Time totweet

September 4, 2013

HEMA VIJAY

• A.J. Mithra’s sonogram (a visual interpretation of audio waves) defines how birds share space among themselves. The vertical axis charts the frequency of sound waves from bird calls, while the horizontal axis gives the length of the bird song in seconds.(Clockwise from right top) Red whiskered bulbul, Magpie robin, Asian koel (male) and Coppersmith barbetPHOTOS: Gnanaskandan K(Anti-clockwise from left top) White breasted kingfisher, Shikra, Spotted owlet and MynaPHOTOS: A.J. MITHRA

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Offbeat Want to know what time it is? Listen carefully and you might just hear a specificbirdcall that tells you what hour of the day it is

Much before sundials and modern clocks came along people deciphered the time with the help of a bird clock. Birds have their own fixed schedules to sing and tweet, and one can even tell the approximate hour of the day from the specific tweets, which makes for a ‘bird clock’. And since Chennai city has a diverse geographical terrain that includes marshland, estuary, rivers, shrub jungle and a coastline, and a diverse avian population that inhabits it we have a great bird clock in the air. Ever woken up in the middle of your sleep, and heard a bird call that goes coooocucucucu in a rising pitch , almost wrapping an entire octave within its tweet? That would probably be the Asian koel, the first bird singer of the day. Without glancing at the clock, you can assume the time to be sometime between 3 a.m. and daybreak. You may also hear the pre-dawn, drill-like call of the white-breasted kingfisher that takes a rolling accent that ascends aggressively and comes back to the note it started with. Just around day break, mynas join in, as do ravens and crows with their kaa-kaa-kaa-ka.

The two note call of the grey francolin sounds off at around seven in the morning, while the high pitched call of the tiny tailor bird might be heard around 7.30 in the morning. If you hear a rhythmic birdcall that sounds like a smithy’s hammer, it is the coppersmith and it is probably 7 to 8 in the morning. Around this time, you might also hear the high-pitched metallic-sounding call of sunbirds, and the gargling calls of the white-browed bulbul and the red-vented bulbul. And then, have you noticed a repertoire of bird phrases that continue with improvisations for around half-an-hour? That would be the magpie robin that sings around dawn and dusk, but its territorial call is heard at other times too. If you hear a three-note call that sounds continuously for three-five minutes, it would be around midday and the call is that of the oriental skylark, that sings when it is in flight, calling as it gains height. If it is winter, you might catch the call of the Indian pitta known as the ‘ aaru mani kuruvi ’ that sings punctually around 6 a.m. and 6 p.m.

During both the pre-dawn and post-dusk twilight hours, the Indian thicknee sings its harsh rising whistle-like call of two or more syllables. As for those rustic calls heard after sundown, that was from the spotted owlet (a harsh, screechy call that goes chirurr-chirurr-chirurr), Indian eagle owl (a deep resonant woo-hooo) and Indian night jars (a short, sharp song that goes chuk chuk-chuk-chuk). And during its breeding season, the common hawk cuckoo (the brain fever bird) can be heard practically through the night, making its shrill and loud two-note call that seems to say ‘brain fever’. However, sparrows and babblers chatter all through the day. Well…these are observations of different birdwatchers in the city; further studies could establish more accuracy.

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