Bronzed Cowbird, BraeBurn No. 6-7 Bridge, May 26, 2018
The dark bird in the photo above is a Bronzed Cowbird.  I saw this bird three times in the same place before I realized that it might be a new species for the BraeBirds bird count.  Photographing it was tough because it is a dark bird from beak to tail and it was in shadow with a bright background.  It took over 20 photos from various angles before I could confirm its identity.  In the past, I might have called this a Blackbird and moved on, but the very thick bill, flattened head, puffed out neck feathers, and red iris helped me to identify this as a Cowbird.   A year later, I saw it in the same place, on the bridge between holes 6 and 7.
The Bronzed Cowbird is mostly a Central America to Mexico bird that spends only summers in the southernmost United States from Louisiana to the California-Arizona border.
Cowbirds are in the Blackbird-Grackle-Oriole-Meadowlark family, and are famous, or infamous, for being a brood parasite, an organism that relies on others to raise its young.  Cowbirds lay their eggs in the nests of other birds, and then abandon them, leaving the other bird to handle care and feeding.