Rose-ringed Parakeets roost in a copse in Wormwood Scrubs Park on December 6, 2011 in London, England. Approximately 2,500 parakeets roost in the copse at the centre of Wormwood Scrubs which has been designated by English Nature as an important site of natural significance. (Photo by Oli Scarff/Getty Images)

Revelers dressed as Santa Claus drink outside at a bar during the annual SantaCon event December 10, 2011 in New York City. SantaCon is a mass gathering of revelers dressed as Santa Claus who take to the streets in cities across the country before Christmas. (Photo by Allison Joyce/Getty Images)

A Burmese worker sets up Christmas lights inside a woman's clothing store inside a shopping mall December 6, 2011 in Nay Pyi Taw, Myanmar. (Photo by Paula Bronstein/Getty Images)

A Chinese man made up like “Wutu” which means tiger in ancient time, dances during an annual exorcism ceremony of the local Tu ethnic minority group at Nianduhu Village on December 31, 2004 in Tongren County, northwest of China. (Photo by China Photos/Getty Images)

(L-R) Actors Oscar Sinela, Luis Fernandez, Ursula Corbero, Amaia Salamanca, Maxi Iglesias and Alba Ribas attend “XP3D” premiere at the Callao cinema on December 27, 2011 in Madrid, Spain. (Photo by Carlos Alvarez/Getty Images)

Lindsay Heimbach goes airborne while sledding down a hill on Mt. Lemmon December 27, 2008. (Photo by James Gregg/Arizona Daily Star)

A photo made avialable on 05 August 2015 shows an Indian woman collecting drinking water from a water pump in the submerged village of Sreerampur, some 150 kilometers north of Calcutta, India, on 04 August 2015. At least 215 people have died in floods and a landslide following monsoon rains in India over the past week, 83 deaths were reported from the western state of Gujarat and 69 from eastern West Bengal. The worst-affected states were West Bengal, Gujarat and Rajasthan, the Home Ministry said. (Photo by Piyal Adhikary/EPA)

Then U.S. Army First Lieutenant Kirsten Griest (C) and fellow soldiers participate in combatives training during the Ranger Course on Fort Benning, Georgia, in this handout photograph taken on April 20, 2015 and obtained on August 20, 2015. When Griest and another woman completed the daunting U.S. Army Ranger school this week they helped end questions about whether women can serve as combat leaders, as the Pentagon is poised to open new roles, including elite Navy SEALs, to women in coming months. The feat by Griest and First Lieutenant Shaye Haver followed a re-evaluation of the role of women after their frontline involvement in Iraq and Afghanistan and the end of a rule barring them from combat roles in 2013. (Photo by Spc. Nikayla Shodeen/Reuters/U.S. Army)