|Edgar Percival Chance|
Edgbaston, Birmingham, England
|Other names||Cuckoo Chance|
|Alma mater||Trinity College, Cambridge|
|Known for||Study of the common cuckoo|
Edgar Percival Chance (1881–1955) was a British businessman, ornithologist and oologist who amassed a collection of 25,000 birds' eggs. He is noted for his pioneering studies on the parasitic breeding behaviour of the common cuckoo (Cuculus canorus).
Chance was born at Edgbaston, in the city of Birmingham, the son of Alexander Macomb Chance and Florence Mercer. Chance's fraternal grandmother was Cornelia de Peyster, whose ancestors were Dutch and Huguenot settlers in British North America and Loyalist to the Crown. 
He was educated at Trinity College, Cambridge. He was a wealthy businessman and industrialist who managed the family chemicals business, Chance and Hunt, based in Oldbury, West Midlands, which provided chemicals to Chance Brothers, the famous glassmakers based in Smethwick, Birmingham, between the first and second world wars. He was an egg-collector who became fascinated by cuckoos and made intensive studies of the common cuckoo, in the course of which he wrote two books about the species as well as producing a film. The film – The Cuckoo's Secret – was shot at Pound Green Common in Worcestershire, showing for the first time that female cuckoos lay their eggs directly into the nests of their hosts, rather than laying them on the ground and placing them in the nests with their bills as was previously widely believed. He also achieved a world record for collecting the most eggs – 25 – from a single female cuckoo in the course of one breeding season (1922).
Chance was a member of the British Ornithologists' Union – from which his egg collecting eventually resulted in his expulsion – and served on the Council of the British Oological Association. He named his daughter Cardamine, alluding to the scientific name of the cuckoo flower Cardamine pratensis.
Edgar Chance's elder brother Kenneth Macomb Chance, Sheriff of Warwickshire in 1948 and founder of British Industrial Plastics, was also a keen egg-collector, forming between 1925 and 1938 a complete collection of Warwickshire birds' eggs which is now in the possession of his grandson.
Chance died at his home, age 74, on 24 October 1955.
- 1922 – The Cuckoo's Secret. Sidgwick and Jackson: London.
- 1940 – The Truth About the Cuckoo. Country Life: London.
Among Chance's many articles in the ornithological literature are:
- Chance, Edgar P.; Hann, Harry W. (July 1942). "The European Cuckoo and the Cowbird". Bird Banding. XIII (3): 99–103. doi:10.2307/4509742.
- 1922 – Secrets of Nature: The Cuckoo's Secret. Producer: Edgar Chance. Director of Photography: Oliver Pike. Released by British Instructional Films (BIF). 'The Cuckoo's Secret' is available on the BFI DVD 'Secrets of Nature', released in 2010.
- NHM picture library
- Howard, Joseph Jackson. Visitation of England and Wales, Volume 3. Great Britain, 1895, pages 63,71
- Chance & Hunt
- BFI Screenonline
- Mike Birkhead Associates
- BBC Natural world, 'Cuckoo'
- Davies, Nick (2015). Cuckoo: Cheating by Nature. Bloomsbury. p. 37. ISBN 9781408856567.
- Dixon, Bryony (September 2010). "Secrets of Nature (DVD sleeve notes)". London: BFI: 31.
- "Birdwatcher gave 1922 cuckoo clue". Babbidge, Clare. BBC. 9 January 2009. Retrieved 1 October 2010.
- "The Cuckoo's Secret (1922)". BFI Screenonline. British Film Institute. October 2003. Retrieved 1 October 2010.
- "A Short History of Chance & Hunt". Chance & Hunt. Archived from the original on 12 October 2008. Retrieved 1 October 2010.
- "Cuckoo!". Mike Birkhead Associates. Retrieved 19 October 2015.
- "Manuscript Collection of Edgar Percival Chance (1881–1955) – A Collection Description". NHM collections. Natural History Museum. 2010. Retrieved 1 October 2010.
- "Cuckoo and host eggs, from the collection of ornithologist Edgar Percival Chance". NHM picture library. Natural History Museum. 2008. Retrieved 1 October 2010.
- "Secrets of Nature: The Cuckoo's Secret (1922)". Wild Film History. Retrieved 1 October 2010.