White Song Sparrow
This is an example of a mostly white Song Sparrow at SGL 252 in Lycoming County, PA on October 4, 2020. Birds like this — that have some of their normal plumage (but not all) replaced by white — are commonly referred to as "leucistic," while "albino" is reserved for birds that are completely white with red eyes (i.e. completely lacking any pigment), although that's not technically accurate from a genetic perspective (which I'm no expert in, to be clear). It's probably safest to refer to this bird as having "depigmentation."
On this particular bird, it looks like the majority of the body and head feathers are white, with the exception of some of the streaking. The flight feathers appear normally colored.
The identification of this bird was based on a combination of the structure of the bird, the "normal" parts of the plumage, and the call note, which sounded typical of Song Sparrow.
2022 Update
A very similar bird was present in the same spot during May 2022, being seen on May 8 and May 29. The plumage is slightly different than the photos from 2020 show, so either the bird has had additional pigment loss as it molted, or possibly it's a relative or descendant of the original bird.
Singing also helped to solidify the ID, although I was already pretty confident that it was a Song Sparrow for the reasons outlined above.
May 8, 2022
May 29, 2022
Photos © Bobby Brown
