Many of the birds out here have feet and toes that serve multiple purposes. Green Heron are one of them.
Large claws help with grabbing limbs and mud. Their wide toes allow then to balance on large vegetation in swamps.
Above the bird is walking across what looks to be water chestnut plants. All the while looking for prey either on the plants or in the water underneath.
The slightest motion and this bird can strike in an instant. Of course this happens just as my arm gets tired from holding the lens on him for long periods.