A Cuckoo in the nest

In 1788 Edward Jenner famously published the first account of the ejection of host eggs and nestlings by the young Cuckoo. Collingwood was unaware of Jenner’s account – his diary shows his own observational skills.

 27 May 1900, Westgate
Today in a hedge sparrow’s nest I had previously found, I discovered a Cuckoo’s egg which hatched in the afternoon. I brought the young imposter home and placed it in a nest of the first mentioned species within our garden wall, thus having it in easy reach for observation. The eggs in the nest in our garden were fresh.

30 May 1900, Westgate

…… The proceedings were of a highly amusing character and while I was watching I could not refrain from a quiet laugh. It seems so incongruous for such a tiny mite, apparently entirely helpless, to be heaving and working away like a navvy and it appears to add to the deceit of the whole business by this underhand work in its foster-mother’s absence. It lay feebly at the bottom of the nest when she visited it, holding a quivering head uplifted for food, but this apparently was the full extent of its power. Not so however, for when all was quiet this deceitful Cuckoo hoisted the egg upon its back, or, to be more correct, worked itself under and with the legs wide apart sidled little by little up the side of the nest keeping the egg in its hollow back by the aid of its wings. To retain its balance on the steep side of the cup of the nest (also helped by the [fact that the] weight of the egg was well back) the bird kept its head hanging down but perhaps this is from weakness. But this small, naked thing, with a transparent stomach, was indeed funny to see, exhibiting what appeared to be such acuteness and concealed strength, but in reality it is only a parasitic bird using its hereditary instinct.’

Edward Jenner’s decription

The little animal, with the assistance of its rump and wings, contrived to get the bird upon its back, and making a lodgement for the burden by elevating its elbows, clambered backwards with it up the side of the nest until it reached the top, where resting for a moment, it threw off its load with a jerk, and quite disengaged it from the nest. It remained in this situation for a short time, feeling about with the extremity of its wings as if to be convinced whether the business was properly executed, and then dropped into the nest again.