Date: 7/15/17 9:00 pm From: Joel Geier <joel.geier...> Subject: [obol] Re: Stymied by a Sparrow
Dave Irons came at this from a different angle than I did (giving more weight to plumage details rather than structure), so it was interesting to see that he arrived at the same conclusion, that this is probably a Savannah Sparrow.
I should also note, the bill is proportionally quite large (in relation to head size) for a Spizella sparrow, but within the range expected for a Savannah Sparrow (though on the large end).
It doesn't look to me like one of the normal Willamette Valley Savannah Sparrows which tend to be more contrasty. It could be an early migrant from one of the more northern or inland populations.
But I'd like to reinforce the suggestion to pay attention to structure, when you're looking at sparrows. I was only partly joking a week or two ago when I suggested that Savannah Sparrows could be a good warm-up exercise for "stint" season. Both shorebirds and sparrows can be very confusing, if you only look at plumage details. Paying attention to the structure of a sparrow can often help to narrow down the options, before you start to consider plumage details.
A caveat is that we're still in the season where some juvenile sparrows are still growing out their tail feathers, so you could see young Chipping Sparrows that don't yet have full-length tails. For those, bill size and shape are better clues. Also as Dave noted, young Chippers tend to be more heavily and more coarsely streaked than the bird in Phil's photos.