A bizarre photo captures the moment a secretary bird (Sagittarius serpentarius) closes its third eyelid as it catches a flying grasshopper. The image is one of the winners of the 2024 Royal Society Publishing Photography Competition, held in collaboration with the Royal Photographic Society, and recognizes images depicting hidden scientific phenomena in the natural world.
The secretary bird was captured by biologist and photographer Peter Hudson, who was named the winner of the Ecology and Environmental Sciences category.
“Secretary birds are very similar to hawks, but have evolved a stork-like lifestyle where they fly around savannas and eat grasshoppers, lizards, and amphibians by punching them off the ground,” Hudson said in a statement emailed to Live Science.
“This bird has just caught a grasshopper, and as it swallows its prey, it closes its third eyelid, the nictitating membrane, to protect its eyes from damage.” Secretary birds are large predatory birds — reaching about 4 feet (1.2 meters) in height — with eagle-like bodies and long, crane-like legs. They are native to sub-Saharan Africa and, while they can fly, they spend most of their time moving about in tall grasses looking for food.
Hudson’s image shows the bird’s third eyelid, which looks like a blue ball sitting in the eye socket. According to the National Audubon Society, the third eyelid sits beneath the upper and lower eyelids. It rests on the inside of the eye and moves horizontally across the eyeball to keep it free from dust, wind and hazards — earning the eyelids the nickname “nature’s glasses.”
An aerial image of four sharks hunting a school of fish was declared the overall winner of the competition. It was taken by Angela Albi, a researcher at the Max Planck Institute of Animal Behavior in Germany, who studies interactions between sharks and fish.
“Just after sunrise or before sunset, the shallow waters of the Maldives become a clear, transparent surface,” she said in the statement. “These are also the moments when we are best able to observe the interactions between reef sharks and their prey. In this frame captured during a research trip in 2024, a shark on the far left suddenly changes from swimming calmly within the school to starting to hunt, its body appearing different from the others.
Although we still don’t know what triggers these attacks, we analyze the videos to study how sharks hunt and how their prey react collectively.” The winners in the Astronomy, Earth Science and Microimaging categories can be seen below.