Another "winged target" from the Soviet Union has flown off course and, landing in Nebraska, is attracting the attention of hundreds of specialists.

The target is not a missile but an anser fabalis, also known as Middendorf's bean goose. Several hundred bird watchers have flocked to the DeSoto Wildlife Refuge north of Omaha for a glimpse of the Russian bird, which customarily migrates from the Arctic coast of Siberia to southern China for the winter.

According to Thomas F. Prusa, DeSoto's assistant wildlife manager, this particular Middendorf's bean goose was "about 8,000 miles off course."

The excitement at the usually quiet watering hole began Dec. 29 when two unnamed graduate-student ornithologists were participating in the National Audubon Society's annual bird count.

As they checked a flock of white-fronted geese flying from the north, they noticed that one bird did not have the usual "white front" around the bill; instead, it had a yellowish-orange band. And it wasn't to be found in the Audubon field guide to North American birds.

"We knew we had something unusual," because for three days no one could identify the stranger, Prusa said in a telephone interview. "By Wednesday, we had some experts up from Omaha and identified it as the Middendorf's bean goose."

The bird, which eats beans in fields, is about as prevalent in the Russia-to-China migration belt as the Canada goose is in North America. On the North American continent it is rarely seen farther east than the western Aleutians.

"This one got lost somehow," Prusa said. What drove the bird off course isn't known, but warm weather and a late migration may be the causes.

Prusa said the bird apparently is content to mingle with Canada geese and mallards on DeSoto Lake. Most of the lake surface is frozen.

"Normally, there wouldn't be any birds here now," Prusa said of the estimated 350 waterfowl still on the refuge. "They'd normally be gone by Christmas."

The bean goose "is strutting around, sleeping and preening," Prusa said. "We're not expecting cold weather for several days, so he'll likely stay until then."

If the bean goose stays with the flock of white-fronted geese, it most likely will end up on the Gulf of Mexico for the winter, rather than in southern China, Prusa said.

Ione Werthman, president of the Audubon Society of Omaha, said: "I never thought I would sit three hours and watch a bird. It paraded around for us as nice as you could ask a bird to."

G. Philip Million, public affairs director of the U.S. Fish and Wildlife Service, said, "There are probably hundreds of people who will now want to get on a plane, when they read about this, and fly out there." CAPTION: Picture, Yellowish-orange band around its bill distinguishes Middledorf's bean goose. Copyright (c) 1982, Wild Bird Society of Japan