Blackbirds (not the little thrush found in England, but the New World family of Orioles type of Blackbird) are notorious for being sociable, just like warblers. On migration they do congregate, but usually numbers like this are fairly unusual. The near deafening sound of blackbird calls was just an invitation to check through them. The flock was primarily Brewer's and Red-winged, but if I was ever to see a vagrant blackbird here was the place, and I figured at least I'd get a Tricoloured or two. Almost immediately I had a Yellow-headed Blackbird fly right past me, a rare bird for southern California. After some extensive chasing I found it (it seemed to be an immature male) again with a second female-type* bird.
*Female-type referring to a dull plumage that females show; often juveniles and immatures show similar dull plumage (even colourful males) and usually it is near impossible to distinguish adult females from immature males or females.
I found a Lincoln's Sparrow sneaking around the children's playground area. Soon enough I had some pretty good candidates for the uncommon Tricoloured Blackbird too. Tricolours are like small Red-wings. The best way to tell them apart is by the colour band on the epaulette of the wing (if it shows yellow or orange is definitely a Red-winged, however in Tricoloured it is usually white).
|Though some fall Red-winged can show some diluted colouration it seemed very likely that the white|
bar on the scapular/epaulette was legitimate.
Only two other rare blackbirds remained (not including Orioles, but Orioles don't socialize with the "ground" blackbirds) and those two were the Rusty Blackbird (a scarce accidental) and the sparrow-like Bobolink (scarce but not as rare as Rusty) however I could not find any that resembled these two. Rusty males are painful to identify as they are very similar to Brewer's with a slightly less intensive sheen on their feathers, so who knows, there may have been one around.