In the May 2004 issue of Promerops, Peter Steyn says that it would be interesting if Spotted Eagle Owls (401) were seen predating on frogs.

There are at least three pairs of Spotted Eagle Owls living in and around the Lower Tokai Plantation, and I have had a great deal of fun picking up their pellets. The pellets of the birds that live along the Princesskasteel River have a great number of frog remains in them.

photograph by Ann Koeslag

The urostyle of a frog is unmistakable. It is more or less the equivalent of the sacrum (i.e. the caudal end of the vertebral column) in mammals and birds. It looks like a bow tie with a long stem attached. It would seem that each family of frogs has a uniquely shaped urostyle. If that is true then the owls in Lower Tokai are taking a lot of Brevicipitidae (Rain Frogs) with a few Pipidea (Platannas). Altogether I have found about 40 urostyles in owl pellets over the past 8 months.

Although I haven't seen the owls eating or catching frogs, some of the pellets have been collected from under the owls on their perches, as well as from where they had just raised chicks, so I think it is safe to say that they came from the owls.