The recent shocking UN report on the threatened extinction of one million species has focused global attention on the crucial role of biodiversity in the health of the planet. Almost exactly 30 years ago, the first warning sounded that amphibian species were already in potentially catastrophic freefall. Tim Halliday, who has died aged 73, was one of the leading figures in a worldwide initiative to raise the alarm, and to understand the reasons for the decline. The current chief scientist of the Amphibian Survival Alliance, Phil Bishop, called him “the leading champion and ambassador for all things amphibian”.
In 1989 Halliday was one of the prime movers in organising the First World Congress of Herpetology (herpetology is the study of amphibians and reptiles) at the University of Kent, Canterbury. While studying the courtship and mating of British newts in the wild, he had noticed over the years that the numbers in his study ponds had been falling. As participants at the congress compared notes, they realised that the same was happening all over the world. Many of these declines were described as “enigmatic”, because frogs, toads, newts and salamanders were dying in supposedly protected habitats.
Following the congress, Halliday and others set up the Declining Amphibian Populations Task Force, of which he was international director from 1994 until 2006, under the auspices of the International Union for the Conservation of Nature. The key task was to record numbers of individuals of different species in locations all around the world, to collate the population data with environmental information, and to highlight those species under threat of extinction.
Halliday launched a journal, FrogLog, to share the data, and through a programme of small grants sent young biologists all over the world to find amphibians and record how they were doing. The number of known species has almost doubled since the project began, but the data showed that around one in three was at risk of extinction, more than any other kind of animal.
Halliday and his colleagues concluded that amphibians were peculiarly vulnerable because they live both on land and in water. Human activity, leading to habitat loss, pollution and climate change, takes its toll, as does widespread infection by the chytrid fungus. In his darker moments, Halliday described himself as an “extinction biologist” rather than a conservationist, documenting species that would soon no longer exist. He was delighted, however, when Sri Lankan scientists named a new discovery after him: Pseudophilautus hallidayi, or Halliday’s shrub frog. He made a point of going to visit it in its natural habitat, a deep, wooded ravine near Kandy.
Halliday was born in Marlborough, Wiltshire. His father, Jack Halliday, taught biology at Marlborough college, and his mother, Edna (nee Barlow), was a housemistress there. Tim attended the school and his passion for wildlife began with collecting leeches in the neighbouring water meadows, wondering at their astonishing diversity. The school also furnished him with a large, hardbacked book of cartridge paper in which to make biological drawings: thereafter he would combine his skills as a draughtsman with scientific inquiry.
He studied zoology at Oxford University, and pursued a doctorate on the sexual behaviour of newts in the university’s Animal Behaviour Research Group. The group had been founded by the pioneering ethologist Niko Tinbergen, and provided the starting point for the careers of many others including Desmond Morris, Aubrey Manning and Richard Dawkins.
Halliday became known for his summary figure of the smooth newt courtship sequence, reproduced in several textbooks that were beginning to embrace the quantitative approach to behaviour pioneered by the Tinbergen school. In 1977 he was appointed as a lecturer in biology at the Open University, concluding his career there as professor of biology in 2009. He wrote numerous courses on comparative and evolutionary biology and neuroscience, and maintained a busy programme of fundamental research alongside his conservation work.
He served on the council of the Zoological Society of London from 1990 until 1998, and chaired its committee on conservation: he called this his “suit and tie” period, being more usually seen in T-shirt and red Kickers. His public communication role included advising the BBC on David Attenborough’s programmes Life on Earth and Life in Cold Blood, and he published a popular handbook on frogs in 2016.
Just before Christmas 2016 Halliday’s GP, an old friend, diagnosed him with cancer. It turned out to be a rare and fatal lymphoma. In the years that remained to him, Halliday returned with renewed vigour to his work as a wildlife illustrator, raising thousands of pounds for lymphoma research through an exhibition of his paintings of brilliantly coloured amphibians and birds in September 2018.
In 1970 Halliday married Carolyn Wheeler. The daughter of a GP in Marlborough, Carolyn had been the first girl to attend Marlborough college, and had also studied zoology at Oxford – though Halliday had first met her at nursery school. She and their children, Sam, Jo and Alice, survive him, as do two grandchildren.