“Cassowaries are large, flightless birds related to emus and (more distantly) to ostriches, rheas, and kiwis”, writes Olivia Judson in the September issue of National Geographic magazine. How large? People-size: Adult males stand well over five foot five and top 110 pounds. Females are even taller, and can weigh more than 160 pounds. Dangerous when roused, they’re shy and peaceable when left alone. But even birds this big and tough are prey to habitat loss. The dense New Guinea and Australia rain forests where they live have dwindled. Today cassowaries might number 1,500 to 2,000. And because they help shape those same forests – by moving seeds from one place to another – “if they vanish”, Judson writes, “the structure of the forest would gradually change” too. (Photo by Christian Ziegler/National Geographic)

Scientist Jiri Sindelar checks a ring of a Boreal owl chick outside the “Smart Nest Box”, which allows the study of birds by using mounted cameras, in a forest near the village of Mikulov, Czech Republic, June 18, 2016. (Photo by David W. Cerny/Reuters)

A TV cameraman drives into Usain Bolt of Jamaica after the men's 200m final during the Beijing 2015 IAAF World Championships at the National Stadium, also known as “Bird's Nest”, in Beijing, China, 27 August 2015. Bolt won the race. (Photo by Rolex Dela Pena/EPA)

Tropical acrobatics by Adrià López Baucells in Manaus, Brazil. An unidentified South American marsupial, although the characteristic black markings on its face indicate it may be a mouse opossum. These small creatures are nocturnal and feed on bugs, fruit and bird eggs. (Photo by Adrià López Baucells/2019 Royal Society of Biology Photography Competition)

A kangaroo and joey are seen in a burnt forest on Kangaroo Island, south west of Adelaide on January 16, 2020. Australia’s continuing bushfire crisis has taken an enormous toll on wildlife, with huge numbers of mammals, birds, reptiles, insects and other species killed. (Photo by Jo-Anne McArthur/Weanimals)

A nesting bird peeks out of the budding Japanese Yoshino cherry tree along the Tidal Basin in Washington, Sunday, April 7, 2013. Despite repeated predictions peak blossom time for the historic cherry trees is not yet here, but almost, almost. (Photo by Carolyn Kaster/AP Photo)

Ahmad Sayed Rahman, a five-year-old Afghan boy who lost his right leg when he was hit by a bullet in the crossfire of a battle, dances with his prosthetic leg at the International Committee of the Red Cross (ICRC) hospital for war victims and the disabled, in Kabul on May 7, 2019. (Photo by Wakil Kohsar/AFP Photo)

A Nepalese Gurung community woman, wearing traditional attire, prepares to participate in a parade to mark their New Year known as “Tamu Loshar” in Kathmandu, Nepal, Friday, December 30, 2016. The indigenous Gurungs, also known as Tamu, are celebrating the advent of the year of the bird. (Photo by Niranjan Shrestha/AP Photo)