A beer bottle was lit up like a Christmas tree on one Facebook page and flanked by stuffed animals in another.

Then there were the iPhone apps that allowed drinking enthusiasts to hunt for virtual trophies or monitor the weather through drink prices, and the video on YouTube that featured cartoon characters using spirits to reduce stress.

David Jernigan came across these alcohol advertisements during a recent study of social media. And he says that while they may be effective marketing for legal imbibers, they're also appealing to kids.

The alcohol companies' voluntary limits on print, radio and television that alcohol companies are largely being ignored online, concluded Jernigan, director of the Center on Alcohol Marketing and Youth at the Johns Hopkins Bloomberg School of Public Health.

"We tried to get a sense of everything the companies are doing on Facebook, YouTube, Twitter, Flickr and iPhone apps and it's amazing how much they're doing," said Jernigan. "It's far more than I think most parents or adults are aware of. It's the wild west without a sheriff."

Associations representing alcohol companies say they've developed voluntary codes for advertising in social media, similar to those crafted for traditional media outlets.

"The spirits industry is committed to responsible advertising regardless of the medium," the Distilled Spirits Council said in statement. "Social networking sites are used primarily by adults, which makes these platforms responsible and appropriate channels for spirits marketers."

Jernigan said there's no way to determine how many kids are seeing, or responding to, the alcohol marketing. But considering their heavy social media use, he concluded, "it's probably a lot."

He said 13- to 20-year-olds make up about 13.6 percent of the population but about 22 percent of Facebook users.

A May study from Consumer Reports found that amounts to about 20 million Facebook users under age 21. More than a third were actually younger than 13 — violating the site's terms — and their accounts were largely unsupervised by parents.

They could be among the 6.7 million people who "liked" the 10 Facebook pages the center studied or the large number of fan-uploaded photos and videos.

Jernigan said seeing such content can make a lasting impression. He cited 14 studies finding evidence that exposure to ads influences whether young people start drinking and how much. He said about 4,700 underage youth die from excessive alcohol use each year.

Tighter controls on content, more parental involvement and better technology to limit underage access are needed, he said.

The Distilled Spirits Council said it calls on companies to advertise in any medium only when close to three-quarters of the audience is reasonably expected to be age 21. The group cited Nielsen data from August that show about 82 percent of Facebook users, 87 percent of Twitter users and 81 percent of YouTube users are at least 21.

Codes also call for inappropriate user-generated content to be removed and age-affirming technology be used before direct dialogue is allowed with consumers. And as evidence the companies are not increasing their influence on kids, the council cited newly released federal statistics that show alcohol consumption rates among eighth-, 10th- and 12th-graders are declining.

The National Institute on Drug Abuse, part of the National Institutes of Health, found alcohol use dropped to its lowest point since monitoring began in 1975. Though, alcohol is still "the drug of choice" among all the age groups, and almost 64 percent of 12th-graders reported drinking alcohol in the past year.

A digital marketing consultant to the Distilled Spirits Council said he didn't believe the sites were deluged with children. Kids on Facebook with or without their parents' consent were most likely looking to engage with other kids, said Hemanshu Nigam, chief executive of SSP Blue, an online safety and privacy firm, and the former chief security officer for MySpace.

And even if they do visit a site with adult content, technology can screen them. Sites like Facebook use information gathered on users to appropriately target ads. Companies also can use age gates and skim comments and other content to find and block underage users.

"There are a bunch of things companies can do to say to kids this isn't for you, and if you don't go away, there are people dedicated to stopping you," he said.