When in the wild, you have two options for food.  First, you can find and catch your own.  Second, you can find someone else that has already found and caught some food, and you can steal it from them.  The latter is way easier than the former, provided you have the ability to relieve the owner of their meal.  I was walking alongside the water at the locks in Ballard one weekend and a crow was attempting to help a gull lose weight by taking its meal.  What followed was quite some aerial ballet and they twisted and turned with the gull trying to make sure it kept a good hold on its food while maneuvering hard to prevent the crow from taking anything.  The gull was ultimately successful in this case.