SAN DIEGO -- An "adult-sized" Hua Mei will celebrate her 3rd birthday Wednesday at the San Diego Zoo, and that means the giant panda's move to her new home in China can't be far behind.

The zoo will offer the youngster a birthday cake made of ice, with "appropriate foods" such as carrots and apples enmeshed inside, said Don Lindburg, the zoo's giant panda team leader.

This is a milestone birthday, since the zoo's agreement with China governing the loan of parents Bai Yun and Shi Shi says any offspring belong to China and must be sent there on or about the 3rd birthday.

The zoo doesn't yet know exactly when Hua Mei will depart, but Lindburg said that could be anticipated in the next two months or so.

"The significance is, of course, that it is appropriate for her to go to another place because the only male here is her father," Lindburg said.

To begin "her own reproductive career in a year or two, she needs to be where she can be with another male," Lindburg added.

Lindburg said he and others who have worked with Hua Mei have formed strong attachments, and 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. "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.

Those on hand for Wednesday's celebration will have a chance to sign a large birthday card, and children will make special bamboo crafts.

Zoo: No Siblings For Hua Mei, Yet

Zoo officials also announced Tuesday that researchers discontinued a round-the-clock birth watch on 11-year-old giant panda Bai Yun, who was artificially inseminated in March.

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"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 representative said.

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

The panda underwent three artificial insemination procedures involving frozen semen from Shi Shi, the male giant panda living at the zoo.

This 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 this year.

Hua Mei was the product of artificial insemination.

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.