Black Cockatoo Reserve

 
Every day presents an opportunity to meet someone or something new, and last Wednesday was one of those days for me. I had an early start and met a Mundaring Shire bushcare officer and some lovely ladies from the local 'Friends of' group at an amazingly beautiful bush remnant near Mundaring: the Black Cockatoo Reserve. The meeting was arranged to tee up some suitable locations to place motion-sensing cameras on nest boxes installed for Black Cockatoos, and here was the perfect place as there are several boxes which have been in place for a number of years.

One nest box shown to me had, according to the Friends group, not had any birds (cockatoos or otherwise!) showing interest in it for some time. I'd experienced this before and suggested this could be because of a possum living inside, which you wouldn't know unless you saw it emerge on dusk. Having my climbing equipment handy, I thought "...there's only one way to find out!", and scaled the tree to get a closer look.

The first thing I noticed was the way this box had been attached to the tree. You can see from this photo that a large amount of chain has been used to secure the top, and been wrapped twice around the box to hold it to the limb. This is a really awful method! Having chain strapped to the box in this fashion not only cuts into the bark over time, damaging the tree's tissue, but it also shortens the lifespan of the nest box. As the limb becomes thicker, the chain tightens on the box and eventually it will crush it completely.
 
This is not something that is anyone's fault, it just presents a valuable learning opportunity. I've changed many nest box installation techniques by trial and error over the last 10 years and sometimes you have to just adapt things as you go.

While it is true that nest boxes are heavy and chain is the most suitable fastener, there is a way to do this without damaging the tree at all. Chain can be secured to one side of the box, passed around a sturdy fork and through some old rubber piping to protect the bark, then fixed back onto the other side securely. The length of chain used should be long enough to let the box 'hang' in position, and this will also allow some space as the tree grows thicker, protecting the tree and giving the box a longer life.

I am a great believer in respect and understanding of our environment, and as intelligent creatures humans have the ability to minimise our impacts in everything we do. I've climbed trees for over 20 years and always maintained the view that while high in the canopy, the tree is looking after me, so the least I can do is 'be nice to it'!

Back to the nest box inspection - as I looked at the top,  I could see that some birds had been near it recently as it had quite a few chew marks on the hollow log entrance:

And peering inside, I realised my prediction was right - there WAS a possum in there! This cute Common Brushtail Possum (Trichosurus vulpecula) seemed very happy for such a spacious sleeping place, and was surprised to be woken up by me. You can see if you look carefully at the below picture that possums have been using this box for a while - there is the skull and several bones of a long-dead possum littering the floor of the nest box. I've found dead possums inside nest boxes before following consecutive days of severe heat (45˚C +), and can think of this being one possible explanation. Alternatively the animal may have died of old age in his sleep, or possibly attacked by feral bees which are known to be a problem for artificial nest boxes. There is no way animals with such brilliant climbing ability could get trapped: you can see the wire mesh ladder covers all 4 sides. Whichever the case, the live possum clearly isn't worried otherwise he wouldn't be in there!

I was so enthralled by Black Cockatoo Reserve that Gill and I decided to return for a stroll around the reserve this morning. This decision proved enormously worthwhile as we were provided with the lucky opportunity to witness some more unusual animal behaviour. We found a pair of Endangered Carnaby's Black Cockatoos (Calypthorhynchus latirostris) in a dense thicket of Bull Banksia, and spent some time sitting quietly in the bush filming their behaviour.

These birds are known to be devourers of the fruits of a variety of native plants, especially Eucalypts and Hakeas. I'm sure many of you have watched a flock of these birds feeding on honkey nuts or clipping the cones from Banksia trees on the coastal plain. However, I've rarely seen cockies seeking out flowers for a taste of sweet nectar, as these bird were doing. I was privileged to sneak within 10m or so of these wonderful creatures and observe them getting a 'sugar fix'. You can see in the below shot how much pollen has rubbed off on this male's face as he probes his bill close to the stalk to reach the nectar. I observed him using his tongue in fine movements on the flower tips to absorb the nectar. A delicate operation for a bird which often uses its beak like a pair of bolt-cutters!

His nearby mate (who has a pale bill, grey eye-ring and larger white cheek patch) was also tucking into the Banksia flowers and looked up nicely for this photo:

A morning filming Endearing, Endemic, Endangered birds is the best way to start a Snday!