SHOREBIRDS
Joanna Burger
Department of Cell Biology and Neurosciences,
Ecology, Evolution and Natural Resources, Department of
Marine and Coastal Sciences, Environmental and
Occupational Health Sciences Institute, Rutgers
University, Piscataway, NJ, USA
Synonyms
Sandpipers; Waders
Definitions
Shorebirds are small- to medium-sized birds that often
feed along shorelines, and they breed in a wide range of
habitats near water. They include snipes, godwits, stints,
sandpipers, phalaropes, jacanas, thick-knees, oystercatchers, avocets, plovers, and lapwings.
Sandpipers are a group of small familiar shorebirds that
often move along the shoreline, foraging by running in
and out of the tide.
Waders, another name for shorebirds that is used in
Europe, are also called short-legged waders (herons and
egrets are long-legged waders).
Introduction
Shorebirds are small- to medium-sized birds that frequently
feed along shorelines, often following the waves in and out,
picking up prey from the sand. They include snipes, godwits, stints, sandpipers, phalaropes, jacanas, thick-knees,
oystercatchers, avocets, plovers, and lapwings. Shorebirds
are in 13 families of birds, usually considered in the order
Charadriiformes, which also contains gulls, terns, skimmers, and auks (Warnock et al., 2001). Although “shore”
is part of their name, they are not generally considered
marine birds or seabirds because they do not spend
a significant part of their life cycle at sea (Burger, 1984).
Phalaropes are the exception; they breed in the prairie pothole region of North American and in the Arctic, migrate
to the open ocean, and generally overwinter there before
they return to their breeding grounds. Other shorebirds do
not wander far offshore, except to pass over the ocean during migration. However, 58 % of shorebirds use marine
habitats at some time in their life cycle, and 39 % sometimes or always nest along the coast (Burger, 1984).
Because shorebirds travel over large regions of the world
during their annual cycle, use a full range of habitats in
many biomes and climate zones, and nest in many different
habitats, they are ideal sentinels or bioindicators of global
environmental change (Piersma and Lindstrom, 2004).
Life history
Shorebirds have intermediate life spans, breed when they
are 2–4 years old, usually lay four eggs, have intermediate
incubation periods (3–4 weeks), raise one or more chicks
a year, and have short parental care periods of less than
a month. They have low fecundity, delayed maturity, and
high annual survival. In most species, the young are precocial, meaning that they are covered with down upon hatching, and once they dry off, they are able to move about and
find their own food, although their parents still guard them
until they fledge. The length of the breeding cycle depends
somewhat upon where they breed. Species that breed in
harsh Arctic environments must have a short period to
breed and usually make only one breeding attempt. Species that breed in temperate regions have an extended
breeding period and can attempt second broods.
Shorebirds exhibit a range of breeding patterns, from
monogamy to polygyny (one male with more than one
female mate) and polyandry (one female with more than
one male mate; phalaropes). In some species, all three
patterns can be exhibited, depending upon food resources.
Most shorebirds are territorial when breeding and gregarious when not breeding, often forming large flocks to forage, migrate, and overwinter. Shorebirds have some of the
longest migration routes of all birds, with some species
breeding in the Arctic and wintering at the southern tip
of South America.
Behavior and habitat selection
Breeding
Most shorebirds breed solitarily, although a very few nest
in small colonies (e.g., stilts). While nesting, shorebirds
rely on their cryptic coloration and hide their nests to
avoid mammalian predators. They usually nest on the
ground, in the open sand, under vegetation, on rocky
beaches, or in wet swales from the Arctic to Antarctica,
although some species nest in wet marshes (e.g., snipes),
build floating nests in marshes (e.g., jacanas), or nest in
sand or salt flats. A very few species, such as the Solitary
Sandpiper, Tringa solitaria, nest in trees.
Many species are monogamous, maintaining the same
mate from year to year, and both members of the pair
incubate and care for young. At least 25 species are
polygynous, including some sandpipers, snipes, and
woodcocks. In a few species, such as Ruff (Philomachus
pugnax; Van Rhjn, 1991), males gather at a lek (small display and dancing ground) and display to females. The
females then go off and breed on their own, incubating
without the help of a male. Polyandry occurs in fewer species, perhaps because it is more difficult for the female to
lay a complete clutch for different males than it is for
a male to fertilize the clutches of several females.
Typically, shorebirds make a nest scrap in the ground and
line it with pebbles, shells, grass, or leaves. They lay 1–4
eggs that are pyriform (one end large and rounded, the other
small and V shaped) which allows the four eggs to fit nicely
together with the four small ends toward the center. Clutch
size is a result of their ability to produce the clutch, incubation limitations, and limitations on caring for the young,
such as time constraints on high Arctic species because of
the short Arctic summer (Colwell, 2010). Both parents
incubate, and when the chicks hatch, they leave the nest
SHOREBIRDS
585
Joanna Burger
Department of Cell Biology and Neurosciences,
Ecology, Evolution and Natural Resources, Department of
Marine and Coastal Sciences, Environmental and
Occupational Health Sciences Institute, Rutgers
University, Piscataway, NJ, USA
Synonyms
Sandpipers; Waders
Definitions
Shorebirds are small- to medium-sized birds that often
feed along shorelines, and they breed in a wide range of
habitats near water. They include snipes, godwits, stints,
sandpipers, phalaropes, jacanas, thick-knees, oystercatchers, avocets, plovers, and lapwings.
Sandpipers are a group of small familiar shorebirds that
often move along the shoreline, foraging by running in
and out of the tide.
Waders, another name for shorebirds that is used in
Europe, are also called short-legged waders (herons and
egrets are long-legged waders).
Introduction
Shorebirds are small- to medium-sized birds that frequently
feed along shorelines, often following the waves in and out,
picking up prey from the sand. They include snipes, godwits, stints, sandpipers, phalaropes, jacanas, thick-knees,
oystercatchers, avocets, plovers, and lapwings. Shorebirds
are in 13 families of birds, usually considered in the order
Charadriiformes, which also contains gulls, terns, skimmers, and auks (Warnock et al., 2001). Although “shore”
is part of their name, they are not generally considered
marine birds or seabirds because they do not spend
a significant part of their life cycle at sea (Burger, 1984).
Phalaropes are the exception; they breed in the prairie pothole region of North American and in the Arctic, migrate
to the open ocean, and generally overwinter there before
they return to their breeding grounds. Other shorebirds do
not wander far offshore, except to pass over the ocean during migration. However, 58 % of shorebirds use marine
habitats at some time in their life cycle, and 39 % sometimes or always nest along the coast (Burger, 1984).
Because shorebirds travel over large regions of the world
during their annual cycle, use a full range of habitats in
many biomes and climate zones, and nest in many different
habitats, they are ideal sentinels or bioindicators of global
environmental change (Piersma and Lindstrom, 2004).
Life history
Shorebirds have intermediate life spans, breed when they
are 2–4 years old, usually lay four eggs, have intermediate
incubation periods (3–4 weeks), raise one or more chicks
a year, and have short parental care periods of less than
a month. They have low fecundity, delayed maturity, and
high annual survival. In most species, the young are precocial, meaning that they are covered with down upon hatching, and once they dry off, they are able to move about and
find their own food, although their parents still guard them
until they fledge. The length of the breeding cycle depends
somewhat upon where they breed. Species that breed in
harsh Arctic environments must have a short period to
breed and usually make only one breeding attempt. Species that breed in temperate regions have an extended
breeding period and can attempt second broods.
Shorebirds exhibit a range of breeding patterns, from
monogamy to polygyny (one male with more than one
female mate) and polyandry (one female with more than
one male mate; phalaropes). In some species, all three
patterns can be exhibited, depending upon food resources.
Most shorebirds are territorial when breeding and gregarious when not breeding, often forming large flocks to forage, migrate, and overwinter. Shorebirds have some of the
longest migration routes of all birds, with some species
breeding in the Arctic and wintering at the southern tip
of South America.
Behavior and habitat selection
Breeding
Most shorebirds breed solitarily, although a very few nest
in small colonies (e.g., stilts). While nesting, shorebirds
rely on their cryptic coloration and hide their nests to
avoid mammalian predators. They usually nest on the
ground, in the open sand, under vegetation, on rocky
beaches, or in wet swales from the Arctic to Antarctica,
although some species nest in wet marshes (e.g., snipes),
build floating nests in marshes (e.g., jacanas), or nest in
sand or salt flats. A very few species, such as the Solitary
Sandpiper, Tringa solitaria, nest in trees.
Many species are monogamous, maintaining the same
mate from year to year, and both members of the pair
incubate and care for young. At least 25 species are
polygynous, including some sandpipers, snipes, and
woodcocks. In a few species, such as Ruff (Philomachus
pugnax; Van Rhjn, 1991), males gather at a lek (small display and dancing ground) and display to females. The
females then go off and breed on their own, incubating
without the help of a male. Polyandry occurs in fewer species, perhaps because it is more difficult for the female to
lay a complete clutch for different males than it is for
a male to fertilize the clutches of several females.
Typically, shorebirds make a nest scrap in the ground and
line it with pebbles, shells, grass, or leaves. They lay 1–4
eggs that are pyriform (one end large and rounded, the other
small and V shaped) which allows the four eggs to fit nicely
together with the four small ends toward the center. Clutch
size is a result of their ability to produce the clutch, incubation limitations, and limitations on caring for the young,
such as time constraints on high Arctic species because of
the short Arctic summer (Colwell, 2010). Both parents
incubate, and when the chicks hatch, they leave the nest
SHOREBIRDS
585