Nature 2016 April

All about cuckoos in the nest and other more sinister happenings

Towards the end of April we can expect the annual arrival of the cuckoo. The first call in these parts is normally heard around the third week. It will be interesting, given the mildness of the winter period, if the first call is heard earlier for a change.

Despite their surreptitious habits until the early 19th century, the polecat was recorded across widespread areas of England and Wales. Polecats are related to the stoat, weasel and the (American) mink, which in the 20th century was released or escaped into the wild from fur farms. Polecats are also the wild species from which the wholly domesticated ferret was bred in southern Europe some 2,000 years ago. Polecats may have arrived in the British Isles from the continent alongside Norman invaders in the 11th century. In fact their name derives from ‘poulet’ (French for chicken). Above all, what distinguishes the polecat from its relatives is its intelligence. This is exemplified by its reputation as a most cunning predator. Though not as agile as a ferret I would not recommend trying the ferret trick involving trousers. Polecats have stronger jaws and sharper incisor teeth!

Their favoured habitat was lowland areas close to water where they found plentiful supplies of waterfowl. Polecats were also attracted to the well-stocked shooting estates in upland areas including those owned by the Rothschilds, who patronised this part of the Chilterns: at Prestwood there is still a hostelry: the Polecat Inn. In fact it was the polecat’s predilection for pheasant, partridge and poultry which led to its persecution by Victorian gamekeepers and farmers and by the late 1900s trapping and poisoning led to its virtual disappearance from Britain, aside from an enclave in north and west Wales.

As is the natural habit of most carnivore predators, such as the fox, stoat and weasel, the polecat will kill or maim as many as possible in one attack, then remove and secret its prey in several safe-havens such as old fox holes or rabbit burrows. When not raiding domesticated premises, polecats hunt voles, hares, amphibians and even eels. The results of successive surveys reveal that polecat numbers have been recovering since the 1950s and with their prestigious reproductive capabilities are rapidly spreading across the country. Having already reached Wiltshire, Hampshire and Oxfordshire, areas where they have not been seen for 100 years, it may already be the case, and if not it may not be long, before they once again return to the Chilterns.

Gone are the days when left-handed people were labelled ‘sinister’ or were forced to learn to write right-handed. If you are one of the estimated ninety or so lefthanders living in the Hilltop Villages the world may even have become a slightly easier place in recent times since ring-pull lids have made traditional right-handed can-openers redundant! In the animal world there remains an evolutionary struggle as to whether it’s left- or right-handedness that affords distinct advantages and disadvantages.

Evidence of any handiness appears to be limited to bipedal animals. Amongst the great apes, generally routine tasks are done with the right hand whilst specialised activities are undertaken by the left. Interestingly, marsupials, such as red and grey kangaroos and wallabies, with their upright stance, are almost exclusively left-handed. This is displayed when grooming, picking their nose and pulling down branches to feed on leaves.

In birds, handedness is restricted to the most advanced and intelligent species that use tools or have prehensile beaks. Certain members of the crow family exclusively use their left foot to hold twigs or fronds whilst they prepare them for use, held in their beaks while they winkle out grubs. Some parrots use their left foot to hold nuts which they crack open with their beaks.

Locally we have one group of animals that display handedness. Snail shells spiral in a particular way to the left or to the right according to the location of their reproductive organs. In this example whole communities of snails will often comprise either all left or all right handedness. This is because to reproduce the snails need to align their shells: not possible if they coiled in the opposite direction.

Edward Jenner became a Fellow of the Royal Society (RS) in February 1789. He is rightly heralded for his pioneering work on the development of the vaccination process. His rigorous experimentation methods involved injecting cowpox from milkmaids, who were said to be immune from the disfiguring disease, into the arm of a young boy who became protected from the smallpox. The discovery, in the following 200 years, led to widespread immunisation programmes and saved the lives of millions across the world. However, regardless of this momentous achievement, Jenner’s name would still have made a mark, though of a more modest kind, and in the field of natural rather than medical history.

From the time of the Ancient Greeks over 2000 years ago the mysterious behaviour of the cuckoo had intrigued philosophers, such as Aristotle, who pondered how the young of the cuckoo ended up in the nest of another bird that fostered it until it fledged. Jenner was the first person to scientifically describe how cuckoo chicks are reared by a surrogate parent. First he established that the relatively brief period in which the adult cuckoo is resident in England was not long enough for it to rear its own young.

His painstakingly detailed observations led to the discovery that it was the newly hatched cuckoo, and not the adult cuckoo, that levers the foster birds’ eggs or chicks from their nest. He went on to devise investigations that led to the discovery that even a newly hatched cuckoo was capable of ejecting foster parent’s offspring and eggs. The irony of this story is that Jenner’s Fellowship of the RS was awarded for his discovery of cuckoo behaviour and not for his pioneering work on vaccination. However, one is left to wonder that if he had not developed a robust scientific approach with his cuckoo research, his subsequent studies on cowpox would have led to him convincing the sceptical medical and political elite of his ideas on immunisation through vaccination.