I was fortunate enough to see and get excellent photographs of the Duck MacGillivray's Warbler. I had heard some speculation that the bird was believed to be an adult female. If so, I disagree. Based on multiple images, the region between the eye and bill, including above and especially below the eye is black and there are a smattering of black feathers at the boundary of the gray hood and yellow breast. These features point to the bird being a male which is supported by the richness of the yellow of the underparts. The lack of prominent black at the terminus of the hood and the grayish-white throat suggest that the bird is not a full adult. The tertials and secondaries are fringes with pale buff - suggesting that it may be a bird of the year. However, the greater wing coverts are a little frayed and not edged, but the tips of the tail feathers do have pointed tips which also suggests it's a first year bird. The coloration (underparts and head pattern) seems strong (bold) for (field guide) illustrations of juvenile plumage but overall I believe the bird is a young male.
I will soon add my best pics to the growing collection already posted. Neat bird regardless. It's been a long time since I've seen one.