These terms come up in an interesting academic article calling for more research into the geographical variation in sounds, which, needless to say, often come from birds. In ‘The silence of biogeography’ biologist Mark Lomolino and two colleagues note that bioacoustics (study of animal vocalisation and sound perception) has expanded into the geography of sound, by looking at how soundscapes – the collection of sounds that characterise a particular landscape – vary from place to place and over time.
Soundscapes matter greatly in my book Where Song Began. In the very first paragraph I mention 19th century claims that Australian birds could not sing, and rather than dismissing this as chauvinism I suggest they have some validity:
“Australia does sound harsher than your average field or forest overseas. Like a person vomiting was how Gould described the call of the little wattlebird, a large honeyeater. The great bowerbird’s hissing is described in one 2001 guide as a cross between tearing paper and violent vomiting.”
I drew a causal link between high levels of bird pollination and harsh calls:
“Far more nectar is available to birds in Australia than on other continents – enough to fight over, and harsh cries assert possession. Australia’s eucalypts and paperbarks (Melaleuca) are the only bird pollinated trees on earth to form vast forests, and wattlebirds and lorikeets are important pollinators of their flowers.”
Strident honeyeater calls can be linked to the soils, since plants on infertile soils often prioritise mobility of pollen over mobility of seeds by investing heavily in flowers, which often include large bird-pollinated flowers, which honeyeaters defend with aggression.
Another point is that birdsong in the Northern Hemisphere is produced in a spring peak when male birds returning from winter migration call to establish (or re-establish) breeding territories. With its milder climate Australia has fewer migrating birds deploying spring song to reassert territorial possession. It has many group-breeding birds which don’t advertise with song and which often have harsh calls.
I am pleased that a recent reviewer in the ornithological journal Emu said my interpretation of Australia’s loud honeyeaters was convincing (and described the book as “remarkable on many levels”).
Lomolino is an advocate of soundscape ecology, but my book doesn’t quite qualify as that, because I had no actual sound research to draw upon, except for one study I mentioned on page 85, about Australian songbirds confronted with an owl, a predator, voicing alarm at a lower pitch than European songbirds.
He draws attention to the Vanishing Soundscapes Project, one goal of which is the Full Spectrum Initiative, to record, ‘as full of a bandwidth as possible, all sounds that are produced by Earth at one location in order to determine what frequency ranges have natural periodicities and what kinds of cross-frequency “triggers” might exist in nature’. Such a study, I am sure, would show Australia to be acoustically exceptional.
Lomolino laments that because of extinctions and the spread of introduced species “we are left with, or have created, soundscapes that are increasingly more homogenized.” Australia is probably bucking this trend, because loud native birds, notably cockatoos, lorikeets and large honeyeaters, are increasing in the urban environments that introduced birds favour. Over the course of my life I have seen noisy miners multiply dramatically in Brisbane, to the detriment of sparrows, which epitomised the soundscape I grew up with, but which I rarely hear today.
Jurisevic, M.A. & L. Sanderson, K.J. (1994) Alarm vocalisations in Australian Birds: Convergent characteristics and phylogenetic differences, Emu, 94: 69-77.
Lomolino, M.V., Pijanowski, B.C. and Gasc, A. The silence of biogeography. Journal of Biogeography 42: 1187–119