アカクロサギ Egretta rufescens

An entertaining heron to watch—known for sprinting, jumping, and spinning around in shallow water with its wings held up. Dark morph is more common than white morph. Adults are dark gray with a rusty head and neck. Immatures are paler grayish and rusty overall. In breeding plumage, the pink bill and blue lores can become shockingly bright. White morphs are similar to other egrets, but note behavior, grayish legs, and pink bill base (adults). Found exclusively near the coast, especially on mudflats. Typically uncommon, usually seen singly or in scattered small numbers. Dark morph most easily confused with Little Blue Heron, but Reddish Egret is larger and forages much more actively.