Great Blue Heron in Winter

Assateague Island National Seashore 

Image location: Sinepuxent Bay, Assateague Island National Seashore, Maryland 

Great Blue Herons are one of the few birds we are lucky enough to see in our marshes year-round. Ever wonder why?

Their secret to wading through ice-cold winter waters is in their long, thin legs. Arteries on the inside of the leg carry warm blood down to the feet, while veins run parallel that carry cold blood back up to the body. The process is called countercurrent exchange, and the heat from the arteries serves to warm the chilled blood before it re-enters the body. A pretty neat trick!