The Brood Parasite

The Brood Parasite…sounds like a schlock horror video nasty from the 1980s only available under the counter from your video shop on a dodgy, copied VHS (no Betamax). Of course, it’s a biological term to describe certain species that allow another species to raise their young as their own. For the duped species, this is a real-life horror story.

On the 18th May, 2019, Mrs Sciencebase and I once more visited RSPB Ouse Washes, near Manea, Cambridgeshire, and witnessed one such brood parasite, the European Cuckoo (Cuculus canorus), as it emerged from a reedbed where there were lots of Reed Warblers, Sedge Warblers, and Reed Buntings chattering and calling.

We can only assume this was a female, recently mated having arrived with the male cuckoos from Southern Africa in the last couple of weeks. As every schoolchild knows, the Cuckoo builds no nest, instead, it lays its eggs in the nests of other birds and then abandons them, leaving the hapless warblers to incubate the Cuckoo’s egg alongside their own. When the Cuckoo hatches it will commonly nudge out any warbler eggs in the nest and leave its tiny surrogate parents to run themselves ragged feeding it and raising it as their own.

Neither the surrogates, parasitised in the truest sense of that word nor the imprinted Cuckoo chick is aware that anything is wrong with this scenario…but we do…and it is horrific. I say the adult cuckoos are unaware…but if so, why do they look so guilty?