Fascinating Facts – Part 2

Most will remember ‘The Ugly Duckling’ by HANS Christian Andersen, the tale of the duck foster family that raised an unattractive youth, only for it to transform into a beautiful swan! In biology, this is an example of ‘brood parasitism’ and perhaps the best-known example is the common cuckoo (Cuculus canorus), the only British bird not to rear its own young. It lays its egg in the nest of another bird, such as the reed warbler (Acrocephalus scirpaceus), which will incubate it and eventually feed an insatiable young cuckoo. (This practice of lazy but intelligent mothers, is actually relatively uncommon in swans, unless breeding in dense colonies or crowded nesting sites, but who am I to spoil a good story?)

Amazingly, while host parents lay a wide variety of egg colours and patterns, each cuckoo has the ability to lay an egg with similar spots and squiggles, so that it looks just like the host eggs! What is particularly upsetting is that a newly hatched cuckoo chick, even while still naked and blind, will push other eggs and other newly hatched chicks right out of the nest! It can then have all the parents’ attention for itself. Lots of host parents are very good at spotting the unwelcome cuckoo egg and will push it out of the family nest, but some don’t seem to notice the freeloader.

Surely this demonstrates the truths of the early chapters of Genesis. The intelligence and ingenuity of the cuckoo shows evidence of God’s design; especially in how these behaviours are encoded in the bird’s DNA. But we also see evidence of the Fall, and the effect of sin on the wider creation, causing the use of selfish and destructive tactics in the struggle for survival. Researching the behaviour of brood parasites caused one journalist, Jesse GREENSPAN, to comment that they ‘are basically born evil’.

Allow me to finish on a happy note and introduce to you the ‘superb fairy wren’ (Malurus cyaneus) from Australia. They teach their embryonic chicks a password by singing to them while they are still inside the egg. When the chicks have hatched, only those that can repeat the password will be fed. Cuckoos are not able to learn the password. I hope you agree that only God could implement this.


‘The Brilliant Ways Parasitic Birds Terrorize Their Victims’ by JESSE GREENSPAN https://www.audubon.org/news/the-brilliant-ways-parasitic-birds-terrorize-their-victims (Accessed 14/02/2023)

‘Fairy wren embryos found able to discern between adult calls’ by Bob Yirka https://phys.org/news/2014-10-fairy-wren-embryos-discern-adult.html (Accessed 14/02/2023)