FORT WORTH, Texas -- From flipping burgers to watching over swimmers, the summer job has been a rite of passage for countless teenagers.

But this year, youngsters nationwide may have to hunt a bit harder to land their first paychecks.

Teen employment has been falling since summer 2006, and it's expected to reach a historic low this summer, according to research by Northeastern University professor Andrew Sum.

That's largely because kids are facing stiffer competition from older adults, single moms, college grads and new immigrants, all of whom are vying for jobs once seen as largely teens' domain.

"It's an employers' market," said Angela Traiforos, executive director of the Community Learning Center in Fort Worth. "They're looking for people with experience."

At Six Flags Over Texas -- a favorite for teens in search of a job -- youngsters are competing more with adults lately, Human Resources Director Marian Buehler said.

"We have targeted the second wage earners, the moms and the seniors the last few years," Buehler said.

"We're seeing more folks that want or need a second job."

Still, the company has plenty of jobs for teens with a customer-friendly attitude, Buehler said.

"Mainly, we're just looking for people that have customer-service skills, that will make good eye contact, that are polite," she said.

Sum, who last month appeared before Congress to push for a job-stimulus program for young adults, said teen employment has fallen across sexes, ethnicities and incomes.

Nonetheless, black and Hispanic teens from low-income families have fared worst, and boys are less likely to work than girls.

Traiforos said job prospects are particularly challenging for young people who want to dive into permanent, full-time careers instead of studying at a four-year university.

Although most high-school graduates go on to college, roughly a third forgo higher education each fall, according to the U.S. Bureau of Labor Statistics.

Traiforos recommends getting into a hands-on training program or attending courses to develop skills that can help teens stand out.

"The market is just so tight," she said. "Whoever is out there looking for a job needs to have as many certifications as they possibly can get."