If you think conning or swindling others is something that was invented by the amazingly bright human mind, think again - the cuckoo finch has been doing it for centuries and their con is much more convincing than anything humans have been able to pull, because it entails tricking other birds into raising their chicks!
As you can imagine pulling off a con like this consistently requires some careful planning and a boatload of craftiness - Both that the regal bird with beautiful yellow-brown feathers seems to have in abundance, according to Claire Spottiswoode, a researcher at the University of Cambridge who conducted a study on the crafty creatures in Zambia,Africa and published the findings in the September 24th edition of Nature Communications.
The first step of course involves finding the right 'foster' parent. That role has been played for numerous years by three different birds belonging to the Cisticola species and the tiny Prinia. While these birds are not as good looking as the cuckoo finch their eggs are gorgeous - ranging from blue with small squiggly designs to pinkish-red and even, olive green.
The first step in conning them is laying eggs that are as pretty - Of course the cuckoo finch female can't emulate all of them. So instead, every female bird targets one of the four foster birds, and specializes in laying one particular egg design that is eerily similar. How they manage to do this despite breeding with different males, is a mystery that the researchers have yet to solve.
However, while the eggs look similar they are not the same, which means that if the cuckoo finch drops just one in a nest, chances are that the foster mother will know it's a fraud and toss it out. To avoid that, the parasite bird places multiple eggs, sometimes even more than the ones that are already present in the targeted nest. With so many different looking eggs, the Cistcola or Prinia will not dare toss them out, for fear that they may be killing their own babies! To make things worse, the smart birds deposit eggs in the same nest over and over, so that the poor foster mother thinks having eggs that are slightly different is pretty normal!
If all this is not enough, the parasite chicks hatch two days earlier than their foster siblings. This means that they often chow down all the food that the mother can provide, causing her real babies to die of starvation often, within two days of being born. Scientists are not sure why the host birds simply don't toss out the parasite babies given that don't look anything like their offspring. They speculate that it could be one of two things - Either they just don't realize their mistake or that because of repeated hatchlings they are so used to having unusual looking babies they believe the cuckoo finch chicks belong to them.
So what is a poor host bird to do? Over the years, those that survived have evolved so that their eggs start to look less like the cuckoo finch's. Each female has also started to lay eggs that are slightly different from those of their own species, so that if the crafty parasite bird deposits its blue eggs into a nest which has one with small speckles, they will be spotted and tossed out.
But if you think that has sidetracked the crafty parasite you could not be further from the truth. It merrily evolves along with its host family. Over 30 years ago the cuckoo finch used to lay red eggs. When the host families changed the color to blue so did the parasite. The desperate Prinia have now evolved their egg color to olive and the scientists believe that the cuckoo finch is probably not too far behind!
As to the reason the bird goes through so much trouble to pawn off its offspring? Researchers believe that it is because they do not want to waste the time and energy fostering them when others can do the same job. They would rather spend their energies producing more eggs!
While this study focused on the cuckoo finch researchers say they are not the only parasites around. About 100 species or one percent of known birds do the same and it is also a common practice among insects, as well as, some fish. In fact the cuckoo catfish that is endemic to Lake Tanganyika in Africa, is known to be the ultimate con artist - The eggs that she deposits in another fish's mouth not only hatch there, but also, devour the eggs of the foster fish, all whilst still in the mouth!