Below is a collection of 1st cycle California Gulls photographed in Half Moon Bay, California in mid-September. All are hatch year birds - some still in complete juvenile plumage while others showing early 1st alternate scapulars. Subspecies unknown.
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| (1) All juvenile scapulars, a few showing a holy-leaf pattern (a pattern that's been associated with Herrings). The mostly black bill is shown by a minority of birds in mid-September. Band information to follow. |
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(2) Still entirely juvenile. White forehead. Bill pattern with a mixture of black not uncommon for mid-Sept.
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(3) "Cinnamon" type. Pale underparts and chest partially due to bleaching but also plumage variation. Post-ocular line.
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(4) Cinnamon type still fully juvenile. Note the characteristic white forehead commonly shown by this age class.
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(5) Similar to the individual above, but more black in the bill and some smoky gray 1st alternate scapulars.
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(6) Smaller bird showing the famous decurved gape. Large, plain juvenile scapulars.
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Size variation is difficult to appreciate in photos, but what is obvious from these images is the immense variation in upperpart patterns and coloration.
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(7) A bigger and darker Herring-sized bird. A few dark gray alternate scapulars mixed in. Note the long-winged look.
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| (8) Moderate post-juvenile scapular molt. More typical plumage aspect. Blue-gray tibia can be shown at this age. |
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(9) Longish bill, straight and skinny, with typical two-toned pattern. Moderate scapular renewal. Neater lesser/median upperwing coverts.
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(10) Large individual with larger bill and head proportions (male?). Upperparts more worn than average.
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(11) Small bill. Variegated look to upperarts becomes more common as the season progresses. Classic anchor pattern on the lower scapulars. Replaced upper tertial?
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(12) Very plain greater and median coverts. Note the dark post-ocular line. Undertail coverts plainer than most Herrings.
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(13) A darker cinnamon type with smoky gray post-juvenile scapulars. Matching some Western Gulls in size. Massive.
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(14) Extensive post-juvenile scapular replacement. Variegated and dark-gray scapular centers advanced. A few renewed lesser upperwing coverts and a renewed greater upperwing covert. Undertail coverts generally not as neatly barred as Herring. Lower hindneck blotchy with a heavily greased look.
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Overall, 1st cycle California Gulls have upperwing coverts that are weakly patterned and not as neatly shaped as similar-aged Herrings. Their bills are mostly straight with little expansion to the gonys. By early October the bill pattern is two-toned on almost all individuals, but some birds can exceptionally retain a mostly black bill into late October. On average, the species appears shorter and smaller than Herring but slimmer towards the rear with longer wings.
