Tanmay with cuckoo finch

Perfect signatures and perfect forgeries

Tanmay Dixit writes:

I am studying the African cuckoo finch, which as its name suggests behaves like a cuckoo: it lays its eggs in the nests of ‘host’ birds, namely warblers. The warblers have evolved to reject eggs of the cuckoo finch, which has resulted in the cuckoo finch accurately forging the complex patterns (‘signatures’) of their hosts.

Tanmay with a toucan

How should hosts respond? I am trying to determine how they could perfect their signatures, using mathematical and psychophysical approaches, and attempting to work out how logical hosts are in deciding which eggs to reject.

To do this, I spend half of my year in Zambia, pretending to be a parasite by placing eggs in the nests of hosts, measuring their pattern and colour properties, and observing whether those eggs are rejected. Observing time-points within this fascinating arms race, as the cuckoo finch and host each evolve to outwit the other, is a biologist’s delight! 


Click the hyperlinks to discover more about Tanmay’s work with the African Cuckoo and other birds or the Zambia Team.

Test your knowledge with Tanmay’s Bird Brainteaser crossword puzzle.

Have a go at our Cryptic Egg Hunt to see more examples of mimicry in action.

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