We know the story of Oliver’s parents, up until they went missing. We know that Oliver’s mother is at least four years old, and used to live in Brighton. We know that his father was raised at Albert Park Lake, but also spent time in Williamstown and at the Eastern Treatment Plant. We know that the couple were together for at least three months before Oliver and his siblings hatched.
Oliver and his family are wild black swans. So how do we know so much about them?
Since 2006, researchers from the University of Melbourne have been studying the black swans at Albert Park Lake. To tell the swans apart, each is given a metal leg band with a unique code. These metal bands are designed to last a swan’s lifetime, but they are almost impossible to read from a distance – particularly when a swan has its legs underwater. So the swans are also given a specially designed identification collar, allowing anyone to identify a swan without needing to catch it.
Since the project began, more than 700 people have reported sightings of collared swans, using the MySwan website and mobile app. These sightings provide huge amounts of information about the swans’ behaviour and movements. While some swans have remained at Albert Park, others are regularly seen in other waterways around Melbourne, or further afield. Some swans have even crossed the border into New South Wales.
I joined the black swan team two years ago, when I began my PhD. When I first looked for swan nests at Albert Park, I only had a vague idea of what I was looking for. I was almost surprised when I first saw a swan sitting on a neatly-constructed mound of reeds, twigs and grass. The swan’s name, according to his collar, was W43. His partner was J17. They had built their nest on one of the islands, away from foxes, dogs and people. For the next four to five weeks, the pair took turns incubating their eggs, while I watched from the shore.
A volunteer, Rowan, saw the babies first. To the naked eye, they were tiny pale shapes moving at the nest, barely visible. We had to use a spotting scope to be sure we weren’t imagining them. But there, shuffling beneath the two parents, were three tiny, white balls of fluff. As we watched, these three baby swans – or “cygnets” – followed their parents down the bank and into the water. They were probably less than a day old.
The first time our team caught W43 and J17’s cygnets, they were still far too small for leg bands or collars. The smallest cygnet was only 230g – about the weight of a large potato. So instead, we gave them temporary marks on their feet, which would last until they had grown. We also took a small blood sample for DNA. The DNA would be used to find out whether the cygnets were male or female, and whether W43 was their biological father.
Contrary to popular myth, swans don’t necessarily mate with one partner for life. In fact, around 15% of cygnets are not fathered by their mother’s partner – a discovery that was made by examining the DNA of cygnets at Albert Park Lake. Swans will also find a new partner if something happens to their previous partner, and will even sometimes divorce. For example, W43’s ex-partner was still living nearby when he and J17 built their nest.
After the cygnets had been tagged, weighed, and sampled for DNA, the family was released. They swam out into the lake, honking and bobbing their heads together in a display called a “triumph”. Then they preened themselves vigorously. All appeared well.
Three months later, Oliver’s parents were gone.
We – another research student, Izzy, and I – found the three cygnets grazing by the lake’s edge. They were still grey, fluffy and far too young to fly. We walked around the entire lake. W43 and J17 were nowhere to be seen.
What happened? I still don’t know. Five months later, we received a report that W43 was back at Albert Park, but this was never confirmed. J17 was never seen again. She is now presumed dead.
There are many dangers that a cygnet might experience. There are predators, including foxes. There are cars and dogs. But one of the biggest threats to a cygnet is an adult swan. Black swans are less territorial than their European relatives, but will still attack “intruders”, particularly if they have their own cygnets to feed. For an orphaned cygnet, with no protection from parents and no safe “home”, the situation becomes particularly dire. Within a month, two of the three orphaned cygnets had disappeared.
But the last orphan found ways to escape older swan bullies. Down by the sailing club, we witnessed him being chased by a full-grown male swan, who was flapping furiously, neck outstretched. The cygnet swam straight towards the jetty and ducked underneath. There, between the water and the platform, was just enough space for a cygnet his size. The large male, unable to reach him, soon turned away. As we watched, the cygnet slowly poked his head out from his hiding place, checked the coast was clear, and resumed his search for food.
We started to call him Oliver. He became a local favourite. Hassled by swans on the water, Oliver began to spend his time on land. We would often find him eating grass outside the sailing club café, showing no fear of the people nearby. He somehow always looked as though he was eating ravenously, as though it could be his last meal.
The markings on Oliver’s feet told us that he was “Cygnet 8”, the smallest of W43 and J17’s offspring. But these markings would not last forever. So, when he was eight months old, we captured Oliver to give him his first collar. Oliver showed an unusual response to being captured: he did not respond at all. When Izzy grabbed hold of Oliver, he didn’t even flinch. When she picked him up, he appeared to examine his surroundings curiously. When he was released, Oliver stood on the spot for a few minutes, before checking our hands for food.
Oliver, also known as K40 (“Oliver” wouldn’t fit on his collar), became better at behaving like a swan. But he continued to have his quirks. From a distance, we would see a group of swans ambling about, nibbling at grass – and one swan sitting and tearing the grass apart as though his life depended on it. Sure enough, it would be Oliver. We once arrived at Albert Park to find that all the grass had been mown except for one small patch, about two metres wide. At the edge of this patch, there was a person on a ride-on mower, looking tired and impatient. In the middle of patch, there was Oliver, eating ravenously, with no apparent intention of moving.
I haven’t seen Oliver for four months now. He seemed to vanish, exactly one year after his parents did. Maybe he is exploring around Port Phillip Bay, the way his father did at his age. Maybe I just happen to miss him each time I visit Albert Park Lake. Maybe something worse has happened. But wherever he’s gone, and no matter what happens to him, we will know Oliver’s story when we find him – or at least how it began.
You can log your sightings of wild black swans wearing neck collars, and also upload photos, using the MySwan website or MySwan mobile app.
Anne is a PhD candidate at the University of Melbourne, interested in conservation and the evolution of animal behaviour. She is currently researching how streetlights affect sleep in urban birds, including black swans.
You can find her on Twitter at @AnneAulsebrook.
Banner image courtesy of Anne Aulsebrook.