Early during a gray morning at Lake Merritt in Downtown Oakland, this Crow is making its presence known to all around him.  Crows are very intelligent -- like most birds.  They enjoy fighting with other birds larger than themselves if such birds dare invade their territory.  Such attacks are not limited to raptors, but to their larger cousins, the Ravens.

More than anything, Crows love to play.  Their fighting with other birds is play.  Their cawing here and there goes beyond defining their territory.  Like a lot of people, they just love calling attention to themselves.  And they love toys.  Nuts, bolts, nails, bottle caps, etc., are all toys for their amusement.