Definition of rock jumper in US English:

rock jumper

noun

  • Any of several South African songbirds of uncertain affinity, now usually treated as two species of the genus Chaetops (family Chaetopidae), the males of which have boldly marked heads and rufous underparts; specifically C. frenatus (which incorporates the former C. aurantius).

Origin

Early 20th century; earliest use found in Arthur Cowell Stark (d. 1899).