In the tradition of Ed Wood, amateur director James Nguyen's passion for cinema gave birth to an awful film made on a shoestring

• Tippi Hedren, with Birdemic director James Nguyen, makes a cameo appearance in the new film. Picture: Complimentary

In panoramic shots, it shows an idyllic California town – streets, parking lots, a pumpkin farm, horses. These scenes continue for more than a minute, until the ambient noise is punctured by menacing screeches.

Suddenly the sky is filled with birds: badly animated birds, out of proportion to the buildings below – birds that barely flap their wings as they glide by. Occasionally an aggravated fowl breaks away from its clipart flock, plummeting to the ground and exploding in a similarly unconvincing plume of smoke.

James Nguyen, the 43-year-old writer and director of Birdemic, a would-be thriller about an avian rampage, will be the first to tell you that it is far from a perfect film. But, as he said recently, "if it was perfect, in every angle and the visual effects and everything, maybe it wouldn't be where it is today".

Since Birdemic was discovered at the 2009 Sundance Film Festival – where Nguyen brought it anyway and showed it in bars after it was rejected by the selection committee – it has become a cult hit on the midnight movie circuit in the United States.

Crowds in Austin, Texas, Phoenix and Los Angeles have thrilled to its stilted dialogue, substandard production values and young heroes who defend themselves with coat-hangers. (A Birdemic US tour is currently booked until the end of May.)

Birdemic has spawned a discussion about why, of all the Z-grade movies that are made each year, this particular one should find favour with audiences. What has made Nguyen a latter-day anti-genius to rival Edward D Wood jnr, whose 1959 horror dud, Plan 9 From Outer Space, became legendary for its countless defects? "It's something unexpected," Nguyen says. "Maybe it's meant to be like that."

Evan Husney, who now works for the independent distributor Severin Films, was also at Sundance, where he spotted Nguyen driving a beaten-up sports car decorated with a prop eagle and fake blood, and blaring bird noises from its stereo. "On the side of his car he had spelled the name of his own movie wrong," recalls Husney. "He had spelled it 'Bidemic', without the R." Intrigued, Husney met Nguyen at a sparsely attended Birdemic screening. The movie, Husney says, looked "like a Super Nintendo game – it was the funniest thing I had ever seen in my entire life," he adds.

More fascinating was Nguyen himself, a Silicon Valley software salesman whose family fled Vietnam in 1975 before the fall of Saigon and who grew up in the US enthralled by movies such as the 1980 Christopher Reeve romance Somewhere in Time and Franco Zeffirelli's Romeo and Juliet. "But romance alone is not enough for me," Nguyen says. "I'm not just interested in a chick flick."

In 2008, as a tribute to Alfred Hitchcock's The Birds, Nguyen spent $10,000 (about 5,000 at the time) and seven months' worth of weekends making Birdemic. "I never went to film school," he says. "But I did go to what you'd call the film school of Hitchcock cinema."

The investment seemed to pay off when Severin Films, which has handled the DVD releases of films like Enzo Castellari's The Inglorious Bastards and Richard Stanley's Hardware, acquired Birdemic and began showing it at speciality cinemas across the country. Along the way, Birdemic received encouraging notices from the geek-culture television series Attack of the Show, the horror movie website bloody-disgusting.com and even ew.com, the website of Entertainment Weekly.

Exactly why Birdemic has been greeted so warmly is up for debate. Gabe Delahaye, the senior editor of the satirical pop-culture blog videogum.com, which has tracked the bewildering progress of Birdemic since July last year, says the film was remarkable for how its aspirations in no way align with its results.

If Birdemic were simply a cheaply-made horror movie, of which hundreds are made each year, Delahaye says, "you'd just be watching something with grand ambitions not being able to achieve them". But in this case, "the fact that it is low-budget didn't have any effect on what he was trying to do. Because who knows what he was trying to do?"

The comedians Eric Wareheim and Tim Heidecker, who star in the TV series Tim and Eric Awesome Show, Great Job! and who hosted the Los Angeles premiere of Birdemic in February, say that film-makers such as Nguyen are happy that people are watching their movies, even if only to make fun of them.

Wareheim compares Nguyen to such film- makers as Tommy Wiseau, whose byzantine drama The Room has also become a hit midnight movie, and Mark Borchardt, the frustrated horror director profiled in the documentary American Movie.

"What they really care about," Wareheim says, "is that they're going to be recognised and people are going to watch it, and people are going to talk about it, even if it's bashing them. They're just happy to eat the meal that was provided to them."

Heidecker questions whether Nguyen understood that audiences have been coming to Birdemic for its unintentional comedy. "I was sitting next to James at the screening," he says, "and he was giddy, shaking with laughter and high-fiving me, 'This is the best, I did it. What are you laughing at?'" Asked about the Los Angeles screening, Nguyen says: "A few people there, they were laughing at my movie. But I think the majority who were there really laughed with it."

Gabe Delahaye thinks there is nothing cruel in finding humour in the works of these maladroit directors. "It's not like they had a movie that was just for their friends and family," he says, "and then a jerk took it and was like, 'Look at this idiot and the movie he made.' They made a movie and tried to promote it, and it became something that might not be what they originally intended."

Nguyen says he has not been discouraged by the experience of Birdemic. "That's the risk that I take in making a movie," he says, "to be judged, to be reviewed – the good, the bad and the ugly. And so be it." Indeed, he is already at work on his next feature. It is a serial killer film called Peephole: The Perverted.

For more on Birdemic, visit the film's website, www.birdemic.com