The Goulburn Broken Catchment Management Authority is highlighting the importance of tree hollows for wildlife in its 2025 Year of the Tree Hollow community awareness campaign.
This month features three Goulburn Broken catchment owls: the Powerful Owl, Australian Boobook and Australian Owlet-nightjar.
Goulburn Broken CMA Project Officer, Janice Mentiplay-Smith, said The Powerful Owl (Ninox strenua) was Australia’s largest owl.
“In the Goulburn Broken catchment this magnificent top order predator lives in large tracts of forest where it can access territory, nesting hollows and food,” Ms Mentiplay-Smith said.
“A menu favourite is the Brushtail Possum, which also relies on tree hollows.
“Powerful Owls have a slow, double-note ‘whoo-hoo’ call that can be heard across one or more kilometres. Habitat and tree hollow loss is one of the challenges the Powerful Owl is facing.”
Learning a bird’s call is one of the most effective ways to identify them, especially the night-time ones. Visit Powerful Owl Project - BirdLife Australia to hear the Powerful Owl’s call and to learn more about this majestic bird.
The Australian Boobook (Ninox boobook) is the smallest of Australia’s 11 owl species. Its eyes are fixed within bony structures called ‘sclerotic rings’ meaning it cannot move its eyes within the sockets.
“Therefore, it can remain perfectly still and turn its head up to 270 degrees in either direction,” Ms Mentiplay-Smith said.
“Its forward-facing eyes allow for greater depth perception to help it calculate the distance between its talons and next meal.
“Like all owls, the Australian Boobook has excellent night-time vision, however, possibly as an evolutionary trade off, it does not perceive colour very well.”
Ms Mentiplay-Smith said, that with classic “angry bird” eyes, the Australian Owlet-nightjar (Aegotheles cristatus) was one of the Goulburn Broken catchment’s most interesting little nocturnal birds and held the honour of being the only species of owlet-nightjar in Australia.
This owl is insectivorous and hunts at night to dine on a variety of small invertebrates such as moths and spiders and catches its food ‘on the wing’ as well as from the ground.
“Its short, flat bill is surrounded by long, hair-like whiskers called rictal bristles which help this little bird detect and trap prey during its night-time hunt.”
The Australian Owlet-nightjar is hollow dependent, relying on tree hollows and branch cavities in which to nest and safely roost during the day.
The Year of the Tree Hollow is supported by the Victorian Government through the Our Catchments Our Communities stewardship program.
Australian Boobook by Richard Gregson.
Owlet-nightjar by Ruth Ault.
Powerful Owl by Jacob Dedman.