The middle duck might be a Gadwall.
looks like a couple of juveniles - first summer birds. no other adults were around- these two seemed like they were on their own in the creek
San Diego County, California, US
there was a breeding pair with a nest
The Mallard (/ˈmælɑrd/ 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 and Australia. This duck belongs to the subfamily Anatinae of the waterfowl family Anatidae.