Of the other jaegers, this one is the largest and most barrel-chested, looking like a bulky gull. The distinctive extended spoon-shaped middle tail feathers of breeding adults set them apart. Observe the upperparts that are blackish-brown in color, the untidy black cap that reaches below the bill, and the large white flash on the upper and inside of the outerwing. Although the mature dark morph is completely blackish-brown, it still displays white flashes on its wings. Though they vary, immature birds typically have prominent black-and-white bars on their underwing and undertail coverts and are barred with brown above. has more white shafts on six to eight of the outer wing feathers than other jaegers, and the underwing usually has a more noticeable white flash. Also, compared to other jaegers, Bill is thicker.