THE folk who live on the mountain at Fern Tree pride themselves on being a little different from the rest of the denizens of Hobart.
They are tougher, hardier and their closeness to the whims and moods of nature ensures they band together in times of adversity, watch out for each other when blizzards or bushfire threaten.
They all have a story to tell, and tell it frequently and loudly.
I’m not talking about the human residents of Fern Tree, although much of what I have written so far could apply to them.
I refer to the birds, and the clans within species that choose life in the forests of the mountain, to a more comfortable one closer to the ocean.
I’ve been making a study of birdsong this summer and it reaffirms the view that birds develop regional accents and dialects, which can be very different to corresponding populations just a few kilometres away.
One of the greatest songsters of the Tasmanian bush, the grey shrike-thrush, is a case in point.
We all know the loud “jo-wittee” song of the shrike-thrush but, to my ear, it sounds far more resonant when sung by members of the species who choose the wet forests of the mountain as their own. The song also seems to have a more elaborate build-up before reaching the “jo-wittee” phrase, a melodious chuckle that could almost come from a yellow-throated honeyeater singing high in the trees.
Shrike-thrushes are birds with attitude as well as accents. They are aggressive and pushy in spring and summer when they go in search of nests to prey on eggs and young, and I must say they are not my favourites. But they make a good subject for birdsong study, simply because they are common in evenHobart’s more densely populated suburbs, and sing all the time.
Birds are not born to sing, as was previously believed, but are merely given the vocal tools to sing in a certain way, explaining why birds of various families make similar sounds, as with the “caw” of crows.
Fifty per cent of a bird’s song is actually learned from its parents, and this opens the way for variation.
All this was explained to me once by birdsong expert David Steward, when he visited Tasmania to compile a CD of our bird songs, “Birds Song of Australia –Tasmania”. I soon learned from his recordings the butcherbirds of mainland Australia sang a different song to the “Derwent Jackass”, as it is know here.
My amateur research into birdsong might not offer any shattering scientific theories, but I have learned much to aid my own bird identification. I’ve learned that, as well as listening to musical notes, the phrasing and rhythm of sings is important. The pink, flame and scarlet robins, and satin flycatcher for instance, sing in rhythmic bursts with silence in between. And brush and common bronze-wing pigeons can be told apart because the former issues a booming one-note call precisely at one-second intervals, and the latter takes a three or four-second pause.
Away from the bush, much recent scientific research has concerned urban birds and how their songs are being influenced by cities.
It has been found that urban birds worldwide sing, if not louder, but at a different pitch to compete with the noise from aircraft and traffic. In Australia, it’s been found that urban silvereyes have developed such different habits and songs, that soon they might be considered a separate species.
Different factors, of course, influence the grey shrike-thrushes of Fern Tree, possibly harsher conditions and thicker forest that needs a stronger, more robust song to penetrate cold, still air and thicker vegetation.
But, who knows, a Fern Tree species of shrike-thrush could be developing. The independent, resilient human residents of the mountain would love that… a bird to call their own.