surface, but they probe for sand crabs and chase small fish
and fiddler crabs as well.
Short Bills
Plovers are examples of shorebirds with short bills. Both large
and small plovers have short, pointed, stout bills and large
eyes. These birds are known for their quick sprints, abrupt
stops, pecking, and then they are off again—locating prey
by sight on the surface along the water’s edge or in damp
areas even feeding sometimes at night under a full moon. A
number of plover species will “foot-stir” to liquefy sediments
as mentioned above. Plovers feed on crustaceans, worms,
insects, and mollusks.
Some other unique feeding habits of shorebirds can be
seen in oystercatchers, skimmers, and ruddy turnstones.
Oystercatchers are large, easily recognized birds with red-to-
orange bills and a red ring around yellow eyes. Their flat bills,
shaped like a double-edged knife, are used to open shellfish
and pry other prey such as limpets from rocks. The tip of the
bill can slip into a clam or oyster to cut the adductor muscles.
If the prey is tightly closed the bird will hammer a hole in the
shell with its bill to get the soft bodies inside. Interestingly,
oystercatchers will feed on crabs, jellyfish, marine worms,
starfish, sea urchins, and other invertebrates. These shorebirds
are great parents who may take six months to a year to train
offspring in their specialized feeding techniques.
Black skimmers can feed day and night by touch using
their sharp, thin, red and black bills to skim the water’s
surface dragging their lower (and longer) bills (called
mandibles) through the water. The bill will immediately snap
shut when it captures small fish, crustaceans, mollusks, and
insects.
Ruddy turnstones are amazing little birds with red legs and
short, slender, straight-to-slightly-upturned bills that are used
to turn over shells, pebbles, and other items on the beach
or rocky shores looking for a great variety of food. These
shorebirds seem to always be in a hurry. They are known
to consume bivalves, small crabs, snails, limpets, barnacles,
marine worms, shrimp, sea slugs, sand fleas, horseshoe crab
eggs, seeds, berries, and carrion (such as rotting fish). Ruddy
SUMMER/FALL 2017 • VOLUME 38
turnstones also eat other birds’ eggs and a variety of insects
(and their larvae) such as grasshoppers and flies. They are
opportunistic feeders and have even been seen foraging
behind people who are eating popcorn and French fries.
And Yes, They Eat Slime
If you walk along the beach or marsh, you might see or feel
a layer of slime covering the surface of the mud or water
close to the edge. This nutritious slime, called “biofilm,” is a
valuable and substantial food source for migrating species
providing energy-rich carbohydrates and proteins that
can’t be obtained from other foods such as crustaceans and
invertebrates. Plovers, sandpipers, and other shorebirds
consume this biofilm that is made up of a collection
or “matrix” of microorganisms including bacteria and
microalgae, and also organic detritus.
A Cautionary Tale
Unique bills, leg structures, and, therefore feeding behaviors,
ensure that food will be available to the great variety of
shorebird species living in wetlands and intertidal zones,
but research has shown that shoreline modification projects
and human disturbances can reduce foraging success. The
South Carolina Department of Natural Resources reports that
physical changes resulting from beach re-nourishment may
be associated with changes in macroinvertebrate distributions
and subsequent disruption of biological characteristics
of these vital areas thus impacting migratory and other
shorebird populations. NK
21