Just to bring those of you up to speed in case you haven’t read my earlier blog. In early December, a pair of Pacific Black Ducks investigated the nest of a pair of White-Bellied Sea Eagles (WBSE) in an old Ironwood Tree in the forest of the Sydney Olympic Park in Sydney, Australia. On 14 December, a nest cup was excavated in the centre of the sea eagle nest by the ducks. (Note: This is off-season for the sea eagles.). Six days later, ‘Dad’, the male partner of ‘Lady’, to whom the nest belongs, came to the nest for one of his periodic territory checks. The female aptly named ‘Daisy’ by Phyllis Robbins of the WBSE chat group laid her first egg in the nest cup on 5 January 2021.
On the morning of 11 January, Daisy arrives at the nest just after dawn. Before she could lay her egg, vocalizations from other birds in the forest alert her that the sea eagle is about. Indeed, Daisy might have been listening for the male sea eagle because he had come to the nest the previous day. That day she quickly covered the eggs and flew off the nest but stayed in proximity. Dad stayed for about half an hour before leaving and within a few minutes, Daisy returned to lay her sixth egg without interruption. This morning, however, Daisy had not laid her egg when the large sea bird appeared. She stood on the rim of the nest and quacked as Dad flew to the camera tree. She left so abruptly that she did not have time to cover her eggs but, it seems that Dad did not notice her physical presence on the nest or her quacking.
Dad surveyed his territory remaining on the tree that supports the camera for the live stream for about an hour. He might have thought that the bird laying the eggs would return without noticing him and he would find out who this mysterious bird is.
After about an hour and a half, Dad flew to the nest tree to see first hand what was happening. He had noticed the eggs the previous day by rummaging around in the leaves. He even tried to pick one up with his bill but to no avail.
Today the eggs were clearly visible. Look carefully. Daisy has started removing down from her breast to line the nest. This physiological process is called zugunruhe.
Under normal circumstances, Daisy would arrive at dawn to lay her egg. She would do this every day until she finished laying all of the eggs for her clutch. This can vary between 8-13 eggs. After laying her egg, Daisy often remains on the nest for a period of about an hour before departing for the river to forage for the rest of the day. Once all of the eggs are laid, Daisy will begin full incubation, being relieved periodically by her mate. After twenty-eight days, the ducklings will hatch. Then, the following day (after 24 hours), they will take a giant leap of faith and jump off the rim of the nest, a distance of approximately fourteen metres, to the forest floor. Here they will follow their mother to the Parramatta River where they will immediately begin foraging for themselves.
Today, Dad began to curiously inspect the nest with the eggs. For what seemed like an eternity, he would look at the eggs and then look around the immediate environment of the tree. It was actually like he was confused. At one point he tried to pick up one of the eggs but he couldn’t do it. It isn’t that they are heavy; the shape is just awkward for him to handle with his beak. He did not try to move the eggs with his giant talons nor did he attempt to break them. He did toss some of the down around. At one point, it even looked like he might start brooding the eggs. It was a very strange exchange because Dad’s hormones are not thinking about breeding or brooding. He is in the midst of moulting.
The entire morning was very suspenseful. Currawongs and Sulphur-Crested Cockatoos were screeching in the background and at one point, it was thought that Daisy even did a fly by.
And then the oddest thing happened. Very delicately, Dad covered up the eggs at 9:01 am.
If that wasn’t peculiar enough, Dad went up to one of the ‘parent branches’ on the nest tree and stood vigil. More than once, Dad flapped his wings to keep the Currawongs away! Take altogether, these three actions scream out that his intuition is to protect the eggs.
Dad stayed for more than an hour before departing. At the time of this writing, he has returned once again to the nest tree where he is keeping watch over his territory.