Getting Cold Feet?
Snowfall in the Lowcountry seems to be a bit of a divider. Natives mostly welcome the white stuff, while other residents, who may have moved here partly to get rid of snow and ice, seem to view frozen precipitation a little less fondly.
As the Nature Notes guy, this writer can’t help but wonder how the local wildlife feels about our occasional snow and cold.
Jenny, my wife, and I try to make a nightly lap around Smythe Lake after dinner. These walks range from pleasant spring or fall strolls to summertime mosquito-swatting fests to bundled-up winter walks. One particular daytime jaunt after the major snowfall we had last January is permanently etched in my mind.
As we approached the northwest corner of Smythe Lake, dozens of snowy egrets, along with great egrets, Canada geese, cormorants, seagulls, ducks, and other birds, were all gathered on the lake and along the edge of the water.
Many of our smaller ponds were likely experiencing at least some skim ice, making them more difficult to feed in. There was a lot of feeding activity out in the water, too, and I wondered if some of the small fish were easier to catch with the sharply colder water temperatures hampering their ability to flee.
But my primary thought as I watched the birds on, in, and around the water was that they were probably very cold!
The snowy egret, Egretta thula, might have a wintry-sounding name, but it is not a winter-loving bird. The name comes from their snowy-white feathers. These egrets typically spend January on the southern Atlantic and Pacific coasts of the United States, along our Gulf Coast in Florida, throughout the Caribbean, or in Central and South America.
For the hardy birds that do stay in the northern parts of their range, occasional winter surprises are inevitable. Fortunately, Mother Nature has provided some adaptations for such cold-weather encounters.
Snowy egrets generally wade when they feed. They can often be found in the shallows, agitating the bottom with their feet to spook small fish or stir up other prey. But if wading in the shallows is not an option, the birds can shift into different foraging modes. Egrets can float briefly, swim (although without webbed feet, they aren’t superb swimmers like cormorants or ducks), grab prey from under the surface, and even snatch a fish from the water while hovering.
As for standing in frigid water, snow, or air, another natural tool aids them in staying warm. Egrets have what is known as counter-current blood circulation in their legs.
Veins and arteries immediately next to each other act as heat exchangers, allowing warm blood headed down to cold extremities to help prewarm the cold blood headed back up to the birds’ bodies.
Lastly, egrets can puff out their feathers in cold temperatures, creating pockets of air that help insulate against the cold.
So while the snowy egret may not prefer the cold or snow, it is capable of dealing with them. But like many of their human admirers, the majority of these beautiful birds prefer to spend the winter “chilling” on some tropical beach rather than figuring out how to stay warm while living with snow and ice.