I mentioned three species of birds in "The Food-Share" blog which team up and chase Sparrowhawks away from suburban areas:
1: Australian Magpie...37-44 cm
2: Pied Currawong...42-49 cm
3: Magpie-lark, (or Pee Wee)...26-30 cm
As an example of this teamwork, I'll describe one particular event I watched in its entirety.
Firstly, the setting: In front of my house is a huge elm tree. Its most important duty is to provide sleeping quarters when the annual, large crèche of juvenile Starlings arrive.
Each year, they come from the state of Victoria, in the southern end of Australia, and coincide with the ripening of fruit on my 8metre fig tree.
They reach here as dull, plain-looking, first-time migratory travellers, with a couple of 'carers' and they stay until the figs are almost gone, and by which time they've grown their beautiful metallic-coloured feathers.
My tale here though, occured in early spring and includes a number of Common Mynahs (Acridotheres tristis) - an invasive, introduced species, which plays havoc with nests of native birds, removing eggs, and taking over the nests for their own use. This attracts environmental advocates who capture and euthanase them.
The mynahs are 24cm and a perfect size prey for a Collared Sparrowhawk (Accipiter cirrhocephalus), 30-40cm, (in fact I've witnessed a number of "catches").
One afternoon, I heard a commotion outside my house. I followed the piercing alarm calls of Pee Wees, until I was under, and looking up into, the inner branches of the elm tree.
Two Pee Wees I knew to have a nest nearby, (and apparently then unattended), were noisily objecting to the presence of a Sparrowhawk, quite close to them, and standing on a branch beside the limp body of a mynah.
The Sparrowhawk had been interrupted before eating his catch, but something in the world of natural laws, makes the hawks very wary - even afraid - of the smaller Pee Wees. Whether this is to due to the similar colouring of the Magpies, or their piercing vocals, is up for discussion.
I stood there for some minutes, the scene above not changing at all and then, slowly coming from the south, a responding Pee Wee call could be heard. As it grew louder, I stepped out from beneath the tree and saw two more Pee Wees flying towards the drama in progress. And the most amazing thing was, that between them, was a Currawong.
The two smaller birds had brought help!
When the three newcomers entered the tree's foliage, the first Pee Wee pair immediately left, flying back in the direction of their nest. And seeing the arrival of the Currawong, the Sparrowhawk edged away, finding another branch well back, but not quite willing as yet, to leave his catch behind.
The new Pee Wees continued the alarm calls and the Currawong, instead of solely attempting to scare off the predator, instead, spotted the body of the mynah.
Currawongs alone aren't killers, but they are always interested in eating.
At this point, about 20 minutes had passed and as I looked at the Currawong move in on the mynah, with the Sparrowhawk looking on helplessly nearby, there came more calls from the distant skies.
Within just a few more minutes, a battalion of vocal, winged soldiers had arrived. Magpies and Currawongs, accompanied by more Pee Wees, had come en masse.
This time, the Sparrowhawk did decide to forgo his meal, and as fast as he could, left the tree behind and flew north, followed by a very large, noisy protective comradeship.
Within less than two more minutes, peace was again mine.
The parent pair were back at the job of feeding their chick, the Sparrowhawk chase had almost disappeared in the distance, and the only movement in the tree was the Currawong feasting on the mynah. He was in the company of another of his kind, who'd chosen to miss the excitement of the chase in favour of a free meal.