Diseased Bird: Unwell SNBU

Unwell SNBU and companion separated themselves from over-wintering flock (currently varies 100-200 birds) and moved into feeder yard about two weeks ago. Unwell bird shelters, and probably spends nights, in a row of white spruce about 50 feet from feeders. Seen alone since about the 19th. Still present at dusk, Feb.23rd.