Loudmouth Grackles are Moving In By JOE EATON Special to the Planet

Tuesday June 28, 2005

There are no great-tailed grackles in Berkeley yet, but I suspect it’s only a matter of time. They’ve made it at least as far as Hayward, where I saw a quartet—three males and a female—a couple of weeks ago in the marshes north of the San Mateo Bridge. The birds have been nesting at McNabney Marsh near Martinez for at least five years, and there’s been at least one successful breeding attempt in Alameda County. 

It was interesting to watch the other birds at the Hayward Regional Shoreline respond to the newcomers. The female grackle was being pestered unmercifully by the resident barn swallows. One of the males landed near a nesting pair of black-necked stilts and was chased away by the male stilt. The male grackle may have looked enough like a crow, albeit smaller and glossier, to set off the stilt’s nest-predator alarm. That didn’t account for the swallows’ reaction to the brown female, though, and I wondered if she had been messing with their nests. Indeed she had; another birder reported the grackles raiding the swallows’ nests, probably to feed their own young. 

Great-tailed grackles are the largest North American blackbird species (males are 18 inches long, females 15), and arguably the loudest. A territorial male can produce a remarkable range of noises, from soft peeps to what the late ornithologist Alexander Skutch described as “martial and stirring” bugle calls and “indescribably harsh, agonized shouts,” and rustling, crackling sounds that seem more mechanical than vocal. The females are quieter. (In Costa Rica, Skutch’s adopted country, males are called clarineros, “trumpeters;” females are sanates). An alpha male controls a territory in which multiple females build their nests. He’s not always successful in keeping rivals out of his turf, and females often mate with nonterritorial males. Nest construction, incubation, and child care are left to the females. 

I’ll admit to mixed feelings about having this bird as a neighbor. But it’s not an alien, like the Eurasian starling or the house sparrow. Call it an invasive native. As other newcomers--the mockingbird, the hooded oriole, the black skimmer—did, the great-tailed grackle has spread on its own by exploiting manmade environments. At home in marshes and brushlands, the grackle also frequents farms and feedlots. In Phoenix and Tucson, it’s the dominant species in the fast-food-parking-lot niche.  

Until the beginning of the twentieth century, the range of the great-tailed grackle stopped just above the Rio Grande. (Southward, it extended through Central America to the coasts of Venezuela and Peru). Then something triggered one of the most dramatic expansions ever documented for a North American bird. One researcher calculated that grackle breeding range in the US increased by over 5000% between 1880 and 2000.  

The birds moved east along the Texas coast into Louisiana, as far as the swamps of the Atchafalaya Basin. To the north, nesting was recorded in Arkansas in 1976, Missouri in 1979, Iowa in 1983, Minnesota in 1993. The grackle wave rolled through north Texas into the Great Plains, colonizng South Dakota by 1998. Westbound grackles reached New Mexico by 1913, Arizona by 1935, Nevada by 1970. On the average, first nesting occurred 5.8 years after their initial appearance in a new state. 

The Colorado River seems to have slowed the grackles down a little 

But they were nesting on the California side as of 1968, and south of the Salton Sea the following year. From the desert, they began a three-pronged advance through California and now nest as far north as the Bay Area, Sacramento, and Mono Lake. A few have nested in Oregon and Idaho, and stragglers have been reported from British Columbia. 

It seems this bird may have had a prior history in the American southwest. Archeologists excavating the ruins of the Hohokam people in central Arizona, whose irrigation-based civilization had collapsed by the fifteenth century, made an intriguing find: the remains of a single great-tailed grackle. It could have been a stray, but historical records hint that it may have come from Mexico as part of a preColumbian trade in exotic birds. 

However you judge the civilization of the Aztecs (on the one hand, human sacrifice; on the other, chocolate), they were skilled aviculturalists. Their pochteca, a merchant class, brought live birds back to the capital from as far away as Panama, and conquered provinces paid tribute in birds and other wildlife. Aztec elites, from the emperor on down, had personal aviaries in which quetzals, parrots, and other resplendent birds were raised for their plumage. The halls of Moctezuma II contained displays of freshwater birds like scarlet ibis, seabirds, and songbirds, and his retinue included skilled bird hunters and veterinarians.  

According to oral accounts compiled by the Franciscan friar Bernardino de Sahagun after the Spanish conquest of the Aztecs, Moctezuma’s predecessor Auitzotl—“the greatest of Aztec conquerors”, according to historian Felipe Fernández-Armesto-- had a weakness for great-tailed grackles. He had them imported from Huaxtec and Totonac lands in what is now the state of Veracruz, and some may have escaped from the royal aviaries and made themselves at home in the streets of Tenochtitlán. Sahagún recorded that they were called teotzanatl (“divine or marvelous grackle”) and that the emperor’s subjects were forbidden to throw rocks at them. 

Birds were also an export item for the ancient Mexicans. Scarlet macaws were captive-bred at aviaries in the state of Chihuahua and sold to the Pueblo peoples further north. So it’s conceivable that 

the grackle found at the Arizona site could have followed that same trade route to become the prized pet of some Hohokam lord. 

It’s unlikely, according to the ornithologists, that the grackles that colonized California are direct descendants of the birds that had the run of the Aztec capital. Different subspecies are involved, and the ones that moved north originated in northern Mexico. Still, the history of grackle-human interaction speaks well for the great-tailed grackle’s adaptability, the traits that made it such a successful colonizer. Scrounging the plazas of Tenochtitlán, patrolling the burger joints, raiding the swallow smorgasbord: it’s a living.