Eastern Yellow Wagtail (Motacilla tschutschensis)

This individual was found yesterday by William Legge at Rodeo Lagoon (37.8319843,-122.5287520). Yellow Wagtails seen in California have been assumed to be Eastern Yellow Wagtail (called "Green-headed Wagtail" by Christides et al.) now split from the similar Western Yellow Wagtail (Motacilla flava). Eastern Yellow Wagtail currently has four accepted subspecies in three groups. Birds breeding in Alaska are the nominate race M. t. tschutschensis. The race M. t. simillima breeding in the Bearing Sea is now merged with nominate; thus only M. t. tschutschensis has been recorded in North America. California has 18 previously accepted records but none in the last ten years. Prior records were all in September except for two in late August.

Identification of immatures (formative plumage) such as this has been problematic. Analysis by Bot et al. (2014) suggest that first fall Eastern Yellow Wagtails usually have a monochrome cold gray and white plumage. Such coloration is rare in the western species which is usually more brown and yellow. A long hind claw is also an indicator favoring Eastern Yellow Wagtail. Vocalizations differ with Eastern having a more rasping flight call. Calls need to be recorded and analyzed to confirm. Fortunately a voice recording of this individual was obtained by Mark Stephenson and included in his 17 September eBird report. I briefly heard the bird call one time today.

Digiscoped with Panasonic LX5 | Nikon FS III | 30X fixed | no adapter.