There was concern that siblicide was occurring on the White-Bellied Sea Eagle nest in Sydney’s Olympic Park. It is time to put those fears aside. Prey delivery has become regularized and the two are fed regularly, growing, and are becoming curious about what is happening outside the nest.
The White-Bellied Sea Eagles are Australia’s second largest bird of prey. They have a wing span of 1.8-2.2 metres or 6-7 feet. They weigh up to 4.2 kg or 9 lbs. The female is larger and weighs more than the male. This is known as reverse sex size dimorphism. The adults on the Sydney Olympic Park Ironbark Tree are Lady and Dad. There have been a succession of breeding couples using this tree nest for decades.
In 2021, WBSE 27 hatched on 29 July at 4:57 and WBSE 28 hatched 31 July at 5:48 pm. Just to remind you how tiny they were here are two images in those first few days.
In the first image WBSE 27 was not quite 24 hours old.
In this one, WBSE is not quite 24 hours old and WBSE 27 is almost 48 hours old. You can clearly see the egg tooth, the white piece on the tip of the beak that helps them break through the hard egg shell.
Now look at the two of them. WBSE 27 is on the right with WBSE 28 on the left. You can see how 48 hours difference in age impacts the growth of the juvenile feathers.
In terms of the development, we are entering weeks 5 and 6. By week 5, the chicks will still have their white down. Pin feathers will appear on the shoulders, the back and the wing tips. If you look at the image above you can see these dark feathers coming in on each of the chicks. They should be standing on both feet, checking out the nest, and trying to pick up food. They may start to flap their wings. As we get to week 6, more and more of the dark feathers will begin to show all over the chick’s body. They will preen a considerable amount of time per day. They will now do more wing flapping and standing on both of their feet without the aid of the wings. They will continue efforts at self-feeding (if allowed, Lady does love to feed them!).
Looking forward to developments during week 7, the chicks will do a lot more preening as the dark brown juvenile feathers will continue to grow over their entire bodies. It has to be really itchy – those feathers coming in. Their tail will become noticeable. When they sit they may spread their wings. You may see them begin mantling. They will become more steady on their feet. One notable change is the chick’s interest in grapsing twigs and food with their feet. They should continue to work on self-feeding but this, of course, depends on whether or not prey is left on the nest for them to practice.
WBSE 27 is standing nicely on his feet. WBSE 28 still has a crop from an earlier feeding. You can really see how many wing feathers are coming in. Just look at that little tail developing.
It looks like 28 has a bit of a food coma. 27 is busy looking at what is happening outside the nest.
WBSE continues to work on its balance. Notice how it is holding out its wings for balance. Often the birds will use the tip of the win to keep them steady on their feet. By the end of the 6th week, they should be standing without using the wings. WBSE 28 is working hard to do this.
WBSE is also curious as to what the adult is doing up on the branch. Notice how 28 is sitting with its wings loose to the sides. Sometimes I find that the chicks on the nest are actually ahead of the development scales for that week.
Lady has come a long way in her parenting skills. Both chicks wait their turn to be fed. She will give 28 a few bites and then 27 and then back to 28. This method has given the chicks food security and reduced the pecking of 28 by 27.
Lady always looks like she is smiling to me.
Here is the link to the Sydney Sea Eagle Cam.
Thank you so much for joining me. I know that there are so many people who love these little eagles and I wanted to reassure all that the nest is very calm and peaceful and the chicks are developing normally. Take care everyone. Stay safe.
Thank you to the Sea Eagle Cam@ Birdlife Australia Discovery Centre for their streaming cam where I took my screen shots.