Anyone driving through the Upper 7th Ward on a Friday afternoon might see David Robertshaw pushing a giant red box on wheels down the street. Pausing every now and then to catch his breath, he continues to St. Bernard Avenue and stops in front of Sidney's Saloon.

  Here, Robertshaw gets down to business — cooking for his pop-up Bird by Bird. The metal box protects his charcoal-burning clay tandoor oven, from which he delivers blistering pieces of chicken and lamb. As the sun dips behind the shotgun houses in the neighborhood, customers line up for paper boats filled with their choice of meat, slices of soft, charred flatbread, and a creamy yogurt raita to cool the spice-tinged meal.

  A construction worker with a culinary degree, Robertshaw spent the better part of a year fashioning the mobile oven. His idea for an Indian pop-up restaurant had been simmering for some time, well before he fell in love with New Orleans and its entrepreneurial, anything-goes spirit. He moved here from Washington, D.C. a few years ago.

  "It's a place where things like this can happen, and people don't just talk about doing things, they actually do them," Robertshaw says. "I'm pushing a 500-pound box of fire down the street — you couldn't get away with that in D.C."

Bird by Bird is one of the newest pop-ups in a city with at least 50 — and the number is growing. The pop-up dining movement has been building traction in New Orleans and across the country for a decade, but the last few years have seen it become a fixture on the local food scene. Diners find pop-ups an easy way to experiment with unfamiliar cuisines and try new culinary concepts.

  The world of pop-ups is fluid, and no two are alike. The participants include chefs and entrepreneurs of all calibers and experience levels, from self-taught bakers selling their pastries at local coffee shops to line cooks branching out from their day jobs to established chefs with a new idea. Prospective pop-ups also must find a host and make arrangements that benefit both businesses.

  Bacchanal, a Bywater wine shop-cum-garden party, was an early player in the days following Hurricane Katrina and the levee failures in 2005. It became an integral part of the recovery effort when it opened its kitchen to chefs from around the city who had lost their jobs or restaurants. As New Orleans grew, roving chefs found opportunities to showcase their skills and make extra cash by taking up residencies at local bars with functioning kitchens that lacked the staff or the means to provide food service.

  Dean Lambert, director of the New Orleans Pop-Up Association, says the movement reflects a national trend where diners and chefs are moving away from the high-end restaurant model to more casual dining platforms. It's also part of what he calls "the share economy," where established restaurateurs and culinary newcomers find common ground, sharing spaces and helping each other cross-promote business ventures.

  "New Orleans can be behind on some things," says Lambert, who with chef Cristina Quackenbush runs the Filipino restaurant Milkfish in Mid-City. "But in this case, it appears to be ahead of the curve — and it's the perfect [city] for it, because there is so much underutilized space."

  Milkfish is an example of a pop-up that came full circle. Quackenbush, a native of the Philippines, began developing the idea for a Filipino restaurant in 2012 while working at High Hat Cafe and Adolfo Garcia's Rio Mar. Garcia encouraged Quackenbush to host a series of dining events at his restaurants. She began selling her chicken adobo, lumpia and pancit noodles during nightly residencies at Marie's Bar and Who Dat Coffee Cafe in the Marigny. After two years, she and Lambert opened their first brick-and-mortar restaurant on Carrollton Avenue. They now open that space to new pop-ups and restaurant concepts on Wednesdays, giving friends and fellow cooks a chance to realize their concepts, build support among diners and learn the essentials of running a business.

  For up-and-coming cooks who don't have the capital needed to open a restaurant, operating a pop-up at a bar or dining venue can provide an affordable test run. Lots of local businesses have offered aspiring chefs nightly residencies, including Pal's Lounge, which currently hosts the meatball-centric StickBall, and Dante's Kitchen, which hosted both Noodle and Pie and McClure's Barbecue before each went on to open restaurants. Dante's Kitchen now opens its kitchen to employees Rosie Jean Adams and Jordan Deis on Tuesday evenings for their pop-up Sarsaparilla, which serves creative cocktails and tapas-style snacks such as octopus carpaccio and fried pickles with dill aioli, while local musicians perform.

For husband-and-wife chefs Amarys and Jordan Herndon, The Old Portage pop-up is a chance to combine their culinary styles and experiment with dishes outside the confines of their day jobs — Jordan is a sous chef at Ralph's on the Park and Amarys was a sous chef at Bayona.

  "We were at a spot where we really wanted to work together and after working at both of our restaurants, we realized that we had a lot of the same focus and a lot of the same ideas," Amarys says. She describes her cooking as globally influenced and says Jordan focuses more on classic New Orleans and Southern cuisine. The pop-up is at NOLA Brewing Tap Room on Tuesdays and The Black Penny on North Rampart Street every other weekend.

  "It's been invaluable," Amarys says. "It's so much lower risk for [us] to learn all these things about the business with a baby pop-up instead of a real restaurant."

  Tres Barnard's We've Got Soul popped up at bars in the Marigny and Bywater in 2012, offering patrons soul food-inspired cuisine. After three years as a pop-up and a crowdfunding campaign that netted more than $16,000, Barnard found a permanent home at Carrollton Station, where he cooks a changing menu of Southern-inspired dishes four nights a week.

  "It's still a lot of work and it's all on your shoulders," Barnard says. "You're doing literally everything yourself, building a restaurant from scratch. Everything that you do has to come from your two hands."

  Part of what makes pop-ups so attractive to chefs is the low start-up cost and smaller financial losses if the venture fails. While some pop-ups become permanent restaurants, the majority stay on the pop-up circuit or fade away.

  Cam Boudreaux and April Bellow operate Killer Poboys — arguably one of the most successful pop-ups in the city — and recently opened their first brick-and-mortar restaurant on Dauphine Street. Their taco spinoff at Molly's in the Market, however, fizzled after a year.

  Matthew Kopfler, who runs the farmers market-driven L'enfant Terrible in the same spot at Molly's, says he's tailored his menu to appeal to heavy-drinking patrons, and his menu of vegetable curries and pierogies has proved popular with the late-night Decatur Street crowd.

  "You can have an idea that's great, but it might not work," Kopfler says. "You have to fit the market. That's the cool thing about the pop-up: You can have this idea that fails, maybe lose a couple of thousand dollars, and move on to something else."

Pop-ups that operate out of an existing permitted restaurant must obtain a special event permit, according to city officials. But if a pop-up uses a space in a business that isn't needed year-round, it is likely the New Orleans Fire Department and state fire marshal will allow it. Pop-ups also are required to charge sales tax and remit them to the city monthly.

  Most people interviewed for this story say they obtained their own occupational or catering license or piggybacked on the license of their host bar or restaurant. A few, who asked to remain anonymous, say there is little threat of getting shut down for failing to have a permit and that some first-timers who take over a friend's bar or shop for a day or two don't bother with permitting at all.

  There's been little pushback about what appear to be legal loopholes, and the pop-up scene in general receives positive feedback from diners as well as restaurant chefs — a major departure from the contentious battle over food trucks in 2013. At that time, a city ordinance was proposed to regulate the growing industry, limiting the number of trucks allowed to operate and specifying where, when and for how long trucks could serve customers. Members of the Louisiana Restaurant Association wanted to protect restaurants from the competition of a cheap dining alternative parked outside their doors and argued the food trucks did not have to abide by the same rules and regulations as permanent businesses. The ordinance that passed allowed for up to 100 food truck permits.

  Food trucks are a popular alternative for chefs seeking a venue to cook and serve food, but the costs involved in operating a mobile food vending business are much higher than the overhead needed for an occasional pop-up.

  Mark LaMaire collected Burmese recipes while traveling in Southeast Asia and incorporates them into a weekday lunch his pop-up Lahpet offers at Milkfish, featuring dishes including pickled tea leaf salads and fish curries.

  At Fatto Bene, friends Tyler Agin and Josh Bragg create the handmade pastas and regional Italian dishes they fell in love with while working at a Roman restaurant in Norfolk, Virginia. Both men work full-time jobs at Peche but hold monthly events at Bao & Noodle, where they serve dishes like tortellini en brodo and gnocchi tossed with gorgonzola and radicchio.

  Black Swan has been popping up at Milkfish and holds events at local music and art festivals. Chef Nikki Wright and General Manager Shana Turner run the Caribbean- and Thai-inspired soul food operation, which features dishes like sweet potato curry with crispy plantains and braised oxtail with three-cheese macaroni.

The life cycles of pop-ups don't always follow the same trajectory, and established chefs with restaurants of their own are jumping into the game. Michael Gulotta, chef/owner of MoPho in Mid-City recently opened the Sicilian-inspired food pop-up Tana at the Tulane Avenue cocktail bar and art space Treo. Tana allows Gulotta to experiment with Italian dishes inspired by his grandmother, including handmade pastas and regional seafood dishes. Gulotta's team also runs the pub grub Rum and the Lash, which took over the kitchen at Finn McCool's Irish Pub.

  Coquette chef Michael Stoltzfus and Meauxbar's Kristen Essig opened their Southern-accented pop-up Little Bird inside the Lower Garden District whiskey haunt Barrel Proof as a passion project.

  "We wanted to do something together, and we happened to live right across the street [from Barrel Proof]," Stolzfus says, "so we figured: Why not?"

  After realizing the project's demands, they brought on their friend John Sinclair to run most of the day-to-day operations. Little Bird offers a menu of fried chicken sandwiches, Broadbent country ham with beer mustard aioli and charred broccoli served under a Worcestershire and liquid cheddar sauce.

  Somewhere between the casual bar residencies and standalone restaurants, the city is becoming home to another platform, something pop-up restaurateurs Brandon and Jennifer Blackwell call the "intermediary" zone. It's a spot the proprietors of Splendid Pig and Elysian Seafood both occupy at the new "food port" Roux Carre in Central City and at food hall St. Roch Market, respectively. Both Roux Carre and St. Roch Market act as incubators for up-and-coming business ventures in the food world.

  "Over the last few years, everyone has the sense that the restaurant scene in the city has become so flooded with permanent brick-and-mortar places," Jennifer says. "When this thing at St. Roch Market came up, it definitely seemed like a great opportunity to hone everything and develop a following before we get to wherever that next step is."

  Like the Blackwells, many pop-up operators aspire to open a permanent restaurant, but recent restaurant closings induce hesitation.

  "It's definitely scary," Brandon says. "There's a lot of feeling out there ... that the food scene in general might be shifting more towards a more causal side of things, away from the old guard of super fine dining. Hopefully restaurants do have a future — and I think they will — but what form that's going to take is going to be something different than what it ever has been in the past."