SAN DIEGO -- One of the San Diego Zoo's more famous inhabitants, giant panda Hua Mei, was feted Wednesday on her third birthday, expected to be the last she spends in San Diego before she is sent to live in China.

The zoo's agreement with China governing the loan of Hua Mei's parents, Bai Yun and Shi Shi, says any offspring belong to China and must be sent there on or about the animal's third birthday.

The zoo doesn't yet know exactly when Hua Mei will depart. But, Don Lindburg, the zoo's giant panda-team leader said that could take place in the next two months or so.

San Diego's loss will be the Wolong breeding center's gain, Lindburg said. He called Hua Mei a "super animal."

"She's not been sick a single day in her life, and she's very active, easy to care for," Lindburg said. "She understands human commands -- though she might have to learn a little Chinese. I think they'll be most pleased to get her."

Lindburg said he and others who have worked with Hua Mei have formed strong attachments but will have to "put aside our emotions for the good of the species."

"She'll leave a big hole," he said. "Every day it's a delight to see her. She's still quite playful."

The 200-pound Hua Mei could get a little bigger, but her growth has leveled off, Lindburg said.

"She's adult-sized now," Lindburg said, although "she's not socially or sexually mature yet."

She could have her first estrus -- when she would be fertile -- in her fourth or, more likely, fifth year, Lindburg said.

Zoo officials would have liked to help bring forth a Hua Mei sibling, but that doesn't seem to be in the cards.

The zoo announced Tuesday that researchers have discontinued a round-the-clock birth watch on Hua Mei's mother, 11-year-old giant panda Bai Yun, who was artificially inseminated in March.

"The Giant Panda Conservation Team began to notice that Bai Yun was diminishing her nesting behavior, giving the team an indication of a pseudo or false pregnancy," a zoo spokesperson said.

Researchers had been watching Bai Yun for nearly a month in a maternity area not accessible to zoo visitors. Her behavior and hormonal levels were studied and compared to patterns of giant pandas that have given birth.

Hua Mei underwent three artificial insemination procedures involving frozen semen from Shi Shi. It was the first time frozen semen had been used for the procedure at the zoo. Shi Shi's advanced age was cited as the reason for foregoing the collection of semen this year.

Pandas are fertile for only about 24 to 72 hours once a year, and there is no sure way to verify a panda pregnancy. In 1999, keepers didn't know Bai Yun was pregnant until three days before Hua Mei's birth.