Birds calling

Australian King Parrot

The Strath Creek Landcare group has just released a CD for local distribution titled ‘Bird Calls of the lower King Parrot Valley‘. The CD is intended as a companion to a booklet about birds produced in 2007 and follows the same format as the booklet. Birds, probably more so than any other animals, produce an extraordinary array of sounds and, apart from appreciating their intrinsic beauty, learning the various calls is a valuable means of identifying individual species.
The CD should probably have been titled ‘Bird Vocalisations of …’ since purists distinguish between ‘calls’ and ‘songs’, the former usually being brief, acoustically simple sounds and the latter involving more complex series of varied notes with a recognisable pattern. But it can be a fine distinction and in any case ‘vocalisation’ seems clumsy for a title, so ‘calls’ it is.

Like humans, birds can have slight variations (dialects) between different regions, so we tried wherever possible to record the calls locally.

Birds are unique in possessing an organ called a syrinx. (Unlike us, their larynx serves only to stop food and water entering the windpipe and lungs.) The syrinx or voice-box is a structure at the base of the windpipe where it divides into two bronchial tubes. Rapid contraction of the bird’s lungs forces air through these tubes, and muscles and vibrating membranes within the syrinx create a musical sound. Each tube can be conrolled separately, allowing variations in the sound – one tube may be used mainly for breathing, or both may be used to produce different sounds that either combine or interact. Very rapid shallow breaths coordinated with the call notes allow some birds to sing for lengthy periods without a discernible break. Variations in the structure of the syrinx, as well as the length and diameter of the wind-pipe, account for the great diversity in bird calls/songs.

[For the technically-minded the calls were mostly recorded with a Zoom H4n recorder coupled to a Rode NTG-2 directional microphone.]

Copies of the CD are available free of charge at the Goulburn Broken Catchment Management Authority office in Yea. Click on the audio bars below for a couple of samples of the calls.