San Diego saw a 45% increase in reported bike thefts in the first half of this year from a year earlier. The police station covering the central part of downtown Los Angeles has seen a 72% increase in stolen-bike reports so far this year, the city's police department says. Austin and Philadelphia have seen increases for the past two years. The incidence of theft is likely even higher, cycling advocates say, because many victims don't bother reporting bike thefts.

The reasons for the theft boom are complex, including population growth in some locales, but generally, more people are biking these days—and they are riding pricier bicycles. Also, the economic downturn is contributing to the increase.

"Harder times mean more thefts," says Bryan Hance, founder of StolenBicycleRegistry.com, where people can list their stolen bikes free. Last month, the site received 335 listings, about twice as many as a year ago. "Bikes are a lot more expensive than they were five or 10 years ago," he adds. "The fact that they are worth more makes them more of a target."

And, unfortunately, Heather's story doesn't have a happy ending:

Ms. McKibbon, who recovered her bike in Toronto, also faced new problems. Last weekend, her bike's rims, gears and other components were stolen on a busy street in Toronto.

But she has a message for bike thieves: Watch your back. "The world isn't as big as it once was," she says. "You never know who's watching."

Have you recently had your bicycle stolen? Post your details in the Biking Toronto Stolen Bike Listing

Photo by random dude on Flickr