This bird landed in a dead top tree by the NE bridge… I was alone. Luckily two others showed up and I got them on the bird for close to 10 minutes, before it took off heading northerly.
These are my ebird remarks:
Tagged as rare for time and place. Sweetwater at 10:55 AM
Evening Grosbeak 1 This was the darkest bird I've ever seen, with mostly slate gray head and gray into the mantle and upper breast, gray shading the yellow of the lower breast and belly (Possibly dirty?) Massive pale finch beak, Bright yellow forehead-eyebrow stripe Secondaries formed the typical white patch, which was also a bit brown tinged. The normally yellow wing coverts were mostly gray. Yellow under tail coverts, were the most normal yellow of the feathering.
Viewed well for 10 minutes with two other people. The woman, Ruth Howie, was a visitor from Aberdeen Scotland, she photographed the bird; Ed Moll is a docent at Tohono Chul Park.
Both saw all the ID points, including looking at a field guide.