Dawn chorus…

It was summer when Debby Ng visited Kathmandu, Nepal LINK. At 0430 hours it was bright. And thanks to the many mosquitoes around, she did not get any sleep that night. So she was awake before the birds. Then she heard the birds calling to welcome the coming of daylight. The song of the Oriental Magpie-robin (Copsychus saularis) was the first to be heard. Then, 25 minutes later, the Red-vented Bulbul (Pycnonotus cafer) joined the chorus (below). “He was with his mate, but she remained quiet all the time. In the distant background were some Red Junglefowl (Gallus gallus), Indian (House) Crow (Corvus splendens) and a sunbird,” wrote Debby.

The early morning bird calls is termed the dawn chorus. The Ornithologist’s Dictionary (Erritzoe et al., 2007) defines the dawn chorus as “bird song at its peak at dawn around sunrise.” According to Staicer et al. (1996), “Some of the most remarkable singing occurs at dawn, especially in temperate zones.”

Whether the chorus heard in the tropics is not comparable to that in the temperate zone, we will leave it to others to decide. It is a pity that we do not have an audio of the Kathmandu’s dawn chorus. We do get spectacular choruses in many Southeast Asian countries, especially near to bird sanctuaries. If there is someone with a clip of an actual dawn chorus, locally or otherwise, please send it over so that we can share it with others.

Coming back to urban Singapore. Just the other morning there was a loud “chok-chok-chok” at around 0620 hours. It was the last night call of the Large-tailed Nightjar (Caprimulgus macrurus), a nocturnal species – a prelude to the dawn chorus. Not a pleasant sound to wake up to, unlike the soon to be heard chorus of the Yellow-vented Bulbuls (Pycnonotus goiavier). These common bulbuls celebrate the coming of another day with their series of gurgling songs, usually starting just before dawn. The chorus was peppered with unidentified calls that sounded like “cheeks” and “chips” and an occasional welcome song of the male Oriental Magpie-robin (Copsychus saularis).

This is the urban dawn chorus, not as spectacular as that heard in rural areas, especially around bird sanctuaries or nature parks.

Ornithologists have been debating on why such pent-up energy is unleashed only at dawn. One explanation is that this is the perfect time to attract females. Others believe that it is too early to forage because of the darkness, and what else to do but to proclaim your territory. Kroodsma (2004) suggests that after a night fraught with danger from predators, the dawn that follows the longest period of inactivity might be time to proclaim “I am still alive” and “This territory is mine.”

Debby Ng
Singapore
April 2013

References:
1. Erritzoe, J., K. Kampp, K. Winker & C. B. Frith, 2007. The ornithologist’s dictionary. Lynx Edicions, Barcelona. 290 pp.
2. Kroodsma, D. E., 2004. Vocal behavior. In: Clark, G. A. Jr., 2004.. Pp. 3.1-3.70 in Podulka, S., Rohrbaugh, R.W. Jr & Bonney, R. (eds.), Handbook of bird biology. The Cornell Lab of Ornithology, Ithaca, NY. Pp. 7.99-7.98.
3. Staicer, C. A., D. A. Spector & A. G. Horn, 1996. The dawn chorus and other diet patterns in acoustic singing. In: Ecology and evolution of acoustic communication in birds, pp. 426-453. (Edited by D. E. Kroodsma & E. H. Miller). Cornell University Press, Ithaca, NY.