Free birds.

WHEN 5-year-old Hannah heard the screeching and yelled "Parrots!" the adults thought it was just a child's wishful fantasy. But on the third pass by a flock of about 30 green birds, everyone was convinced.

Incredulous, but convinced.

In fact, L.A. is home to a number of flocks of feral parrots, according to Kimball Garrett, ornithology collections manager at the Natural History Museum of L.A. County.

As many as 11 species, most indigenous to Mexico and South America, have established themselves in the Los Angeles area, he said, setting up in Malibu, the San Gabriel Valley, the L.A. basin and Orange County.

Though most of the birds have been born in the wild, their ancestors escaped after being brought here as pets, or to be bred. Though initially few in number, they found each other and multiplied.

"In terms of how long they have been loose, the red crown parrot, which is among the most numerous in the area, can be traced to the 1950s," Garrett said. "You can dig up references to free-flying parrots (in Los Angeles), as long as there is a record of European people here." Most of the flocks, he said, seem to have been established between the 1960s and 1980s.

"Near where I am, there is a flock of over 60 birds," said Susie Kasielke, who lives in Pasadena and is the curator of birds at the Los Angeles Zoo.

Garrett said the wild birds would not make great pets for anyone inclined to try and nab one and avoid the sales tax a pet store could charge.

"They're nasty," he said. "They will bite you at any opportunity. They're aggressive toward people."