Tuesday, 3 January 2017

Square-tailed Kites nesting – update

Please refer to my previous blog post “Square-tailed Kites nesting” for background to this update.

My visits to the Square-tailed Kites nest have now spanned three months (1st of October to 31st of December 2016). Based on an incubation period of 39-41 days – mainly by the female, and nestling times of 52-60 days given in Debus “Birds of Prey of Australia” (p100) the incubation of the eggs of these kites must have started back in late September. Another timing clue is the progress from white downy chicks at hatching to fledged juveniles at 3 weeks of age. And a further clue – the female remains on the nest with the young almost until they fly at about 9 weeks.

Incubation commences when the first egg is laid. Clutch size is normally 2 to 3 eggs. Given the fledging progress of the two nestlings it seems the second egg was laid about 1 week after the first egg.

On my visit on 20th December the older nestling was fully fledged and the younger nestling was still showing some white down around the face – which again suggests about a 1 week age difference. The size difference between the two siblings may also be due to gender with the older bird being a female and the younger one a male.

Please click on photos to enlarge.

There is at least a one week age difference between the two nestlings – the younger one is still showing white downy feathers.
At this stage, the male is still the sole food provider for them all and seems to come in with food about once every hour. The female stays on the nest to look after the young which importantly involves receiving all incoming food deliveries and then allocating them. All food items I have seen coming in are very small featherless nestlings which are swallowed whole or ripped in two.

The male briefly on the nest for a food delivery. There were very few opportunities for a photo of all four on the nest at once.

The female is doing some nest maintenance – the older nestling has its nictitating eye lid closed – a wise if involuntary move given the proximity of the stick being wielded buy its mother. A fresh stem of eucalypt leaves is also visible – the nest is lined with fresh leaves.

I mostly saw the young being fed whole nestlings which they managed to swallow, so it was odd to see the adult female feeding the now well advanced younger nestling tiny pieces of meat.

On my last visit to the nest on 31st of December we arrived to find the older nestling off the nest – this was the first time I had seen it off the nest. Mum and the younger nestling were on the nest as usual.

A new development – the older nestling off the nest. No doubt it had walked out along the branch from the nest – no flight involved.
It was not long before the older juvenile moved to another branch below the nest – not far but a short flight none the less.

The nestlings were not far off leaving the nest and taking their first flights. Once off the nest I guess they can no longer be referred to as nestlings so juveniles would be a more appropriate term for them. The juvenile now off the nest perched on a branch that afforded some photos reasonably free of obstructions.

Back shot of the juvenile off the nest. They have a rich rufous colour and no - or very little - white about the face and forehead which is very distinctive in mature birds.
This photo has captured the juvenile with the right wing extended – the upper wing feather detail shows well.

In this shot the rich rufous body feathers with fine dark streaks, the feathered legs and talons all show well.

Even as newly fledged juveniles they are a handsome raptor.

The juvenile held both wings out and fanned its tail and held this position for a minute or two. It looked to be sunning its feathers – was this to condition the feathers in some way or perhaps it was vermin control?

At this stage we noticed that the female had left the nest – she slipped away without us seeing her go. This was the first occasion during my observation times that  she was away from the nest. When she appeared again she did not return at first to the nest but perched in a nearby tree. She then did a few slow circuits around the nest tree including one brief stop on the nest. It seemed to me that she was encouraging the juvenile to fly. It soon moved again to another branch in the nest tree and then another branch again, each time moving a little further from the nest.

The juvenile moves again to another branch.

A little later the juvenile moves yet again with encouragement from the adult female.

The juvenile’s sibling was still on the nest and was also getting excited with much wing flapping – however it was not ready to move off the nest at this point.

The young bird on the nest is also excited and flaps its wings as its older sibling is moving from branch to branch nearby in the nest tree.

And then the juvenile made a big move, what was possibly its first flight away from the nest tree to an adjoining tree. It soon moved to another branch on the outside of the tree on the opposite side to the nest tree. From this position the juvenile was now ready to launch out into the open sky above the valley beyond.

It is possible that the juvenile had made previous flights, however I think it is more likely that we were witnessing its first flight away from the nest tree. Its first flying lesson under its mother’s guidance while she was in a nearby tree.

The juvenile has left the nest tree and flown a short distance to an adjoining tree.
So, after 8 visits to the nest over a three-month period I managed by luck to witness one of the young make its first flight away from the nest tree – on the 31st of December the last day of the year - what a rewarding way to end 2016!

It will not be long before the younger bird also leaves the nest. They will stay in the area close to the nest tree for a while yet. The parents will continue to feed them and see them through that critical time of learning to fly and hunt for themselves.

After all this excitement we reluctantly left the site at 5pm. The next time I visit the site, finding the Kites will be harder and will involve searching the trees in the nest area.  Up to the 31st of December it was easy to find them – they were always on the nest.

Square-tailed Kites are a listed “threatened species” in Victoria, in addition, breeding records in Victoria are very rare. To observe progress of a successful breeding event and obtain photos is a rare privilege.

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