This is an off the cuff post dealing with some Fox Sparrows I recently observed south of home in Half Moon Bay California. I should start by saying that Fox Sparrows are variable, and they are typically separated into four types which some consider are valid as separate species. The classic red one is the bird of the east and north, there is a dark “Sooty” along the Pacific Coast, an interior mountain form (Slate-colored), and a Oregon-California mountains (Thick-billed). Here on the Cal coast we tend to see only the Sooty. But even these vary, the darkest of the dark looks like this:
Last week this bird was south of town, much paler than a Sooty and showing some reddish tones that were brighter than expected, and much grey on face and neck sides. This could be the crazy thing known as “altivagans” a form that is perhaps a hybrid (intergrade) zone between Red Fox Sparrows and Slate-colored Fox Sparrows.
Then there was this bird last week, a whole lotta rust, slight wing bars and streaks on the back. This one is more clear-cut, it is the westernmost form of the Red Fox Sparrow, the subspecies zaboria. To eastern birders this bird will look too dull, but that is what zaboria can look like based on what I have seen up there in Alaska.
It is neat to see such a jumble of different forms down here in winter, it really puts us here in the Half Moon Bay area in direct connection with the habitats and ecology of Alaska, BC, and who knows maybe northern Alberta for the altivagans type thing.