An interesting example of nature’s evolution through brood parasitism

I am part of a local birding community group on WhatsApp since 2018 and it has been a very interesting couple of years. I have come across so many people from different walks of life in different parts of my home state settled all over the world with so much knowledge and keeps sharing new information and insights every day.

Yesterday, I came across this unusual picture of a female Asian Koel holding the egg of a crow in it’s beak. The photo was taken by Vijayan Mappat who is from my home state (Kerala) and is settled in another city (Pune). I immediately realized that it’s a rare moment because we will not normally get to see birds holding eggs in their beaks unless they are brood parasites. This is an evolutionary adaptation where such birds lay their eggs in the nests of other birds. Once the female host lays her eggs, the brood parasite bird would sneak in, take one egg, throw it down and lay one egg in that space. Vijayan saw the Koel dropping the egg on to the ground. The eggs of such birds would mimic the color and size of the eggs of the host. Hosts sometimes understand a different egg and push it out of their nests so to offset this loss the parasitic birds would lay their eggs in many nests. Different theories have been put forward to explain this behavior. But I believe they evolved into this behavior primarily as a survival strategy because of possible loss of habitat and/or their nests getting repeatedly destroyed by other birds.

Nature is all about continuous evolution and adaptation for survival and camouflaging is one way animals extensively and effectively use. Most of us would find brood parasitism cruel. But this is nature’s way of ensuring the survival of some species of birds and at the same time controlling the population of the host birds. Nature is a self sustaining system and only a proper understanding of it can ensure the survival of our own species.