Macaw parrot bird grooming.
It is either a Scarlet Macao or a Green-winged Macao.
This is one of two Macaw parrot birds that can fly free and are trained to come back to their owner at a voice signal. The birds owner often let them fly around Dolores Park in the afternoon, when it's not too windy. It's amazing to see those beautiful rainbow-colored pet birds fly around and come back to land on their master's shoulder.
Photo taken in Dolores Park (San Francisco)