In 1910 anthropologist James Mooney undertook the first thorough investigation of the problem. Scholarly estimates of the pre-Columbian population of Northern America have differed by millions of individuals: the lowest credible approximations propose that some 900,000 people lived north of the Rio Grande in 1492, and the highest posit some 18,000,000. North America and Europe circa 1492 The population of Native America More-recent events are considered in the final part of this article, Developments in the late 20th and early 21st centuries. The sections below consider broad trends in Native American history from the late 15th century to the late 20th century. Likewise, Spanish conquistadors were engaged in a fundamentally different kind of colonial enterprise than were their counterparts from France or England. As one would expect, indigenous American farmers living in stratified societies, such as the Natchez, engaged with Europeans differently than did those who relied on hunting and gathering, such as the Apache. Native American history is made additionally complex by the diverse geographic and cultural backgrounds of the peoples involved. Because such documents are extremely rare, those interested in the Native American past also draw information from traditional arts, folk literature, folklore, archaeology, and other sources. The thoughts and perspectives of indigenous individuals, especially those who lived during the 15th through 19th centuries, have survived in written form less often than is optimal for the historian. SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!.Learn about the major environmental problems facing our planet and what can be done about them! Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.Demystified Videos In Demystified, Britannica has all the answers to your burning questions.This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.BirdCast, live migration map date and time (most easily accessible from image file name/s). To cite live migration map graphics, please use the following syntax:ĭokter, A. The BirdCast project was created by grants from the National Science Foundation and supported by additional grants from Leon Levy Foundation. Rose Postdoctoral Fellowship, and Amazon Web Services. Support for this research came from NASA, Edward W. The migration traffic rate indicates the number of birds per hour that fly across a one kilometer line transect on the earth’s surface oriented perpendicular to the direction of movement of the birds.Ĭornell Lab of Ornithology currently produces these maps. the Rockies) have obstructions that restrict radar coverage, providing the appearance of no migration where migration may be occurring.īrighter colors indicates a higher migration traffic rate (MTR) expressed in units birds/km/hour. Note that many radars in mountainous areas (e.g. Green dots represent radar locations for which data are available red dots represent radar locations with no data available. Orange arrows show directions to which birds flew. Areas with lighter colors experienced more intense bird migration. When present, the red line moving east to west represents the timing of local sunset, the yellow line represents the timing of local sunrise. All graphics are relative to the Eastern time zone. Real-time analysis maps show intensities of actual nocturnal bird migration as detected by the US weather surveillance radar network between local sunset to sunrise.
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