We have, of course, seen European Honey Bees in our garden since we moved in. However, until today we had not seen a hive. This one was discovered by Richard when he was mowing the grass around the house. The hive is hanging beneath the nest of a Red Wattle Bird in a native Australian tree planted by a previous owner. I am yet to work out the species of the tree, but it flowers in late December/early January and is currently covered in buds.
The hive is also fairly close to a flower garden next to the house, as well as a water fountain, so I guess they are establishing for Summer.
The Australian honey industry relies on European Honey Bees, so bee keepers have managed hives, which are not frowned upon. However, wild swarms of European Honey Bees are seen as invasive creatures which can make it difficult for native bees and pollinating insects to survive.
On the plus side, we are planting seedlings in the vegetable garden, so pollinators are welcome in that corner of the property.
All of this leaves me unsure how to respond to the hive. My gut feel is to leave it there, but if it can be problematic for our bush environment, we may need to consider other options. If you have informed advice on this I would be thankful to receive it.
Fifteen Acres 
I don’t know much about bees but I’d expect the swarm to move on, they’ll need some kind of shelter. We’ve had them around our area in hollow tree trunks and branches and they stayed for years. Apiarists are often delighted to get a free swarm but I guess that depends how far they have to travel to collect them.
Thanks, yes, I was wondering about structure. I just assumed they were building something. We will keep an eye on them and see what happens,