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.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |