And then we see them.

Ghostly shapes gathered around small clumps of plants or hills of sand or discarded plastic bottles - any shelter to cut the force of the wind - shorebirds! Shorebirds by the hundreds, where just a few minutes ago we would  have sworn there was nothing but blowing sand!

Hilton Head Island’s beaches serve as home, migration stopover or wintering grounds to numerous species of shorebirds, including the semipalmated plover, black-bellied plover, dunlin, red knot, sanderling, ruddy turnstone, marbled godwit, black skimmer, willet and piping plover.

During low tide, when invertebrate-rich areas of sand and mud are exposed, many of these species can be seen actively feeding (foraging) in these areas. During high tide when these feeding areas are covered by water, these same birds rest (roost) on the beach in groups numbering from a few individuals to many hundreds. They may rest below the high tide line or above it; in strong winds, many can be seen hunkered down on the leeward side of emerging dunes, beach plants or piles of marsh grasses.

Although they may not look like they are doing anything when they rest, they are actually doing something critical to their survival: conserving energy. In general, the smaller an animal is, the faster it burns energy and the more it needs to eat.

Just like humans, birds are warm-blooded, which means that they maintain a constant internal body temperature regardless of the temperature of the environment. Although this allows birds to live in areas of the world that have extreme temperatures, it also requires lots of energy.

The bottom line for shorebirds is that unless they take in more energy than they use for temperature regulation and other activities, and use that energy to build fat stores, they may not survive the rigors of migration or breeding.

One of our many interesting winter shorebirds is the sparrow-sized piping plover. Our beach is host to 15 to 22 pipers, most of which are here on the island from November to April.

Denial and delay

You can be a positive influence on the survival of shorebirds by sharing the beach with them. Here are some ways to help:

• Walk or bike around groups of shorebirds.
• Keep your dog from chasing birds.
• Avoid posted resting areas.
• Learn to recognize birds and their habitat.
• Dispose of your trash properly.
• Teach others to respect our shorebirds.

Some of these birds have been banded with leg bands so that individuals can be recognized. The shape, color, material and combination of the leg bands gives scientists information on such things as what population the bird belongs to, age and where each banded bird spends the winter.

The winter feather colors of the piping plover blend in with beach sand very well, making it hard to see the birds from a distance. They tend to rely on this coloration and lack of movement to avoid attracting predators. This behavior can also work against them on beaches heavily used by humans, however, as it increases their chances of being stepped on or taken by a domestic animal. Piping plover numbers are already very low, and all three populations are considered threatened or endangered.

So, the next time you are on the beach, please remember our shorebirds and the amazing lives they live.

Here are some facts about shorebirds:

• The piping plovers that visit Hilton Head Island are here only in the winter to escape the harsh winters in places like North Dakota, Maine and the Great Lakes region, where they breed and to store up fat for the spring migration and breeding season.
• The Great Lakes population of piping plovers is designated as endangered; the Northern Great Plains and Atlantic Coast populations are threatened.
• The red knot, which is not brownish red but gray during the winter, migrates to Hilton Head from the Arctic, with some birds going as far as Tierra del Fuego at the southern tip of South America, a journey of 9,300 miles.
• Red knots rely on the abundance of horseshoe crab eggs as a major source of energy for migration and breeding. As horseshoe crab populations have declined, so have red knot populations.
• The champion of bird migrants is the Arctic tern, who migrates from its Arctic breeding grounds to its wintering grounds off of Antarctica every year, a trip of about 25,000 miles.
• The more shorebirds are forced to fly by human disturbance, the less energy they can store for migration and raising chicks.

To learn more, visit the Cornell Lab of Ornithology at allaboutbirds.org, or pick up one of the many great field guides available on the Eastern birds of North America.