Elegant mountain stream specialist, endemic to Java and Sumatra. Typically encountered foraging alongside narrow and fast-moving forest waterways at 600-2000 meters. Dark gray above and white below, with a dark throat and slender white stripe around the forehead. Males have a gray crown, while females have a dark maroon one (difficult to see in poor lighting). Also note bright white rump. White-crowned Forktail is significantly larger, with white wingbars and a larger white forehead patch. Calls loudly, especially when alarmed, giving high thin whistles. Often bobs tail.