Written By onci on Thursday, October 15, 2009 | 6:11 AM
Owls in Australia (Part I) by Ákos Lumnitzer
In Australia we are very lucky to have eight species of owls. Well, nine if one considers the Christmas Island Hawk Owl (Ninox natalis), but most photographers would probably not travel to that far away locality so I will not be discussing that species. Four Aussie owls are members of the Hawk Owl family Strigidae, and four are from the Tytonidae family. In fact, the Tytonidae family owls were recently amalgamated from six species into four. The ones losing their stand-alone status being the Lesser Sooty Owl (prev. Tyto multipunctata) and the Tasmanian Masked Owl (prev. Tyto castanops) both being included as sub-species of the Sooty Owl (T. tenebricosa) and Masked Owl (T. novaehollandiae) respectively. Nevertheless, leaving the scientific jargon aside, our Aussie owls are incredibly diverse in their habitat preferences as well as prey items and also their breeding cycles. Ninox owls tend to breed at pretty much exactly the same time every year, so much so that one could practically set their calendar by the breeding cycles. Often seeing a male and female Ninox owl roosting close together in early winter is a sure sign of amorous things to come and nesting to take place. Most Aussie owls nest in suitable tree hollows, often 40+ meters above ground; although sometimes much lower. Occasionally, an owl may nest in a cave or even barn, though the vast majority do prefer eucalypt tree hollows for raising their family. Often the same hollow is used as the previous year, but the pair may have a number of preferred nest sites in their territory, which they may rotate from one year to the next. Tytonid owls on the other hand, breed when conditions are best for breeding to occur. Sooty Owls will often breed after generous rain had fallen in their preferred territories, which are rainforests, wet mountain gullies and thick woodland. Barn Owls (Tyto javanica) will often breed when their rodent prey become abundant and soon disperse then die from starvation when their food supply is suddenly exhausted. Barn Owls also often live and breed close-by to Letter-winged Kite (Elanus scriptus), another nocturnal raptor, though a hawk and not an owl.
About the only place you won’t find an owl in Australia is its deserts, although the Southern Boobook may penetrate these areas at times. The roughest, toughest seas of sand are practically devoid of these magnificent raptors. On the other hand, our largest, the Powerful Owl (Ninox strenua) is often seen roosting in big city parks and our smallest, the Southern Boobook (Ninox boobook) is often heard in suburbia as it emits its typical boo-book calls at night in the backyards of city dwellers. We are indeed lucky in Australia to have such an abundance of wildlife right on our very doorsteps.
I suppose, the next question is how do you find an owl? That’s a tough one indeed. An owl can be roosting in your backyard one day and be gone the next without a trace It all begins with learning about the particular species you are after. Powerful Owls like dry sclerophyll forests and are restricted to Australia’s SE regions from SE Queensland into Victoria. These large owls also adapt well to city life. Often, their territories include remnant bush land surrounded by modern built-up areas. Southern Boobooks are the most cosmopolitan of our owls as they are practically found everywhere, but they also like a similar environment as the Powerful Owls. However, different target preys mean that the two species – kind of like the Davids and Goliaths of the Aussie owl world, due to their difference in size – can peacefully coexist. Powerful Owls’ main prey are Ring-tailed Possums and occasionally they will take a smaller Brush-tailed Possum and medium-sized birds as well, though mostly those the birds are asleep. Southern Boobooks take insects and mice as well. Rufous Owls (Ninox rufa) live in tropical Australia in dense rainforests. They are the second largest owl after the Powerful Owl. They feed on birds and mammals. Barking Owls (Ninox connivens) like savannah woodland, but can also inhabit well-forested hills and riverine woodlands throughout the continent, where they take a variety of prey, including medium-sized birds and small mammals mostly within a few hours of dusk or a few hours before dawn. Actually, all members of the genus Ninox generally hunt in low light at dusk or dawn as opposed to in the dark of night. Tytonid owls on the other hand, like to hunt all night as they rely on their hearing far more to locate prey than those of the Ninox genus. Barking Owls have a dog-like bark as their main call and another that sends shivers down the spine of grown men, which is the “screaming woman” call.
Part 2 coming soon!
Posted by onci at 6:11 AM