Tropical Kingbird (Tyrannus melancholicus) perched on a wire near Whaleship Road at the north end of Bodega Harbor on 30 September 2012. (Thanks to John Kelly and Bryant Bainbridge for letting me know about this bird!)
This is a rare but regular fall vagrant to California, with 1-4 records/year in Sonoma County. The Birds of North America account states that there are ~30 records for California/year (Stouffer and Chesser 1998), but I'm not sure if this has changed during the past decade?
Check out the entire bird from bill tip to tail tip. Note the relatively large, thick bill, gray head with dark face mask, white throat, yellow breast (with olive wash at the top), gray-green back, and brown tail with shallow notch.
Tropical Kingbirds feed by aerial hawking — they look for prey from a perch, fly off to chase and capture it, and either consume it in the air or return with it to the perch. They're primarily interested in large flying insects.
You might be wondering about the name. "Tropical" refers to the distribution of this species. They breed from southeastern Arizona and west Texas to central Argentina. But every fall some individuals disperse northward along the Pacific Coast, as far north as British Columbia. In Sonoma County, there are a few records in September and November, but most sightings occur during October.
Note: Although I'm calling this a Tropical Kingbird, this species is virtually identical to Couch's Kingbird. They're best told apart by voice, and this bird wasn't calling. For birds that show up along the Pacific Coast, The Birds of North America account says, "All positively identified birds have been Tropical Kingbird (Zimmer 1985), but most are probably never conclusively distinguished from Couch’s Kingbird by voice." According to Rare Birds of California (Hamilton, Patten, and Erickson 2007) there is only one accepted record for Couch's Kingbird in California.