A number of beehives are sitting on top of the W Hotel in San Francisco, on April 18, 2016.
At least seven San Francisco hotels have built rooftop beehives that produce honey for food, cocktails and spa products. Convention and tourist hotels from Union Square to Fisherman's Wharf say they're doing their small part to combat worldwide honeybee colony collapse.
A caution sign is posted near beehives on top of the Clift Hotel in San Francisco on April 18, 2016.
Rooftop beekeeping is the latest in a series of environmental programs at hotels that includes low-flow toilets and aggressive recycling programs.
Beekeeper Spencer Marshall checks a number of hives on a garden deck outside the Fairmont Hotel in San Francisco on April 18, 2016.
Fairmont's first beehives were built in 2008 at the company's hotels in Toronto and in Vancouver in an effort to help combat Colony Collapse Disorder. Since then, dozens have been installed at Fairmonts from Seattle to China and Africa.
Beekeeper Roger Garrison, left, and hotel general manager Michael Pace look over beehives on top of the Clift Hotel in San Francisco on April 18, 2016.
The honey produced at the Clift's is used in the hotel's Peerless Purple drink with gin-infused lavender, honey syrup and lavender bitters, and its compressed watermelon salad with lavender-infused honey and goat cheese.
Roger Garrison holds a container with a queen bee inside on the roof of the W hotel in San Francisco on April 18, 2016.
A new honeycomb-themed tap delivers a honey beer at the Fairmont Hotel in San Francisco on May 4, 2016.
Chef Thomas Weibull drizzles honey over a watermelon salad at the Clift Hotel in San Francisco.
Honey is used as an ingredient to make a 49er Tea Time cocktail in the Redwood Room at the Clift Hotel in San Francisco.