Starlings are common residents in my city landscape. In appearance they are kaleidoscopic, polychromatic, iridescent, resplendent. In song, they are whistles, chants, murmurs and twitters. Every spring, they find ways to reconfigure urban structures into sanctuaries for their nests -- structures like this corrugated metal framework.
The main diet for wintering robins is fruit-based. Berries like pyracantha, hawthorn, holly, and juniper meet digestive juices in the stomach's proventriculus at the front end, then transport their seeds through the bird's system for deposit and germination later.
I believe this interaction was a territorial display between two Northern Flickers. Their routine was on a continuous loop for about five minutes, performed on utility cables strung across our view of the city.