A grackle imported by an emperor
By Jeff Mitton
The contiguous 48 states have suffered the invasion, spread and proliferation of several bird species, most notably pigeons, house sparrows and starlings.
The most recent, highly successful invader is the great-tailed grackle,Quiscalus mexicanus. But this invader has a very different story, beginning with an Aztec emperor.
The Aztecs treasured colorful and exotic birds. The emperors supported extensive zoos and aviaries, and merchants traveled to Panama and the western coast of South America to bring back live birds and feathers. Feathers were used to decorate ceremonial objects and clothing such as headdresses and robes. Taxation extracted from conquered areas often included feathers, live birds and other exotic animals. The demand for feathers and birds inspired breeding facilities for species such as scarlet macaws, which have red, blue, green and yellow feathers.
Emperor Auitzotl, who reigned from 1486 to 1502, acquired an interest in great-tailed grackles, which were native to the coastal lowlands around present-day Veracruz. Birds captured in the coastal lowlands were transported 200 miles to the west and 7,300 feet higher in elevation, where they were introduced to the imperial city of Tenochtitlan in the Mexican highlands. The birds were not confined to aviaries, but were released to live in and around the city. Emperor Auitzotl instructed his people to welcome the birds and to put out food for them. The bird was given the name "teotzanatl," which means "divine or marvelous grackle."
The males are large birds, 17 inches long, with lustrous black feathers glinting iridescent tones of blue and purple. In addition, they have large, long tail feathers that form a keel and earn them the name "great-tailed." Females are 15 inches long, are more brown than black, lack iridescence and have unexceptional tails.
Translocation from sea level to more than 7,000 feet would have certainly introduced great-tailed grackles to a new environment, with respect to both temperature range and plant community. The emperor's order to feed them and make them welcome would have given them some time to evolve the physiological adaptations to a climate with variable temperature and to learn to live as a commensal with mankind in and around human settlements and farms. Perhaps the early years in Tenochtitlan provided great-tailed grackles with the temperature adaptation and behavioral flexibility to launch their invasion of North America.
By the 1880s, great-tailed grackles had spread northward through Mexico and had crossed the Rio Grande River but were restricted to the southernmost portion of Texas. They surged between 1960 and 1980, establishing breeding populations in Utah, Kansas, Colorado and Nebraska. By 2000, they were breeding in South Dakota and Wisconsin and in isolated populations in Idaho and Montana.
The first sighting of great-tailed grackles in Colorado was in 1970, and the first breeding pair was found in the San Luis Valley in 1973. By 2000, they had abandoned their migration and were overwintering in the San Luis Valley, the area around Grand Junction and on the eastern plains.
Great-tailed grackles, pigeons, starlings and house sparrows are all highly successful invaders, thriving in close association with mankind. But pigeons, starlings and house sparrows were all introduced from Europe, where they were already adapted to a temperate climate. Great-tailed grackles were kidnapped from a coastal tropical forest and released in the Mexican highlands. They then invaded all of northern Mexico and most of the 48 contiguous states, adapting to more and more challenging winters as they moved northward.
Jeff Mitton (mitton@colorado.edu) is a professor in the Department of Ecology and Evolutionary Biology at the University of Colorado.
Read more:Jeff Mitton: A grackle imported by an emperor - Boulder Daily Camerahttp://www.dailycamera.com/science-columnists/ci_18052507#ixzz1MF5mJjm5
DailyCamera.com
The contiguous 48 states have suffered the invasion, spread and proliferation of several bird species, most notably pigeons, house sparrows and starlings.
The most recent, highly successful invader is the great-tailed grackle,Quiscalus mexicanus. But this invader has a very different story, beginning with an Aztec emperor.
The Aztecs treasured colorful and exotic birds. The emperors supported extensive zoos and aviaries, and merchants traveled to Panama and the western coast of South America to bring back live birds and feathers. Feathers were used to decorate ceremonial objects and clothing such as headdresses and robes. Taxation extracted from conquered areas often included feathers, live birds and other exotic animals. The demand for feathers and birds inspired breeding facilities for species such as scarlet macaws, which have red, blue, green and yellow feathers.
Emperor Auitzotl, who reigned from 1486 to 1502, acquired an interest in great-tailed grackles, which were native to the coastal lowlands around present-day Veracruz. Birds captured in the coastal lowlands were transported 200 miles to the west and 7,300 feet higher in elevation, where they were introduced to the imperial city of Tenochtitlan in the Mexican highlands. The birds were not confined to aviaries, but were released to live in and around the city. Emperor Auitzotl instructed his people to welcome the birds and to put out food for them. The bird was given the name "teotzanatl," which means "divine or marvelous grackle."
The males are large birds, 17 inches long, with lustrous black feathers glinting iridescent tones of blue and purple. In addition, they have large, long tail feathers that form a keel and earn them the name "great-tailed." Females are 15 inches long, are more brown than black, lack iridescence and have unexceptional tails.
Translocation from sea level to more than 7,000 feet would have certainly introduced great-tailed grackles to a new environment, with respect to both temperature range and plant community. The emperor's order to feed them and make them welcome would have given them some time to evolve the physiological adaptations to a climate with variable temperature and to learn to live as a commensal with mankind in and around human settlements and farms. Perhaps the early years in Tenochtitlan provided great-tailed grackles with the temperature adaptation and behavioral flexibility to launch their invasion of North America.
By the 1880s, great-tailed grackles had spread northward through Mexico and had crossed the Rio Grande River but were restricted to the southernmost portion of Texas. They surged between 1960 and 1980, establishing breeding populations in Utah, Kansas, Colorado and Nebraska. By 2000, they were breeding in South Dakota and Wisconsin and in isolated populations in Idaho and Montana.
The first sighting of great-tailed grackles in Colorado was in 1970, and the first breeding pair was found in the San Luis Valley in 1973. By 2000, they had abandoned their migration and were overwintering in the San Luis Valley, the area around Grand Junction and on the eastern plains.
Great-tailed grackles, pigeons, starlings and house sparrows are all highly successful invaders, thriving in close association with mankind. But pigeons, starlings and house sparrows were all introduced from Europe, where they were already adapted to a temperate climate. Great-tailed grackles were kidnapped from a coastal tropical forest and released in the Mexican highlands. They then invaded all of northern Mexico and most of the 48 contiguous states, adapting to more and more challenging winters as they moved northward.
Jeff Mitton (mitton@colorado.edu) is a professor in the Department of Ecology and Evolutionary Biology at the University of Colorado.
Read more:Jeff Mitton: A grackle imported by an emperor - Boulder Daily Camerahttp://www.dailycamera.com/science-columnists/ci_18052507#ixzz1MF5mJjm5
DailyCamera.com