02 October 2021

September 2021 Quiz


California. September. 

Age: This is a large four-cycle species. Based on the bill pattern and marked primary coverts (beneath the central greater coverts where a swath of secondaries are missing), we might be correct in assuming this is a subadult, or near adult. The outermost primaries, p8-p10, are yet to grow, as well as a substantial number of secondary feathers. Thus, this bird is completing its prebasic molt. 

Identification: The heavily marked breast with dense horizontal markings, medium gray upperparts, blocky head and relatively small, dark eye nicely match Glaucous-winged Gull. However, the dark, contrasting primaries (out to p7) suggests hybridization. Glaucous-winged Gulls on the Pacific coast of North America commonly hybridize with Herring and Western Gull in two central hybrid zones, in the Cook Inlet region and the Pacific Northwest, respectively. This individual more closely matches a hybrid with Western Gull, and that's what it was identified as (so-called Olympic Gull).