New Holland honeyeaters form the Neighbourhood Watch for the community of birds on my street. With rapid tweets they are quick to warn of the menace of the sparrowhawk and it is not only the other honeyeaters who know their call. The fairy-wrens and scarlet robins also seek shelter in the thickly-packed grevilleas out of harm’s way when they hear the alarm call.
My citizen science observations tell me there are two distinct honeyeater alarm calls – soft, short tweets that announce a bird of prey is passing overhead; and a staccato rapid-fire piping that warns of danger, often unseen by the other birds, closer to hand.
I thought I was alone in thinking there was more to the honeyeater’s frantic signals than mere sounds expressed in panic as they flew to safety. Now I learn in a new book on avian behaviour that the language of birds already defined by their songs extends to what is contained in their alarm calls.
My basic understanding of honeyeater communication has so far alerted me to the sight of wedge-tailed eagles flying above my home in the Waterworks Valley and the more rapid tweets have revealed brown goshawks and collared sparrowhawks hiding in my garden’s bottlebrushes, from where these species usually hunt by ambush.
The book, The Bird Way, reveals birds pack an incredible amount of information into their alarm calls – type of predator, perched or in flight, near or far, how fast approaching and how dangerous.
There is also the revelation that predatory birds not classed as raptors also listen to the alarm calls to learn what birds of prey are about, and if they pose a threat to them.
The book, by Jennifer Ackerman, so fully transports the reader into the world of feathered creatures that the difficulties of an aerial life can be felt and not just heard.
For a garden bird, to be in tune with a honeyeater can be a matter of life and death. Their environment is a dangerous place and as Rob Magrath, a behavioural ecologist quoted in the book, says: “Life as a small bird is like being a human in Jurassic Park.”
The two types of honeyeater alarm call that I have discerned overlooks a third one identified by the author. This is a “mobbing” call which summons all the birds in the garden to descend on a predator, in the hope that safety in numbers will drive it away.
This third option, though, does not seem to apply to the goshawk or the sparrowhawk. They are so ferocious and menacing that my garden birds tend to stay hidden.
After reading the book I listened for the mobbing call and I soon heard it. A neighbour’s moggie was in the garden, a cat too fat and too slow to be considered a threat. A mob of birds just taunted it from a safe distance and sent it on its way
The Bird Way; a new look at how birds talk, work, play, parent and think, is published by Scribe, priced $35.