These juvenile Glaucous
Gulls Larus hyperboreus were photographed in late September 2006 mostly at Kotzebue (one at Barrow), Alaska. They are presumeably of the form barrovianus, but I have my suspicions that some secondary contact with American Herring Gull or possibly Vega Gull or even Thayer's Gull took place in the recent past (genetically speaking) due to the incidence of birds with less-than-textbook wingtip patterns - but more of that will follow; for now, here's what some of the bills look like at this time of year. Most juveniles had the expected pattern with a clean-cut pink base, but a minority had varying degrees of dusky smudging in the pale base and some fuzziness along the dark/pale boundary on each mandible - this tended to be on the darker-plumaged individuals (with or without classic wingtips), but there were exceptions. I presume these birds to be from the latest hatchings:
