American Robin, Male Territorial Behavior

This male robin was happily searching for worms and bugs when his "territory" was invaded by another male robin. This is the start of behavior that leads to at least a chase and possibly a birdfight.

 

Notice how he is able to raise the feathers on his head to form almost a jay-like crest ... and he's started puffing out his chest by raising those feathers. He got even more puffed-up, but I couldn't capture that because just then he headed for his rival like a bat-out-of-you-know-where.

Done