Hi Mary et al.: Seeing the picture I recalled a similar bird, a partial albino red-winged blackbird, in our collection from S. G. Jewett in 1941. I can send a picture if you like.
Google image search also brings up a few similar looking RWBLs.


Gary Shugart, Slater Museum of Natural History, University of Puget Sound, Tacoma & Vashon Island