Observations of mobbing and other agonistic responses to the Powerful Owl Ninox strenua

Mobbing is an anti-predator strategy in which prey animals, notably birds and mammals, aggravate a potential predator to either distract or drive them from the vicinity. The Powerful Owl Ninox strenua is a large forest owl endemic to eastern Australia that preys mainly on arboreal mammals and birds. We identified records of 30 species of birds and one mammal known to mob the Powerful Owl from scientific literature and unpublished studies. In our study in southern Sydney, Powerful Owls were most frequently mobbed by Noisy Miners Manorina melanocephala and Pied Currawongs Strepera graculina, followed by Grey Butcherbirds Cracticus torquatus and Australian Magpies Cracticus tibicen. We observed mobbing by three species of bird and one mammal that were not previously recorded as mobbing species, including agonistic responses by a Tawny Frogmouth Podargus strigoides and Common Brushtail Possum Trichosurus vulpecula during the time owls were active.