A rare bird, identifiable without binoculars by its 28-foot length and white plumage, has alighted in Evanston. Enthusiasts seduced by its song – a brief text or tweet – can locate it as it wheels along the broad streets of Evanston and its environs on round rubber “wings.”

Evanston’s first and only food truck, Hummingbird Kitchen, is named for a tiny bird that is in constant motion. The truck is unique in the Chicago metropolitan area in holding a license for onboard cooking. As a result, it is more a mobile kitchen than a rolling food vendor.

Though new to its Evanston habitat, Hummingbird Kitchen reflects a craze hatched earlier on the East and West coasts. In New York, long-time fans of pushcart vendors now also flock to four-wheeled purveyors of sophisticated fare. New York magazine calls the phenomenon of the food truck “the next step up the evolutionary ladder from the traditional sidewalk food cart.”

Foodies across the county have embraced the trend as well.”Now many, many American cities have a thriving fleet of gourmet food trucks in a world of flavors,” notes the online magazine Shine.

Despite its successful predecessors, Hummingbird at first appeared to have flown to Evanston on a wing and a prayer.

The truck pulled into town last June boasting an eye-popping kitchen, custom-designed and equipped to serve 100-150.

But it lacked what seemed essential to its success: a license to cook in that remarkable kitchen the food its owners intended to sell on the street.

At the time, laws in Evanston and greater Chicagoland limited trucks to selling pre-packaged foods or food cooked in commercial kitchens rather than on the trucks themselves.

Though that made Hummingbird Kitchen look like risky business, its backers insist they had an infallible plan all along.

Restaurateur Stephen Schwartz had partnered before with Chef Vince DiBattista and Heather Falconer Behm, at Campagnola and Union Pizzeria. The notion of “a like-minded business” that was not another brick-and-mortar eatery was attractive, he says. He had considered a food truck earlier but says he decided to wait till after launching Union in 2008.

Having designed the truck of their dreams – one with, among other amenities, 12 burners, a deep fryer, a 36-inch flat-top, convection ovens, a large refrigerator, a three-compartment sink and a steam table – the partners were not about to watch it languish at the curb.

If denied a permit from the Evanston City Council to cook and serve street food, says Ms. Behm, they had decided Hummingbird would focus on the other two prongs of their three-pronged business plan: private events and production catering.

Last summer Mr. Schwartz and Ms. Behm paved the way to a license by talking to and winning the support of the aldermen of the wards in which they live, as well as the alderman in whose ward Campagnola and Union are located. Having the two restaurants helped their cause, they say.

In September City Council approved a food truck ordinance by an 8-to-1 vote. It took till November, Mr. Schwartz recalls, to finalize the details. Hummingbird Kitchen had to pass a Health Department inspection and agree to such constraints as limiting its travels to wide streets, parking only in seven or eight designated spots and keeping a specified distance from the beach.

Hummingbird Kitchen, with work space for a staff of three to five, can “make any venue a restaurant,” says Mr. Schwartz. The “fun factor of the truck” can become “an interactive part of a [private or corporate] party,” he says. Truck chefs can turn out fancy food like Campagnola’s signature trout with confit of melted tomatoes and almonds, then drive away without dirtying the hosts’ kitchen.

Parked at Foster Street and Sheridan Road near Northwestern University – or this summer at Sheridan Road and Greenwood Street, en route to the beach – it becomes a street-food emporium, offering items designed to be eaten out of hand or in a cup: crabcake sandwiches or tuna melts or porcini mushroom soup.

The truck is its own best publicity, a moving billboard that attracts plenty of attention. But updating the public about its whereabouts is more difficult. Ms. Behm has found a timely way to alert fans about its peripatetic, once- or twice-weekly vending schedule. While food trucks elsewhere have relied on tweets, she draws in the more reluctant over-30 crowd by sending text messages – one each day the truck goes out – to those who text “hummingbird” to the number 96362.

One of the challenges of the business, say Ms. Behm and Mr. Schwartz, is balancing the functions – keeping the truck free enough to accept catering jobs while maintaining a presence on the streets of Evanston.

Mr. Schwartz is clear on at least one of its rewards. Aboard the food truck, he says, “there’s nothing between the kitchen and the customer.” In the restaurant, he says, “Lots of times the cooks don’t see the reaction” of the customers, while those at the front of the house miss seeing the cooks at work. Mixing it up in the Hummingbird Kitchen, he says – moving front staff to the back and vice-versa – is fun.