WASHINGTON - Could the National Zoo's female panda be pregnant? ABC 7 News reporter Cynne Simpson looked on Monday morning as a veterinarian performed an ultrasound to check for any signs of a cub.

When Tai Shan was born in 2005, everyone fell in love with their little "Butterstick." But after he moved to China last month, D.C. residents are hoping Tai Shan's mother, Mei Xiang, will have another cub.

"I think it'd be a great addition to the zoo to have a new baby panda" said D.C. resident Michelle Morra.

In January, veterinarians artificially inseminated Mei Xiang. Now every week, the panda rolls onto her back for an ultrasound and some apple and pear slices -- apparently a treat well worth the effort.

Veterinarian Dr. Suzan Murray looks for any signs of pregnancy, including changes in the width of the reproductive tract.

Murray didn't see any evidence of an embryo Monday, but it still might not be visible for weeks. There's also a chance Mei Xiang could have a pseudo pregnancy.

"It's a time during which the reproductive tract changes and the hormonal profile mimics regular pregnancy -- but at the end there is no cub born," she explained.

Kathy Ballard and her granddaughter, Katie, traveled from Michigan to visit the pandas. "She loves pandas -- so rare to have [an] opportunity to see a real one," Ballard said.

Katie says she'd be thrilled if Mei Xiang had another cub. "I like little babies," she said.

And now that Tai Shan is gone, curator Lisa Stevens says they're counting on Mei Xiang.

"We're very hopeful," noted Stevens. "We're missing having a cub around the panda house, so we really hope she'll come through for us this year and we'll have another cub."