Birds in Science
Prior to revolutionizing the field of biology through his theory of evolution by natural selection, Charles Darwin served as a naturalist aboard the H.M.S. Beagle on its five-year South American expedition between 1831 and 1836. It was during this trip that Darwin directly witnessed the effects of speciation through evolutionary adaptation. The most famous example of this phenomenon is the Finches of the Galapagos Islands. As the Galapagos Islands are geographically isolated from the mainland of South America, the finches on the islands showed distinct differences in the size and shape of their beaks. Darwin theorized that the island finches shared a common ancestor from the mainland and that the changes in their beaks could be explained as adapting to better suit specific sources of food.
While Darwin is credited with recognizing the significance of the speciation of the Galapagos finches, it was John Gould who first identified the bird samples collected on the expedition as distinct species of finches. Gould was already a celebrated ornithologist and artist by 1837 when he was given Darwin’s samples to study. After a few years of research, Gould’s writings and illustrations were published in Part 3 of Zoology of the Voyage of H.M.S. Beagle.
Darwin’s finches have been further studied since his initial observations. In 1938, evolutionary biologist David Lack traveled to the Galapagos to study the birds firsthand and published his findings in his 1947 book Darwin's Finches; an Essay on the General Biological Theory of Evolution. Lack is credited with coining the term “Darwin’s finches,” which continues to be used today as an easily understood reference to evolution through natural selection.
Charles Darwin (1809-1882)
Journal of Researches into the Natural History and Geology of the Countries Visited during the Voyage of H.M.S. Beagle round the World. London: J. Murray, 1860.
Lehigh University Catalog Record: https://asa.lib.lehigh.edu/asa/Record/258161
A version of this text has been digitized and is available through The Internet Archive.
Digitized Version
The canary in the coal mine is a universal idiom for an early warning system. This phrase refers to the practice of coal miners carrying caged canaries with them to monitor for the presence of carbon monoxide gas, the colorless and odorless gas that causes asphyxiation and death. Through his research into respiration, physician J.S. Haldane identified carbon monoxide as a common cause of death in miners and recommended mice and canaries as indicators of the gas. These smaller animals are more susceptible to carbon monoxide poisoning due to their “enormously greater respiratory exchange and circulation rate.” Canaries were first used in coal mines in 1896, a practice that continued until the introduction of electronic gas sensors in the 1980s.
While canaries are no longer used in mining, the concept of sentinel species that can act as early warnings is still prevalent. Other birds, including tree swallows and herring gulls, are still studied as indicators of aquatic and airborne pollution.
J. S. (John Scott) Haldane (1860-1936).
Organism and Environment as Illustrated by the Physiology of Breathing. New Haven: Yale University Press, 1917.
Lehigh University Catalog Record: https://asa.lib.lehigh.edu/Record/126031
A version of this text has been digitized and is available through The Internet Archive.