Glaucous-winged Gull x Glaucous Gull

 

Glaucous-winged Gull x Glaucous Gull hybrid, Port Townsend, Jefferson County (Washington, USA), 28th October 2011 - copyright Steve Mlodinow

(photo ID: 1371)

Steve points out that the head shape and small eye on this bird are suggestive of Glaucous Gull.  The primaries are intermediate, though perhaps more like Glaucous-winged Gull.  The pale base to the lower mandible would be abnormal for a pure juvenile Glaucous-winged Gull in October.  Steve notes that folded primaries this colour wouldn't be unusual in a Glaucous-winged Gull by mid winter.

Apparently the contrast between the folded primaries and the rest of the wing was more prominent in life than shown in the photo above, but it's more apparent in the blurry flight shots below.  The first flight shot isn't blurry though, and Steve highlights the intermediate wing pattern.  He points out that the apparent dark grey at base of secondaries is a shadow cast by the greater coverts which have been lifted up by the wind.

 Glaucous-winged Gull x Glaucous Gull hybrid (same bird as in photo ID 1371 above), Port Townsend, Jefferson County (Washington, USA), 28th October 2011 - copyright Steve Mlodinow

(photo IDs: 1372-1374)

The next bird is an adult and Steve noted that the wingtip pattern was intermediate between Glaucous-winged and Glaucous Gulls, the back and mantle were paler than Glaucous-winged Gull and the eye was dark.

Glaucous-winged Gull x Glaucous Gull hybrid, about 30 miles off Westport (Washington, USA), April 2008 - copyright Steve Mlodinow

(photo IDs: 1479-1480)

For the next one Steve notes that American Herring Gull x Glaucous-winged Gull should be darker on the wing-tips and would likely have a more obviously pale eye (this bird's is a bit brown) and bicoloured bill.

Glaucous-winged Gull x Glaucous Gull hybrid (the birds in the background are probably Western Gull x Glaucous-winged Gull hybrids), Mukilteo, Snohomish County (Washington, USA), 14th January 2011 - copyright Steve Mlodinow

(photo IDs: 1225-1226)

On the next bird Steve draws attention to the intermediate bill and primaries.  To its right is a bird that looks good for a pure adult Glaucous-winged Gull and behind it is a dark immature (partially in frame) that is likely a Western Gull x Glaucous-winged Gull hybrid.

Glaucous-winged Gull x Glaucous Gull hybrid, Cedar River Mouth, Renton, King County (Washington, USA), 30th December 2006 - copyright Steve Mlodinow

(photo ID: 1227)

Glaucous-winged Gull Larus glaucescens
Glaucous Gull Larus hyperboreus