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Problems of identification of camera-trapped tigers
Indian Wildlife - challenges in the new millennium
The greying of India
On the road to extinction
A Tribute to Rumbha - the elephant  
State development project threatens state bird - Sarus
Shahtoosh ban gains momentum worldwide
The road to disaster
Killing nilgais in the name of crop protection
Warring NGO's may spell doom for the tiger
Where have all the sparrows gone?
Cuckoos that fly out of crows' nests
Corbett park woes continue to mount
A question on post mortem examinations in the wild
Is it time to 'cry wolf' again?
Lifting of US sanctions may boost wildlife conservation
Migratory waterfowl may be hit by war in Afghanistan
UP wetlands to provide improved habitat to waterfowl
Anthrax as a potent wildlife killer
Man-elephant conflict takes heavy toll
Demoiselle cranes fly to safety in India
How long lasting are conservation victories
Fake tiger skins : a knotty disguise
Who cares for the wild here anyway?
A tribute to Charger - the long living tiger
Draining of wetlands threatening wildlife
Wildlife management needs rapid response units
Dudhwa loses another tiger
Indian Wildlife Board meets after five years

Hindustan Times, Lucknow | August 29, 2001


Cuckoos that fly out of crows’ nests


When August comes, it is time for the urban birdwatcher to regale himself with the drama of the crow and the koel, and witness the humbling of the wily crow by a more cunning adversary. In most areas that have tall eucalyptus or gulmohar trees, it is an interesting sight to see a few pairs of common crows (Corvus splendens) busily feeding raucous young ones of the koel (Eudynamys scolopacea).

To the discerning eye, the differences in the parents and the chicks are vividly marked as far as their appearances and the sounds are concerned, but these do not seem to matter at all for the crows. To their parenting instinct, it is enough to know that the squawky little fledglings, consistently clamouring for food, came out from their nests and hence are nothing but their own brood. More often than not, such a brood may not contain even a single crow chick because nature ensures that the larger size and early hatching ability of the parasitic bird results in the host loosing its own clutch, and raising only the young of the parasitic bird.

This then, is a classic example of nest and brood parasitism exhibited in some birds. It is a remarkable reproductive strategy in which one species - the brood parasite – does not build its own nest, but chooses to lay its eggs in the nest prepared by another species. It is this host species that hatches the eggs and later raises the brood parasite's young to adulthood.

The hosts of brood parasites do exhibit some initial defense mechanisms against the usurping of their nests. They may resort to either camouflage or concealment of their nests, or else guarding them aggressively by constantly chasing possible intruders from the vicinity of the nest. But ironically, it is this aggressive behaviour of nesting crows that is easily transformed into successful egg-laying by the koel. As the irritated female crow dashes madly after the male koel that has been ceaselessly needling her while she sits in her nest, the female koel quickly slips into the vacated nest and lays her clutch. She may, if she gets the time, push out some of the crow eggs, but her primary concern is to lay her own before the female crow returns. This done, she quietly flits away to leave the nest back in the possession of the rightful owner, returning triumphantly from the chase.

It is obvious that the female crow is not able to distinguish either the koel’s eggs from its own, or notice the change in their numbers after the koel has added her clutch to the nest. This shows that although the crow is universally regarded as a cunning bird it certainly is naïve when it comes to counting chicks before they are hatched. Taking all the eggs in the nest as being their own, both parents continue to hatch them. Later, when the chicks emerge, they too are not recognized as imposters but raised by the crows as their own. Being early hatchers, the koel chicks usually emerge before the crow chicks, and in the process negate any chance for the crow eggs in the nest to hatch. Feeding these ravenous chicks is the only duty that the crows can perform for the next few weeks. Even if a crow chick does manage to hatch, it is usually bullied to starvation by its larger foster sibling. That is the reason why one may not come across a crow pair feeding a joint brood containing both crow and koel chicks. It is probably when the young koels are grown and ready to fly away to an absolutely different tune, that the stumped foster parents realize the goof-up.

One may wonder ceaselessly at the sequence of events that go into this unique natural phenomenon But the cycle of life goes on happily for the crow and the koel, with both species proving to be quite successful breeders, as is evident by their healthy numbers in our midst.

Which is unfortunately what we can not say for too many species anymore....