darker and quite messy ones in Herring Gull.

• bright pink legs in Vega Gull.

The leg color on Herring Gull is dull greyish pink or flesh coloured. The deep reddish tone on legs is unusual in Herring Gulls; normally they are duller with a greyish tinge.