It was one of those winter days without a trace of wind or swell, when the sea becomes a featureless plain that stretches to the horizon. Truly calm conditions make it difficult to spot marine wildlife from the shore. Pelagic birds such as albatross and shearwaters rely on wind assistance for efficient flying and hunting. They depart, or simply sit on the surface and wait for the winds to return.
Contrary to expectation whales are also more difficult to find in such conditions, making little disturbance as they rise to breath. When these conditions occur it is not unusual that the first sign a whale is nearby when you hear their loud exhalation.
I experienced this scenario a week ago in the lull between two winter storms. I saw eight pods within half an hour. The whales would rise, breath, descend and appear a hundred metres further north. It is amazing how a thirty tonne animal can slip so thoroughly out of sight, despite needing to come to the surface at regular intervals.
A week later and the peak of the whale migration had passed. We’d been walking all morning without one of those ‘spouts all around the horizon’ moments that had been common over the previous weeks. From Marley Headland I noticed a small spout. A few moments later it repeated in what looked like the same spot. Thinking that it might be a Southern Right Whale, a slower swimming species than Humpbacks, I sat to wait for it to come closer.
The whale was travelling north at perhaps a third of the normal Humpback speed. My hope that it was a Southern Right Whale evaporated with the sight of a Humpback’s distinctive dorsal fin. At least one smaller whale was accompanying the Humpback. Bottlenose Dolphins ride the bow-waves created by Humpbacks so my first thought was that was a pod of dolphins. As it got closer I could see that the characteristic beak of the dolphins was missing, and finally the penny dropped. It was a Humpback Calf.
Humpback Whale calves are born white underneath and light grey above. The grey quickly darkens to the same dark shades as the adults. This was a light slate grey, which combined with its small size to suggest that it was at most a few days old.
I got a great view of the baby as it passed my viewing position. It looked a little over 3 metres in length. It was swimming strongly, positioned just behind the adult’s snout to take advantage of the slipstream effect.
Humpback’s normally calf in southern Queensland, where the water is warm enough for the thin blubber (insulation) of the newborns. I was thrilled to see the calf in Sydney, but daunted by the knowledge that it faced a long swim through cold waters, predators and shipping before it reached Queensland.
Later that evening a friend posted that the pair passed Kurnell about three hours after we’d seen them. The distance is 12 kilometres, perhaps 14 if they hugged tightly to the coast, which suggested an average speed of around 4 kilometres per hour. At that speed Hervey Bay, the southern Queensland hot spot for Humpbacks, was 17 days day’s (and night’s) swim away.
The following day I found myself with another wildlife puzzle, this time involving an Eastern Reef Egret.
Eastern Reef Egret
Eastern Reef Egrets are a rocky shore specialist, focusing on the wave swept parts of exposed rock platforms. I sidled close, fully expecting the normally twitchy species to depart. This one was less nervous than usual so I found a perch about ten metres away.
The Eastern Reef Egret stood on the boulder, but rather than resting it was gazing intently at the reef below. A moment later it jumped down, lowered its head until the beak was barely ten centimetres above the water then darted forward. A small fish appeared at the tip of the beak and was quickly tossed down the throat. The egret resumed its stalking, caught another fish then hopped back on the boulder. A moment later it repeated the cycle, catching another fish then back up onto the boulder.
My first thought was that it was simply responding to the waves washing across the platform. That wasn’t quite right, as it was on the boulder when the platform was both dry and flooded. There was a pattern in the egret’s behaviour, but it related to the way that the water from several waves was backing up on the rock platform before slowly draining away. The egret’s boulder sat in an area with a gentle slope, which meant that that the draining water would flow in a thin film across the uneven slope. The egret was ‘hunting’ when the water was actively flowing down slope, picking up the small fish that were retreating back to the sea. Once the water had drained there was no point continuing, so it would jump up and wait for the next group of waves to flood the platform. It was a complex and highly efficient way of targeting a concentration of prey.
Neither Humpback Whales nor Eastern Reef Egrets are unusual sightings in Sydney. Even so, every encounter offers the chance to discover something new.
Odds and sods