In this undated photo made available by journal Nature on January 15, 2014, a northern bald ibis (Geronticus eremita) flies in Tuscany, Italy. A new study released Wednesday, January 15, 2014 says the birds choreograph the flapping of their wings, getting a boost from an updraft of air in the wake of the flapping wings by flying behind the first bird and off to the side. When a flock of birds take advantage of these aerodynamics, they form a V. (Photo by Markus Unsöld/AP Photo)

Animal rights activists covered with fake blood sit on the floor during a protest against the use of animals in research to mark World Day for Animals in Laboratories in central Madrid April 24, 2014. The sign reads, “How many rabbits do your shampoo kill?”. (Photo by Andrea Comas/Reuters)

Spectators cheer as the United Launch Alliance Delta 4-Heavy rocket, with NASA's Orion spacecraft mounted atop, lifts off from the Air Force Station, December 5, 2014, in Cape Canaveral, Fla. (Photo by Smiley N. Pool/AP Photo/Houston Chronicle)

A jogger runs on the bank of Donaukanal channel in central Vienna, Austria, September 5, 2016. (Photo by Heinz-Peter Bader/Reuters)

A woman walks past a stall at a market in Banjul, Gambia December 15, 2016. (Photo by Afolabi Sotunde/Reuters)

Kashir Mir, 34, poses for a photograph at his workplace, Juliet Wig Shop, in the London constituency of Brent Central, Britain, April 13, 2015. Mir, who was born in Pakistan, said: “I will vote but it's a secret. I also hope they can manage immigration better as I have been stopped and interviewed for hours returning from Pakistan. I'm an honest man, working here and paying my tax”. Brent, a northwest London neighbourhood that's home to Wembley football stadium, is among the most ethnically diverse areas in the United Kingdom. As the country approaches a closely fought election on May 7, Reuters photographer Eddie Keogh visited shopkeepers to get their views on the poll. (Photo by Eddie Keogh/Reuters)

A girl walks in front of a graffiti painted on the wall of a house located inside the 15th-century complex built by Mameluk Sultan al-Ashraf Qaitbey, in Cairo's City of the Dead, Egypt February 13, 2017. (Photo by Amr Abdallah Dalsh/Reuters)

A baby elephant eats in a swamp in Amboseli national park, Kenya, March 19, 2017. (Photo by Goran Tomasevic/Reuters)