Lack was born in London and educated at Gresham's School, Holt, Norfolk, and Magdalene College, Cambridge, where he studied Natural Sciences. He was the oldest of four children of Harry Lambert Lack MD FRCS, who later became President of the British Medical Association. The name 'Lack' is derived from 'Lock'. His father grew up in a farming family from Norfolk and became a leading ear, nose and throat surgeon at the London Hospital. Although his father had some interest in birds as a boy it does not appear that he influenced David's interest. His mother Kathleen was the daughter of Lt. Col. McNeil Rind of the Indian army. Kathleen's father was Scottish and on her mother's side was part Irish, Greek and Georgian.

Until the age of fifteen, Lack lived in a large house in Devonshire Place, London. By the age of nine, he had learnt the names of most birds and had written out an alphabetically arranged life-list. In 1928, with an essay on 'My favourite birds' he was the national winner of the senior prize (a silver medal) in the Public School Essay Competition, organized by the Royal Society for the Protection of Birds.

After Cambridge, he became a schoolmaster at Dartington Hall School, Devonshire until Summer 1938 when he took a year off to study bird behaviour on the Galapagos Islands. He was only in the Galapagos for part of that year, starting August 1938. April to August 1939 was spent at the California Academy of Sciences and at Ernst Mayr's home in New Jersey. He returned home in September 1939, after the outbreak of war.

During World War II Lack served in the British Army working on radar research. After hostilities ended he was made Director of the Edward Grey Institute of Field Ornithology at Oxford University (1945—1973). His wartime experience enabled him to make radar observations of bird migration.

Lack's work in ornithology was almost entirely based on studies of the living bird. He was one of the pioneers of life-history studies in Britain, especially those based on quantitative approaches, when some traditional ornithologists of the time were focussing their studies on morphology and geographic distribution. Lack's major scientific research included work on population biology and density dependent regulation. His work suggested that natural selection favoured clutch sizes that ensured the greatest number of surviving young. This interpretation was however debated by V.C. Wynne-Edwards who suggested that clutch-size was density-independent. This was one of the earliest debates on group selection. Lack's studies were based on nidicolous birds and some recent studies have suggested that this may not hold for other groups such as seabirds.

He wrote numerous papers in ornithological journals, and had a knack of choosing memorable titles: he once claimed to have single-handedly caused the renaming of a group of birds through the submission of a scientific paper, his 1935 publication, "Territory and polygamy in a bishop bird, Euplectes hordeacea hordeacea (Linn.)" in the journal Ibis. Up to that point birds in the genus Euplectes had been referred to simply as bishops, but the journal editor felt that with that form the title might cause misunderstanding.

Darwin's finches

Lack's most famous work is Darwin's Finches, a landmark study whose title linked Darwin's name with the Galapagos group of species and popularised the term "Darwin's finches" in 1961, though the term had been introduced by Percy Lowe in 1936. It is often forgotten that there are two versions of this work, and they differ significantly in their conclusions. The first is a book-length monograph, written after his visit to the Galapagos, but not published until 1945. In it Lack interprets the differences in bill size as species recognition signals, that is, as isolating mechanisms.

The second is the later book in which the differences in bill size are interpreted as adaptations to specific food niches, an interpretation that has since been abundantly confirmed. This change of mind, according to Lack's Preface, came about as a result of his reflections on his own data whilst he was doing war work. The effect of this change in interpretation is to put the emphasis for speciation onto natural selection for appropriate food handling instead of seeing it primarily as a by-product of an isolating mechanism. In this way his work contributed to the modern evolutionary synthesis, in which natural selection came to be seen as the prime mover in evolution, and not random or mutational events. Lack's work laid the foundations for the much more extensive work of Peter Grant and his colleagues. Also, Lack's work feeds into studies of island biogeography which continue the same range of issues presented by the Galapagos fauna on a more varied canvas.

"The person who more than anyone else deserves credit for reviving an interest in the ecological significance of species was David Lack... It is now quite clear that the process of speciation is not completed by the acquisition of isolating mechanisms but requires also the acquisition of adaptations that permit co-existence with potential competitors."

Religious beliefs

Lack became a convert to Anglicanism, which led to his composition, in 1957, of a brief book, Evolutionary theory and Christian belief, on the relationship between Christian faith and evolutionary theory. This book foreshadows, in some ways, the non-overlapping magisteria conception of the relationship between religion and science later popularized by Stephen Jay Gould.

Arthur Cain remarked of him "David Lack was the only religious man I knew at that period who did not allow his religion to dictate his view of natural selection."

Career outline

• 1933—1940: biology master at Dartington Hall School
• 1940: study visit to the Galapagos Islands
• 1940—1945: work on radar development
• 1945—1973: Director of the Edward Grey Institute of Field Ornithology, Oxford.
• 1948: ScD, Magdalene College, Cambridge
• 1963: Fellow of Trinity College, Oxford
• 1972: awarded Darwin Medal of the Royal Society
• 1973: dies at Oxford, 12 March 1973.

• 1951: elected Fellow of the Royal Society
• 1958: receives Godman-Salvin medal of the British Ornithologists' Union
• 1962—1966: President, International Ornithological Congress
• 1964—1965: President, British Ecological Society
• 1972: Awarded the Darwin Medal of the Royal Society

The centenary of Lack's birth, 16 July 2010, is to be marked by a 'David Lack Centenary Symposium', hosted by the Edward Grey Institute. A programme of talks will focus on, and celebrate, the scientific contributions of Lack to ornithology, andthe broader fields of ecology and evolution, and assess the development of these fields in the 21st century.

Books

• Lack, David. 1943. The life of the Robin. Witherby, London.
• Lack, David. 1947. Darwin's Finches. Cambridge University Press (reissued in 1961 by Harper, New York, with a new preface by Lack; reissued in 1983 by Cambridge University Press with an introduction and notes by Laurene M. Ratcliffe and Peter T. Boag). ISBN 0-521-25243-1
• Lack, David. 1950. Robin Redbreast. Oxford. (A new edition of this book, revised and expanded by Lack's son Andrew, was published under the title Redbreast: the Robin in life and literature by SMH Books in 2008.)
• Lack, David. 1954. The natural regulation of animal numbers. Oxford University Press, Oxford.
• Lack, David. 1956. Swifts in a tower. Methuen, London.
• Lack, David. 1957. Evolutionary theory and Christian belief: the unresolved conflict. Methuen, London.
• Lack, David. 1966. Population studies of birds. Oxford University Press, Oxford.
• Lack, David. 1968. Ecological adaptations for breeding in birds. Methuen, London.
• Lack, David. 1971. Ecological isolation in birds. Harvard University Press, Cambridge, Mass. and Blackwell, Oxford.
• Lack, David. 1974. Evolution illustrated by waterfowl. Harper & Row, London.
• Lack, David. 1976. Island biology illustrated by the land birds of Jamaica. University of California Press, Berkeley. ISBN 0-520-03007-9 (posthumously).

Selected papers

• Lack, David. 1940. Evolution of the Galapagos finches. Nature 146:324—327.
• Lack, David. 1942. Ecological features of the bird faunas of British small islands. Journal of Animal Ecology 11:9—36.
• Lack, David. 1945. The Galapagos finches (Geospizinae): a study in variation. Occasional Papers of the California Academy of Sciences 21:i—vii, 1—152.
• Lack, David. 1947-8. The significance of clutch-size. Ibis 89, 302—352; 90, 25—45.
• Lack, David 1949. The significance of reproductive isolation. In Jepsen G, Mayr E and Simpson GG (eds) Genetics, paleontology and evolution. Princeton.
• Lack, David. 1954. The evolution of reproductive rates. In Huxley J, Hardy AC and Ford EB (eds). Evolution as a process. Allen & Unwin, London.
• Lack, David. 1967. Interrelationship in breeding adaptations as shown by marine birds. Proc. XIVth Int. Orn. Congr. Oxford 1966, p3—42.
• Lack, David. 1973. The numbers of species of hummingbirds in the West Indies. Evolution 27:326—337.