Cuckoos are master manipulators. After laying a solo egg in the nest of another species, female cuckoos abandon their offspring to the care of others.
When the interloper hatches, it boots out any other eggs or hatchlings present, then tricks its foster parents into feeding it more by imitating a whole nest of chicks. The host birds then raise the chick as their own. It’s a strategy known as brood parasitism, but how do they know to adopt this strategy, when they’re raised without cuckoo role models?
Animal behaviour is influenced by nurture and nature, but in this instance, genetics holds the trump card. It’s thought that multiple genes influence brood parasitism, and that these genes are passed from mother to daughter. So, the genes that influence a female cuckoo’s parenting style (along with her preference for the species whose nest she’s most likely to hijack) will be consistently passed to her offspring.
You could say that cuckoos are ‘born bad,’ or rather that they simply are what they are: beautiful, successful birds with an unusual lifestyle that has been honed through millions of years of evolution.
Read more:
- Where do birds go when they die?
- Can baby birds really imprint on humans?
- Monogamy and mating: The surprising similarities between birds and humans
- How do baby birds breathe inside their eggs?
Asked by: Robert Green, via email
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