Slowing wading through a clear tidal pool, about knee deep, in coastal Florida, I was trying to move slow enough to not disturb a gorgeous American Oystercatcher that was napping on a small sandbar in the middle of the lagoon. Oystercatchers are amazing looking shorebirds with a black hood punctuated by a bright yellow eye surrounded by a striking orange ring. Matching the crazy looking eye is a very long, thick, orange to red bill that the bird uses for probing into the sand for aquatic insects.

It has long sturdy legs and when resting they have the habit of tucking one leg up into its belly feathers and slipping their long bill under a wing to conserve warmth. This is a standard resting position for many shorebirds.

I was slowly moving across the shallow lagoon, being careful to watch for alligators and water snakes. Each advancing step needs to be tested to make sure it’s not too deep, not too slippery and I am not stepping on any hidden aquatic critter. In addition when carrying 30K worth of camera gear, the last thing you want to do is slip and drop your camera gear in salt water. That would be a major disaster.

I had the sun at my back and the lighting was perfect. It was just an hour or so before sunset and the harsh light of the mid-day had passed and now the shadows were nice and long making the light soft and warm. The air temperature was in the high 70’s and no wind. Absolutely perfect conditions for this kind of photography work.

As I approached I could see the oystercatcher’s had his long orange bill tucked under his wing and he was sleeping. This got me thinking about shorebirds in general. Studies show that when shorebirds are resting they often gather in small flocks. They collect close together, often standing on one leg which helps them conserve heat.

The birds that are located near the center of the flock will close both eyes and sleep. The birds on the edge of the flock will sleep with one eye close and the other open. In addition the open eye is usually the one pointing outside of the flock to watch for incoming predators.

Birds have the ability “sleep” with one eye closed and one open. It is called unihemispheric, slow-wave sleep (USWS) and allows the birds to see approaching danger/predators while still being able to rest/sleep. If the right eye of the bird is close, the left side of the brain rests. And if the left eye is close the right side of the brain gets a well-deserved break.

This ability to control sleep and wakefulness simultaneously is unique to birds but has also been observed in seals, manatees and dolphins. This allows these aquatic mammals to sleep underwater and still be able to rise to the surface to breathe without having to fully wake up every few minutes.

When approaching the American Oystercatcher, who was all by himself, he quickly saw me coming with his one open eye. He untucked his bill from under his wing to watch me, but he was so comfortable with me that he never put down the leg that he had tucked into his belly feathers. Obviously I wasn’t a threat to him and he remained comfortable, allowing me to capture a few images before I turned and headed back to the other side of the lagoon. While walking back through the water I thought about the amazing adaptions that wildlife employs in their everyday life. These are the aspects of nature that are the least understood but are the things that fascinate me.

It wasn’t until recently that USWS was first observed and studied. This kind of behavior was once thought (sleeping with one eye open) to be impossible but of course nature has been doing it for millions of years. We just hadn’t noticed it and certainly didn’t understand it. Perhaps this another wakeup call (pun intended) for us to learn from mother nature. Until next time…

Stan Tekiela is an author / naturalist and wildlife photographer who travels the world to study and photograph wildlife. He can be followed on www.facebook.com and twitter.com. He can be contacted via his web page at www.naturesmart.com.