The roaming herds will arrive in a mass of golden yellow, then erupt in a rainbow of colors and a cacophony of calls. "Stay together" is the most common, but those listening closely may also hear, "How much is that?"

It's almost field trip season for the Pittsburgh Zoo and PPG Aquarium, and a new partnership in the zoo's gift shops faces its first stampede test this spring when as many as 10,000 schoolchildren may visit in a single day.

"They all have to be out of here by 2 p.m., and they're only given a half hour in the gift shop," said a bemused Ivan Gartner, vice president and general manager, eastern region, for Service Systems Associates, a Colorado company that's been running the shops at the zoo long enough to know this routine

Retail operations inside museums, galleries and zoos always bring challenges. They're often afterthoughts in places devoted to a higher cause such as educating the public about endangered species or perhaps raising interest in Picasso and Matisse. And shopping patterns vary wildly, depending on the weather or the latest exhibit opening.

"The selling time's so short. You have to do things quickly," said Sreedhar Nair, director of sales and marketing for the software division of K&M International, a Twinsburg, Ohio, company partnering with Service Systems Associates to try to boost sales in the zoo stores.

After steady years of growth, sales per capita have fallen about 3 percent since Sept. 11, 2001, about the same time that zoo attendance dropped.

"It hasn't been dramatic, but it's been noticeable," said Gartner.

The plan is to turn things around with a combination of the latest retail technology to track what shoppers are buying and a deeper inventory of zoo-relevant stuffed animals and toys ready when the customers are. K&M brings both software and merchandise to the venture, since it might be best known for its Wild Republic zoo-relevant stuffed animals and toys.

Over the past few months, the partners have installed point-of-sale systems like those used in Target and Wal-Mart to track purchases from each register. "On a day-to-day basis, we will know what's moving and what's not moving," said Nair.

If every 7-year-old girl -- the shops' core demographic -- needs a $5.95 Wild Clinger frog with magnetized feet, the stores will be able to quickly track the demand and order more.

The partnership also gives the stores access to piles of new Wild Republic merchandise, some of which was actually developed for this market.

A line of soft animals called Cuddlekins, for example, didn't come in enough sizes for the Pittsburgh operators' taste. So within a month, Wild Republic got the factory to deliver larger versions of the 12-inch polar bears, snow leopards and so on. The 16-inch samples are now available for $19.95 at the Safari Outpost, although it'll take at least three weeks to get more in stock.

The new Cuddlekins are being rushed in via expensive air routes, a decision that reflects both the oncoming May rush -- the zoo version of the Christmas shopping season -- and the importance the partners place on this venture.

Both companies hope to take what they learn here to Service Systems Associates' other operations, which include stores at the Detroit Zoo, the Minnesota Zoo and the Los Angeles Zoo.

In addition to inventory tracking, K&M's participation has opened up time-honored retail techniques such as offering promotions, perhaps a free plush toy with every $30 purchase or running a sweepstakes contest for a $300 shopping spree. The goal is to increase the average purchase at the stores, which now sits in the $12 to $13 range.

Access to K&M inventory also should mean the staff won't have to close two of the three shops during the quiet winter months. In the past, there wasn't enough cash coming in to justify stocking the stores at in-season levels.

That meant less selection for the brave souls who did come in, as well as the shops missing out on the nice sales bumps that a few 60-degree days in February can bring.

If the various experiments work, zoo officials would welcome a bigger contribution to the annual $11 million operating budget.

Service Systems Associates' Gartner declined to release sales figures, but he said the vendor leases the gift shop space and contributes between 10 and 30 percent of gross sales to the zoo, depending on the merchandise.

Both partners cultivate their reputation as zoo boosters by setting up relationships with groups such as the American Zoo and Aquarium Association. The National Audubon Society approves details of a line of Wild Republic birds as well as the attached hang tags offering information on the species. New in-store signs describe the real animals that the stuffed ones portray.

The vendors also try not to cross the line on what can legitimately be sold in a zoo shop trying to balance commercial and educational interests.

"You're not going to see pink elephants," promised Gartner. "You're not going to see an animal with a bow tie on it."