Tag Archives: Thayer’s gull

Over-Wintering birds arriving

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-237, ‘2011-09-15’, ‘Other’, 0, ‘Sea lion populations have stabilized in terms of numbers. With just ~250 California ”s and ~150 Steller ”s. Ever since the earthquake on 09/09/11 -which was not felt by me here), the sea lions have moved up from “the arena ” and East bay on Great Race to surround three sides of the Keeper ”s residence. They have blocked 2 of 3 entrances! They can be shooed away, but return during the night. The cool winds and overcast days permit them to sleep comfortably during the day only to be particularly raucous during the night. The transition between Glaucous winged gulls and their winter replacements the Thayer ”s gulls has begun. Some Heerman ”s gulls are present now as well. It appears at least one oystercatcher clutch was successful as an adult pair and their two fledged chicks are still present on Great Race.’, ‘Ryan’, ’10:03:54 ,

Larus thayeri: Thayer’s gull – The Race Rocks taxonomy

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Thayer’s Gulls aligned for wind, November, 2005

Domain Eukarya
Kingdom Animalia
Phylum Chordata
Class Aves
Order Charadriliformes
Family Laridae
Genus Larus
Species thayeri
Common Name: Thayer’s Gull

History: Formerly considered as a subspecies of Herring Gulls. It is sometimes regarded as a subspecies of Iceland Gulls.

Physical Appearance:22 1/2″ – 25″ wide Mantle slightly darker grey Grey on the underside of the wing tips is distinctive. Yellow bill with red spot on lower mandible. Pale to brown eyes, with a purple-red ring around it. Darker pink legs.

Sound: Long mewing call: hiyah
Warning call: gah-gah-gah

Nesting: Usually 2 or 3 olive-brown, heavily blotched eggs in grass nest on sea cliffs in the high arctic. They only overwinter at Race Rocks, feeding on the small herring and krill in the surrounding waters.

Habitat: They are seabirds of the arctic, coastal rocks and rocky headlands. They are usually located on the Pacific coast on North America during winters. At Race Rocks, they often number in the hundreds out on the South West corner of the larger island, as the numbers below show.

Immature Gulls: They are similar to herring gulls, but slightly smaller and with proportionately smaller bill.
Other Members of the Class Aves at Race Rocks.
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams. March 8 2003- Kevin Mingyui Chau