first picture is of the two mother ducks, although doesn't look like it here they are beginning to have territorial struggles. The five ducklings of one of them are little and when they wander into the territory of the other family, their mother tries to drive the other family off. Guess they will work it out. Initially they each had a side of the bridge but the little ones have no concept of such boundaries.
The mallard (/ˈmælɑːrd/ or /ˈmælərd/) or wild duck (Anas platyrhynchos) is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Argentina, Chile, the Falkland Islands and South Africa. This duck belongs to the subfamily Anatinae of the waterfowl family Anatidae.