Peter Valentine | Conservation Officer
Many people will have observed finches building their nest in the base of a raptor’s nest. In such cases it does seem obvious that the protection afforded the tiny finch comes from them being too small to be prey for the raptor, and the raptor being large enough to keep any nest predator away. I recall an early sighting of Zebra Finches (two pairs) building their nests in the base of a Wedge-tailed Eagle nest in the Diamantina National Park in Outback Queensland.
Sometimes smaller species will choose to build their nest in the same tree as a pair of Australian Magpies, again presumably for the strong nest predation protection from the magpie. It’s not a topic well explored but one can find occasional examples across Australia.
My first personal observation of multi-species cluster nesting was on our small property along the upper Bohle River in Townsville in 2010. We had a very large ghost gum, Corymbia dallachiana, growing in an open area.
In 2010, I noticed a pair of Spangled Drongos busily attending the trunk of this large Ghost Gum. At that time the outer bark was flaking, and was in the process of falling off to expose the smooth fresher bark below it. I watched the pair of drongos fluttering up and down the trunk and removing bark pieces.
At first I thought they were simply looking for food – insects perhaps, or geckoes. But they seemed quite obsessive, and over the next two weeks completely cleaned the trunk of any residual bark. At that point they switched their attention to nest-building well up in the upper branches of the tree. I watched the activity and was able to see the nest gradually take shape, and as the structure had a fairly open base I was able to observe progress. I also noted, much to my surprise, a pair of Hornbill Friarbirds was building a nest in the tree at about the same stage of construction.
One day I heard a great deal of calling by the drongos. On approaching the tree I found a large Carpet Python trying to climb the tree trunk.
The python was being relentlessly attacked by both of the Spangled Drongos.
It was also clear it was struggling to find purchase on the now smooth trunk, but it kept trying, lifting its head and upper body well above the ground. The drongos were very aggressive in their attack on the python, a snake about 2.5 metres long (see the photo above). Eventually the snake gave up and slithered off.
For me, the penny dropped – the trunk cleaning was snake-proofing the tree! I observed this behaviour most of the following years and the Spangled Drongos continued to nest in that tree. Since moving to Malanda I have missed this interaction.
Two years ago, near our Malanda home, I noticed a pair of Spangled Drongos setting up their nest in a flame tree (Brachychiton acerifolius). The trunk was naturally smooth, but even so I did observe the birds flying up and down the trunk a couple of times. More significantly, I also observed a nest of a Hornbill Friarbird being built in another branch.
This year (2024) a pair of Spangled Drongos built in the same flame tree, and I made a habit of watching the tree as I drove by each week, often stopping to observe with binoculars. I was quite surprised when I noted first an Australasian Figbird building and occupying a nest in the same tree. Then a pair of Magpie-larks built their mud nest in the same tree. And after a while a pair of Hornbill Friarbirds also built and occupied a nest. There did not seem to be any disputes and all four species could be observed in the nest tree at the same time.
I ended up spending time in Cairns for a while and was not able to record nesting success unfortunately. But what an excellent experience and I look forward to future seasons. I hope that others may perhaps observe nesting drongos and record the results and, especially, whether there are other species sharing the nest tree.