My Powerful Owls by David Waterhouse
I discovered their nest hollow by pure chance. It was the Noisy Miners that led me to it. In the gully, with the light fading fast, a flock was making a fuss in the gloom. Nothing unusual about that: they often make a racket for no apparent reason. What drew my attention and aroused my suspicion was that some of them were making repeated vertical dives at a hollow in a gnarled Rusty Gum.
Whipping up my binoculars, I trained them on the hollow and immediately saw a round head swivelling from side to side. It belonged to a large bird which glared at me with huge yellow eyes. It was a brooding Powerful Owl.
To say I was pleased was an understatement. I felt elated. Powerful Owls nesting here in Sydney!
After fifty years’ residence in Australia, I had only ever seen the species a half dozen times and all the sightings had involved only a lone adult, perched high in a tree, mostly a day-time roost. I never learned anything about them. They simply sat still and glared down on me from their lofty perches.
This sighting I knew would be different. Unless I scared the bird I could study it. I switched on my torch. The beam now reflected red eyes peering above the large hollow. Immediately I switched off so as not to alarm the bird. There was no need for concern. She appeared to be treating me with indifference and the impudent miners with contempt.
For decades, I had associated these large birds with remote forests in rugged hills, but lately I’d heard of them being present in Sydney suburbia.
A young man in the local pub had told me of a large owl sitting on his back fence and from the description it could only have been a Powerful Owl. I knew of sightings in bush-covered districts not far away, but in our suburb? Surely not!
Then, one morning, as I was walking to the gym, I spotted a dead Ring-tailed Possum on the nature strip just outside where I live. The animal had been decapitated and there were bits of its fur on the grass and in the gutter. Among these were a few feathers. I picked up one to examine it. It had an arrow-head mark on it, as did another two. Could the possum have been a victim of a Powerful Owl?
That morning I phoned the Curator of Birds at the Australian Museum and asked if I could bring in my find for confirmation.
On arrival, Walter Boles, the curator, took one look at the breast feathers and without even examining any of the stuffed specimens in his cabinets, simply said, ”They’re from a Powerful, no doubt about it.”
It came as no surprise whatsoever to him. There had been a steady stream of reports about ’Powerfuls’ in Sydney. They’d even been seen in Hyde Park in the city and the Botanical Gardens.
Walter called the arrowhead feather markings ‘sagittations’ and no other Australian owls have such markings. So now I knew they were in my own backyard at times – or at least, one was. The next question was, do they merely visit the suburbs to take advantage of the abundance of possum prey or do they breed in local bushland patches?
One night, in the early hours when I was lying awake with the bedroom window open, I heard their deep ‘woo hoo’ calls which I was familiar with from sound recordings. They seemed to come from the next street.
A few months later, a member of the local Flora and Fauna Society told me he had seen a juvenile Powerful Owl sitting quietly in a fig tree at the head of the gully close to his home. The next day, I went to see if it was still there: it was in the very spot he had described.
It seemed to be the same size as an adult, but white on the breast with a black mask over the eyes. It did not move, but its primrose eyes followed me as I shifted to get a better view.
Could it be possible that the owlet had been bred locally? The gully was typical of the habitat of the species– wet sclerophyll forest with lots of tall trees, a small creek and a thick understorey. Some of the old trees had hollows too. Yet the bush remnant covered only about three hectares and was surrounded by housing with lots of lights at night and intermittent noise.
I made several attempts to locate breeding adults the next winter but without success. Then, in early July, standing on a slope halfway down the gully, not one but two shapes of large birds flew silently past me in the moonlight. One had a possum dangling from its claws. They were adult Powerful Owls and both perched on the limb of a large Blackbutt with the orb of the moon just above them. They then proceeded to devour their marsupial meal. I must have just missed the male owl calling his mate out of the nest to supply her with food.
I knew the nest couldn’t be far away, but I only had managed to locate it thanks to the miners.
Years ago, I read a book by David Fleay called, Nightwatchmen of Bush and Plain. In it, he describes having to stumble over boulders and fallen trees in remote Victorian forested hills to find Powerful Owls. They were wary and sensitive to disturbance when discovered. In stark contrast, ”mine” were completely habituated to passing humans with barking dogs, bicycle bells and on several occasions, even exploding firecrackers.
Instead of driving for an hour or two, then tramping in difficult country in the dark as David Fleay was obliged to do, I could walk to my study area in a few minutes from my home and drive there in thirty seconds. How much easier could it get? In addition, as house lights were switched on at dusk, the gully was never in pitch darkness, at least in the first hours of the night. Occasionally car headlight beams strobed the darkness so that torch light shone directly on the owls did not perturb them at all. Compared with Fleay, I was on easy street as far as owl study was concerned.
Now I knew where the nest hollow was, I had a focal point on which I could concentrate my owl watching, without having to worry about scaring them.
A phone call from Birdlife Australia made me aware that I was not alone in having located a pair of Powerful Owls nesting in Sydney. Dozens of active nest hollows had been located. The majority were on the North Shore and these were being discovered by amateur naturalists like myself. I was told by the coordinator of the ‘Powerful Owl Project’, David Bain, that he would be grateful if I could ‘keep an eye on them’ to see if they bred successfully, and were able to supply the fledged owlets with sufficient food until they were old enough to leave. The project’s aim was to see how well the birds were adapting to life in the city. This involves gathering information on breeding success, food sources and how they coped with the hazards of urban or suburban life.
A huge advantage in studying owls’ dietary habits in different locations was to be found in the fact that they cast up moistened fur balls which contained the indigestible parts of their prey. Often, whole skulls or jaw-bones of animals were to be found amongst these ‘pellets’ as they are called.
David Bain asked me to look for and preserve pellets in the freezer. I soon became expert at spotting them beneath the two major roost trees the birds habitually used. A workshop was to be held when observers from all over the Sydney area could find out what ‘their’ owls had been preying upon. It wasn’t long before I became aware that the pair in the gully was breeding and I started to regard them as “my owls” as I got to know them and their ways in detail.
As my observations accumulated little by little, I discovered a great deal about both adults and youngsters. I was lucky enough to have been on the spot to witness the first flight of the second owlet from its nest hole – which was a mere twelve metres or so from the ground. This was far lower than the nest hollows Fleay wrote about in his Mountain Ash forests.
The two owlets were fed by the adults, on both Ring-tailed and Brush-tailed Possums, kept under talons all day from the previous night’s hunting. That is, if the owl had had a successful foray. The adults must have taken over two hundred possums in a year – perhaps almost three hundred.
I learned that it takes just over an hour for a family of four to demolish a possum carcass. The tail was left until last and usually given to one of the young to gulp down.
One night, during a thunderstorm, the sight of four large owls devouring a hapless young Ring-tailed Possum presented a ghoulish image, but on other nights, the impression was a more charming picture of a strongly bonded family sharing a meal in perfect harmony.
The young owls were dependent on their parents for food over many weeks and as they grew and acquired adult plumage, I was curious to observe as best I could, how they make the apparent quantum leap from being spoon-fed to catching their own prey. I found that part of the answer involved play whereby the young, left to their own devices when the parents left to hunt, would crash into sprays of eucalypt foliage, sometimes upside down and break off whole pieces. They would do the same with long ribbons of bark. They would also spot beetles and other insects and grabbed them to eat. It was only a few beakfuls but it no doubt helped. The pellets should yield more information as the adults eventually left the youngsters to fend for themselves.
The night I saw a youngster spot a Ring-tailed Possum from a hundred metres away and succeed in catching it, I knew that at last a major barrier in their lives had been broken. The prey was not shared, so the other youngster must have had its success too, perhaps when I was asleep in bed.
As the nights passed, I became a familiar figure to the evening strollers down the gully’s walking track. Some walkers and their dogs ignored me, others glanced up- ward, following my torch beam, a few stopped to ask what I was looking at. Gradually, I morphed from being an eccentric loner standing around on a track to your local friendly eco-tourist guide. Not one of those who stopped to inquire had ever heard of the Powerful Owl, let alone seen one. Some shrugged and moved on but a few showed interest and came back to ask how ‘my owls’ were. Three or four became intrigued and turned up with cameras to photograph them. It felt strange to hear a voice in the darkness on a cold winter’s night say, ”Is that you, the Owl Man?” and then someone present snapshots of two owlets sitting side by side on a branch.
On no occasion did I reveal the nest hollow to passers-by, as I thought it better for the owls, were they to nest repeatedly each winter, if their breeding place was kept secret.
I believe I contributed in a minor way to creating a little more neighbourhood interest in local wildlife. I hope I made people aware that they were privileged to have an impressive nocturnal predator in their midst, adapting very successfully to a suburban life.