Nature Note #177: Simply S(t)unning

For us naturalists, the nature bug never really turns off. We're constantly noticing, watching, listening like an owl waiting for a mouse to make a wrong turn in the grass. Things that most people would walk past fascinate us, drive us mad about not knowing what they are, and implore us to learn more about another piece in nature's puzzle.

The sun over the past few weeks has been unrelenting and hot. The summer heat isn't unexpected for us here in the Northeast, but this extended period without rain has left us with hills of dry grass and crisp leaves. I've never seen the leaves change color in July. Maples and oaks turning orange and brown not from a decrease in light, but instead recoiling from their provider with wilted leaves, rattling in the wind.

Even the Ailanthus that mark the border of many city streets and sidewalks are wilting in the heat, their leaves yellowing as a lack of rain punishes anything green below the sun. Fortunately not all are suffering in the heat.

The other day I managed to see a sunning starling. Now perhaps you read that sentence too quickly and thought;

"A stunning starling?! Why they are hardly stunning at all!"

Based on that fact I would have to disagree with you. They are pretty stunning when considering their impressive winter flocks winding their way through the sky like a plastic bag rolling in the updraft of a garbage truck. Their ability to mimic sounds and words was inspiring for Shakespeare who wrote in Henry IV, Part I;

"I shall have a starling be taught to speak

Nothing but "Mortimer", and give it him

To keep his anger still in motion." 

The word I used instead was sunning, not "stunning". Sunning is simply the act of sitting in the sun and enjoying its properties of heat and light. For ectotherms like snakes and lizards, sunning is necessary for temperature regulation. Without being able to sit in the sun, they wouldn't have the energy to move around to catch food and escape danger. By sitting in the sun, they warm their bodies to the surrounding air temperature and will remain active so long as the temperature around them remains steady. 

The starling I saw isn't an ectotherm, rather it is an endotherm, which is an animal that can maintain a constant body temperature. This includes us humans who have a internal body temperature of 98.6 degrees Fahrenheit, while for a little bird like a starling it is about 104 degrees. Despite having "hotter blood" as it were, this bird wasn't trying to improve its tan. 

According to an article in Scientific American, some possible explanations for sunning is that exposing their skin to the sun helps to kill parasites or allows the bird to relax while contending with the molt. The reasons it seems are about as numerous as the poses birds put themselves in while "sunning". I suspect that this little bird was simply enjoying the sun on a warm day, but even in this heat, I can only imagine it would do this for a short period of time.

As I walked by, it continued to sit, wings and tail spread while a peacock strutted past.

"It's amazing how even at a zoo, you can't help but notice the local wildlife." I thought as I walked inside. 

Fortunately for me, an air conditioned interior awaited, but I was still glad that I was able to pause and contemplate that starling and appreciate how such a simple behavior could inspire such profound thoughts.

It was simply s(t)unning!