Tawny Frogmouths are not related to Owls at all, they have soft feathers, silent flight and are nocturnal but this is their only similarity they have. They have very weak feet and toes and catch their prey with their beak. They are closely related to Nightjars but are there own species shared with Marbled and Papuan Frogmouths.
When they open their eye's it is their way of trying to startle a possible threat, they usually have their eye open slightly ( a slit )
Owlet-nightjars are closely related to Nightjars and Frogmouths but again they are their own species.
Hope i don't sound rude Kev, just want to make clear for our friends overseas.
Not at all Shorty. That's wikipedia for you!