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2nd winter Caspian Gull © Andrew Lawson

Seen only on the 16th December 2006.  This was the first Caspian Gull of a remarkable run of at least 12 birds seen between that date and the 17th February 2007 in the Dartford area.

This bird was found on Littlebrook Pool at 3.30pm in fading light hence the poor quality of the images which were taken at 1/8 of a second with a Coolpix 990 and Leica APO 62mm with 26X wide lens.

As with most individual gulls, it was identified based upon the 'sum of its parts' rather than using just one or two features due to the variation and overlap with other gull species within many of the features.  However, this bird was particularly 'spindly-legged'; a very good Caspian Gull feature when compared to, for example, Herring Gull and, to a lesser extent, Yellow Legged Gull.  Note that the leg length above the knee (the tibia) was longer than that of a typical Herring Gull.

Other pro-Caspian features evident with this bird were:

• The mainly white head (streaked etc on most Herring Gulls at this time of year)
• Small, pear shaped head with sloping forehead unlike the broad, square head of a typical Yellow Legged Gull
• The grey, densely spotted 'shawl' on the back and sides of the neck
• The brown centred wing coverts with white being evident only on the feather fringes (compared to typical 2nd winter & 3rd winter Herring Gulls)
• The parallel sided, longish and thin bill.  Shorter and broader on Yellow Legged Gull.
• The predominantly dark centred tertials Note: similar in 2nd winter Yellow-legged Gull and can be found in some Herring Gulls.
• This bird also lacks the white tips to the outer primaries that many Herring Gulls will show in 3rd winter plumage (see plate 352, Olsen & Larsson)
• The black tail bar with thinner, broken bars above the band should be evident on a 2nd winter Caspian, it would seem, but this feature also varies greatly within other gull species.
• This bird has very broad, white tips to the greater coverts whilst the rest of the coverts are mainly brown with narrow pale fringes.  The bar that this creates along the tips of the greater coverts is a good feature of 2nd (and 1st) winter Caspian Gulls and is often lacking or less evident in Yellow Legged Gull at this age.
• A 2nd winter Steppe gull (barabensis) has a more advanced, adult like plumage (Olsen & Larsson)
• Heuglin's Gull at this age would have darker grey upperpart feathers (amongst other features). Please click here to view an image taken on 27th February 2001 in Bahrain.  The bird in the foreground is a 2nd winter Heuglin's whilst the bird in the background is a 2nd winter Steppe Gull.  Note how advanced each is plumage wise at this age.  Also note some of the structural differences between each species and Caspian Gull, for example, the legs.  Another 2nd winter Heuglin's Gull can be viewed here.
• Armenian Gull should have a shorter, stubbier, pale based bill (see Olsen & Larsson P300 and plate 423 on P306)

Caspian Gull 2

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