HomeGlossary Bird topography Rump The lower back, just above the base of the tail. A pale rump seen in flight is a classic field mark for harriers, wheatears and many sandpipers. Bird topographyRelated termsFull glossary Speculum A bright, often iridescent patch on the secondaries of many ducks. Primary projection How far the primary tips extend beyond the tertials on a perched bird. Culmen The upper ridge of the bill from its tip to where the feathers begin. Tertials The innermost flight feathers, next to the body, which often cover the folded primaries on a perched bird. Mantle The upper back, between the nape and the scapulars. Coverts Small feathers that overlap the bases of the flight and tail feathers, on both upper and under surfaces.
Tertials The innermost flight feathers, next to the body, which often cover the folded primaries on a perched bird.
Coverts Small feathers that overlap the bases of the flight and tail feathers, on both upper and under surfaces.