A: When it is a Tawny Frogmouth!
Often mistaken for an owl, the tawny frogmouth is actually a member of the nightjar family. The bird is named for its large mouth, which it uses to catch insects and small animals. Both male and female tawny frogmouths have gray plumage with occasional black streaks. Owls belong to the order of Strigiformes, while Tawny Frogmouths (Podargus strigoides) are sometimes placed in the order of Coraciiformes which, in Australia, includes kingfishers and kookaburras.
The reasons for the confusion are plain to see. Here is a bird with the same mottled, cryptic pattern as an Owl, with wide eyes, and keeping the same nocturnal habits as many owl species. Further adding to the confusion is that the call of the Southern Boobook Owl is often wrongly attributed to the Tawny Frogmouth. It is for this reason, that the Tawny Frogmouth is sometimes incorrectly referred to as a Morepork, or Mopoke.
It is only with a closer examination that one will see the marked differences between these two orders.
There are other species of Frogmouths and Nightjars that are often confused with owls, but the Tawny Frogmouth is the one most commonly mistaken for an Owl.*
Southern Boobook Owl