The bird books describe egrets as being gregarious. In fact, one text says, gregariousness -- the inclination to associate with others of one's kind -- is their outstanding feature.

It's not unusual for many species of nature's creatures to hang around "with their own kind" although there are many others who play the solitary game.

But for a flock of wild egrets to carry their togetherness over to a close association with man, in one of man's worst environments -- a freeway interchange -- is enough to raise some Audubon eyebrows.

Yet, in recent weeks, a score or more of cattle egrets -- white-plumed, long-necked, long-legged and long-billed -- have chosen to feed in a patch of grass hemmed in closely on all sides by roaring traffic.

The site is at the Jamboree Boulevard overpass of the San Diego Freeway in Irvine, Calif., about 32 miles southeast of downtown Los Angeles. The grass, made lush by rains, is bordered by the on-ramp and off-ramp cloverleafs.

This means that cars and trucks generally traveling at high speeds pass within a few feet of the birds. But they seem unruffled.

"I have no idea why they would choose a place like that," said Gordon Marsh, director of the Museum of Systematic Biology at the University of California at Irvine.

"We do know that the population of cattle egrets seems to be growing."

Cattle egrets, as their name implies, usually congregate among herds of cattle, snapping up the bugs and small frogs or lizards that expose themselves when trying to get out of the way of bovine hooves.

"Any bug that jumps away from a hoof when an egret is around has made a fatal mistake," Marsh said.

Greg Nuessly, a laboratory assistant at the museum, said that cattle egrets were first seen in the Irvine area in 1964, that they are known to migrate to some extent and that more and more of them are showing up here each year.

The birds stand about 20 inches tall and have wingspreads of up to 4 feet.

The flock that feeds by the freeway seems to do so mostly during the morning rush hour. When traffic eases off after midmorning, the birds fly to nearby but more sequestered fields.

Like white-tailed kites and other hawks, whose habitats are being taken over by housing developments, these egrets have turned to the "open spaces" along the freeways -- seemingly aware that men do not triad there.