Over the years a large population of grey herons have made an unlikely home in urban Amsterdam. Julie Hrudova documents how the birds integrate into city life. Here: Hundreds of herons come to the city during winter to find food and shelter. (Photo by by Julie Hrudova/The Guardian)

The carcass of a yacare caiman lies in the dried-up river bed of the Pilcomayo river in Boqueron, Paraguay, August 14, 2016. In Paraguay, alongside the Pilcomayo River, black vultures flew over a shrinking pond where a group of crocodilian reptiles known as yacare caimans sought refuge. Water from the river, which divides Paraguay and Argentina in the area of the Gran Chaco, was scarce. This is not an uncommon sight in the region of General Diaz, about 700 kilometres (435 miles) northwest of the country's capital Asuncion, where the Pilcomayo's waters form lakes and streams that give life to capybaras, birds and caimans. (Photo by Jorge Adorno/Reuters)

Russians play accordions as they walk near the building of the Federal Security Service (FSB, Soviet KGB successor) in Lubyanskaya Square to mark May Day in Moscow, Russia, Sunday, May 1, 2016. As in Soviet times, about one hundred thousand of cheerful workers paraded across Red Square despite a chilly rain, but instead of red flags with the Communist hammer and sickle, they waved the blue flags of the dominant Kremlin party and the Russian tricolor. (Photo by Alexander Zemlianichenko/AP Photo)

Breath of an Arctic fox by Marco Gaiotti, Italy. Marco was watching this little Arctic fox as it incessantly called another nearby. Gradually he noticed the fox’s wet breath was quickly freezing in the air after each call. It was late winter in Spitsbergen, Svalbard, and the air was -35C (-31F). Photographing Arctic foxes is often frustrating, as they are normally running around fast in search of food, but this one was very relaxed and let Marco get close enough to focus on it, with the light glowing perfectly in the background. (Photo by Marco Gaiotti/Wildlife Photographer of the Year 2021)

“Double head vulture”. On the day of windy days during raptors migration some people in my country start to catch these tired raptors, so in this day we go to photograph some raptors and we saw these tow tired vultures, so we start to drag them away from the hunters until they reach a good hidden place, to make them safe until they start a new journey. Photo location: Kuwait. (Photo and caption by Mohd Khorshed/National Geographic Photo Contest)

A boy looks for scrap metal using an improvised magnetic tool near a construction site in New Delhi, India, March 21, 2016. (Photo by Cathal McNaughton/Reuters)

Boys play with a drainage culvert used for flood control in Las Pinas, Metro Manila February 28, 2016. (Photo by Erik De Castro/Reuters)