A Great Blue Heron displaying.
Herons puff out their feathers and make a sound to attract a mate (they also do the same after a mate brings sticks and other material to the nest, sometimes both of them together).
Ritch Grissom Memorial Wetlands, Viera, FLA
Canon EOS 7D; EF100-400mm f/4.5-5.6L IS USM at 400mm; 1/1000 sec; f/11; ISO 400