A bird is cleaned at the International Bird Rescue in Fairfield, California January 20, 2015. A gooey, unknown material discovered on the eastern shores of San Francisco Bay is clinging to the feathers of birds, and more than 100 birds, mostly species of oceangoing, diving ducks, have died after their feathers were fouled by the viscous substance now undergoing testing at state labs in Sacramento. (Photo by Robert Galbraith/Reuters)

Kale grows at Kajodlingen farm in Gothenburg, Sweden, September 28, 2016. They are doing it on the rooftops, on tower block balconies and even on a disused railway: Swedes have discovered a passion for urban gardening as a way of growing fresh food and getting back in touch with nature. Part of a global movement, an increasing number of Swedish city-dwellers are growing their own in window boxes and allotments or are visiting public gardens built in or on industrial or office spaces. (Photo by Maxim Shemetov/Reuters)

A man sleeps between tombstones in front of his single-room home on a hot night in the Cairo Necropolis, Egypt, October 13, 2015. In the sprawling Cairo Necropolis, known as the City of the Dead, life and death are side by side. Amid a housing crisis in Egypt, and with the population of greater Cairo estimated at about 20 million, people count themselves lucky to have a place to call home in the graveyards that date back hundreds of years. (Photo by Asmaa Waguih/Reuters)

An emu runs to escape an approaching wildfire as it burns near Potero, California, U.S. June 20, 2016. (Photo by Mike Blake/Reuters)

Fire photographer Tod Sudmeier gets hit with flying embers from strong winds at the Solimar brush fire that started early Saturday morning in Ventura County, California December 26, 2015. (Photo by Gene Blevins/Reuters)

A sign advising to pray for rain hangs above an exhibit area at the 47th Annual World Ag Expo in Tulare, February 12, 2014. About a hundred years ago, when urban water systems were being developed throughout the state, the city of Sacramento wrote protections from metering into its charter, vowing that residents would always have the right to use as much water as they needed. But on Tuesday, the state's top water regulators released a framework for enforcing California's first statewide mandatory restrictions on urban water use – cuts of 25 percent for non-agricultural users ordered last week by Democratic Governor Jerry Brown as a devastating drought enters its fourth year. (Photo by David McNew/Reuters)

A fairy tale and movie-themed gingerbread house creation, featuring a reindeer, made by pastry students of the San Ysidro Adult School Culinary Arts program is pictured during their 9th annual gingerbread house competition in San Ysidro, California December 9, 2014. The students' voting results will be delivered back to their class but the official judging will be performed by chefs and culinary experts during the 9th annual event. (Photo by Mike Blake/Reuters)

A corgi named Jojo crashes while riding a wave in the medium size dog competition during the 10th annual Petco Unleashed surfing dog contest at Imperial Beach, California August 1, 2015. Proceeds raised at the event go to benefit the San Diego Humane Society. (Photo by Mike Blake/Reuters)