![]() ![]() Most of the birds we sampled did eat mostly mast, but a subset had chemical compositions that suggest their diet was made up largely of crops like corn that would have been available even as their traditional sources of food grew scarcer. Yet there was also scattered anecdotal evidence that the birds would at times descend on farmers’ fields of corn and wheat. ![]() Past historical research indicated that mast was the birds’ food of choice, as they roamed up and down the great forests of eastern North America searching out patches at the peak in their masting cycle. At the time of their decline and disappearance, no one had the technology to be able to follow and document the birds throughout their full life cycle, including cross-continental migration. Prior to our research, little was known about the diversity (or lack thereof) of their diet. This suggests that an unchecked commercial pigeon industry was likely the more important driver behind the birds’ extinction.Ī passenger pigeon skull collected during archaeological excavations. Our study found that passenger pigeons could live off other foods, including farmers’ crops. Why giant human-sized beavers died out 10,000 years ago This longer-term record of diet lets us see what a bird ate over its entire life, rather than at a single meal or in a single season. Because bones grow and remodel slowly over the course of an animal’s lifetime, their stable isotope composition gives us information about average diet over a period of months or even years. My colleagues and I used stable isotope analysis to study chemical markers in the bones of passenger pigeons found in archaeological deposits dating from 900-1900, in the heart of the birds’ former nesting habitat in Ontario and Québec.Īn animal’s bones can tell us a lot about what ate before it died. So, which was more likely: hunting or habitat destruction? Diet clues The great American ornithologist John James Audubon may have captured popular sentiment when he said, “… nothing but the gradual diminution of our forests can accomplish their decrease as they not infrequently quadruple their numbers yearly, and always at least double it.” After the Civil War, technological advancements, such as the telegraph and expanding rail networks, helped professional hunters, called pigeoners, to locate migrating flocks at their nesting sites and collect birds, young and old, on an industrial scale. ![]() The conflict between these two ideas was already evident in the early 19th century, when the almost ceaseless slaughter of passenger pigeons was well underway. The other theory was that their obliteration was due mainly to humans killing staggering numbers of birds for sport and to feed growing urban populations. One theory was that because the birds mostly ate a highly specialized diet of tree nuts (known as “mast”), such as acorns and beechnuts, they died off when they could no longer find enough food after the forested habitats they devoured were cut down by humans. ![]() The last wild bird was shot in 1901, and Martha, the last captive bird, died on Sept. A male passenger pigeon on display at the Cleveland Museum of Natural History in Ohio. ![]()
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