In the winter months, the Kolea sports yellowish to white underparts with a primarily yellow body, speckled with brown. As spring nears, however, it undergoes a molt into breeding plumage, gaining greater speckling with the addition of whites, as well as a black face, underside, and wingtips. The black portions are separated from the speckled portions by strong, white barring.
- Kolea are fiercely territorial and in Hawaii, will regularly chase off even larger myna birds upon returning to their territories.
- In the spring, usually near the end of April, Kolea gather in large numbers at traditional flocking sites, before migrating en masse to their breeding grounds in the arctic.