Definition of marsh harrier:
(n) :
A raptor in species Circus aeruginosus, which inhabits swampy ground.
(n) :
Any member of the raptor genus Circus of similar appearance and habit to Circus aeruginosus.
(n) :
A western marsh harrier (Circus aeruginosus)
(n) :
An African marsh harrier (Circus ranivorus)
(n) :
An eastern marsh harrier (Circus spilonotus),
(n) :
A swamp harrier (Circus approximans)