April is here, the sap has riz, I wonder how the pandas is? -- Hubert Romans

The lady panda began walking backwards yesterday and this is a hint she may soon be ready to breed.

At the National Zoo, where it is hoped the visiting pandas from London (Chia-Chia) will sire a wee panda, excitement has begun to rise higher among the humans than, possibly, the pandas.

Ordinarily Ling-Ling, the zoo's female, enters her estrus about May 15, but the signs are strong now that it will be earlier for her this spring.

She was bleating a good bit over the weekend, and then this walking backwards business. Yesterday, Hsing-Hsing, the zoo's male, who has not been an effective breeder at all, began calling back to her. They met briefly and Hsing-Hsing mounted, but no breeding took place.

MEANWHILE, the Londoner has seen the lady once, when he spied her through the moon gate, and she growled at him and he growled at her and they went their separate ways. But have no fear, both the London panda and the Washington female have explored each other's outdoor runs, separately, and alone.

This means, the zoo officials home, that when the magic moment comes they will not be distracted by some new environment or new scents.

"Chia-Chia is to be the primary breeder," said Ilene Ackerman yesterday, responding to inquiries how love is coming along. "With two males in residence, plus the female, we hope everybody will stimulate everybody else."

The resident male, who has not succeeded in impregnating Ling-Ling in the past, could conceivably breed with her this year, which could raise a question what to do with the visiting Londoner. But it is assumed the resident male will play around as usual and that the visitor will be the sire.

But of course animals are given to delicacy in these matters, and nobody knows yet if the Londoner and the Washington girl will hit it off. What if they take an instant dislike to each other? Or what if the Washington male and the London male both -- how would paternity be established? What if --

Never mind all that. The first thing is to get Ling-Ling fully ready to breed and Nature, it is hopefully, has now started that lovely process.Further details will be, God willing, forthcoming within the next few days.