Actitis maculariusspotted sandpiper

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Geographic Range

Spotted sandpipers (Actitis macularius) are found throughout North and Central America, including the western Caribbean islands. Their breeding range extends from the northern Arctic to the southern United States. Their wintering grounds range from the extreme southern United States to southern South America, along with all the Caribbean islands. Spotted sandpipers live year-round along the western coast of the United States and in parts of California. They are found in very small numbers across parts of Europe, Russia, Siberia and on Canton and Marshall Islands in the Pacific Ocean. (Oring, et al., 1997)

Habitat

Spotted sandpipers breed in a variety of habitats ranging in elevation from sea level to 4,700 m. Females typically defend a breeding territory that includes a shoreline (of a stream or lake, for example), a semi-open area for nesting and patches of dense vegetation. These territories may be found in sage-brush, grasslands, forests, fields, lawns and parks among other habitats.

During spring and fall migrations, spotted sandpipers prefer freshwater habitats, such as lakes, rivers and marshes, though they can also be found along the coasts and in estuaries. In winter, spotted sandpipers can be found in coastal and interior areas, nearly anywhere where water is present. (Oring, et al., 1997)

  • Range elevation
    0 to 4,700 m
    0.00 to ft

Physical Description

Spotted sandpipers are medium-sized sandpipers, 10 to 18 cm long with wingspans of 37 to 40 cm. Females are 20 to 25% larger than males, weighing 43 to 50 g compared to 34 to 41 g for males. Spotted sandpipers are brown to olive gray on their crown, nape, back and wings, and bright white on their face, throat, chest and belly. Their common name derives from the bold black spots on their white undersides. Females tend to have larger spots that extend lower on the belly compared to males. While in flight, spotted sandpipers display a white wing-stripe and a plain rump and tail. (Oring, et al., 1997)

  • Sexual Dimorphism
  • female larger
  • sexes colored or patterned differently
  • Range mass
    34 to 50 g
    1.20 to 1.76 oz
  • Range length
    10 to 18 cm
    3.94 to 7.09 in
  • Range wingspan
    37 to 40 cm
    14.57 to 15.75 in

Development

The eggs of this species weigh about 9.6 g and take about 21 days for incubation, with the time decreasing as the season progresses. When they hatch, A. macularius are covered with down and weigh about 6.0 g. Within the first day, they are walking, eating and stretching their wings. Hunting for immobile food starts at 1-2 days, and stalking moving prey begins at 3-5 days. Actitis macularius chicks are brought up mostly by the male, and feed themselves. At about 11 days, chicks start to lift off the ground. At about 15 days, chicks show weak flight, and at about 18 days, chicks can completely lift themselves off the ground and fly a significant distance. Actitis macularius begin breeding at 1 year. (Maxson and Oring, 1980; Oring, et al., 1997)

Reproduction

Spotted sandpipers are polyandrous. Females of this species may mate with upwards of 4 mates each year. Females may begin with one mate with whom they share parental responsibilities. As additional males arrive, females compete for additional mates, leaving the males to perform the majority of parental care. (Hays, 1972; Oring, et al., 1997)

Spotted sandpipers breed between May and August. Females establish a breeding territory about 4 days before males begin arriving. They then court a mate, and the pair builds a nest together. The nests are built in the ground and consist of weeds or stems padding a shallow depression in the dirt. They are typically located in marshes, on coastlines, and near other water sources. The female then lays a clutch of 4 eggs (occasionally 3). Each female may lay up to 5 clutches per year. The eggs are incubated for 19 to 22 days (average 21 days) by the male and by the female to a lesser extent. The chicks are precocial; they are able to walk within four hours of hatching and are able to feed themselves soon thereafter. They are brooded primarily by the male for the first several days after hatching. The young sandpipers remain with their parent(s) for at least 4 weeks after hatching. After becoming independent, the young sandpipers join post-breeding flocks. These sandpipers will be able to breed the next summer when they are about 1 year old. (Cialdini and Orians, 1944; Klekowski and Klekowski, 1997; Oring, et al., 1997)

  • Breeding interval
    Female spotted sandpipers can lay up to 5 clutches per breeding season.
  • Breeding season
    Spotted sandpipers breed between May and August.
  • Range eggs per season
    20 (high)
  • Average eggs per season
    20
  • Range time to hatching
    19 to 22 days
  • Average time to hatching
    21 days
  • Range fledging age
    1 to 24 hours
  • Range time to independence
    4 (low) weeks
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Male spotted sandpipers provide the majority of parental care. Females contribute in varying amounts to nest building, incubation and raising the chicks during the fledgling stage. (Oring, et al., 1997)

  • Parental Investment
  • precocial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • male
      • female
  • pre-weaning/fledging
    • protecting
      • male
      • female
  • pre-independence
    • protecting
      • male
      • female

Lifespan/Longevity

The oldest known spotted sandpiper lived at least 12 years. Most do not live nearly that long. (Oring, et al., 1997)

Behavior

Spotted sandpipers are diurnal. They can sleep anytime, day or night, but generally sleep whenever it is dark. During the day, spotted sandpipers spend some time on self-maintenance, which involves preening, head scratching, stretching, and bathing.

Spotted sandpipers are fully migratory, with the exception of populations that breed and winter along the west coast of the United States and in some areas in California. Spotted sandpipers migrate during the day and at night. Unlike most shorebirds, they migrate singly or in small groups.

Spotted sandpipers are territorial during the breeding season and in winter. During the breeding season, males and females independently defend territories. For monogamous breeding pairs, the male and female territories are essentially identical. For polyandrous females, the males' territories are subsets within the female's territory. Spotted sandpipers defend their territories aggressively. Territorial disputes typically involve pecking at the head and eyes of the opponent while trying to mount their back, and using the legs, wings and bills to fight.

Spotted sandpipers employ walking, hopping, climbing, and flying as means of locomotion. When walking, the birds exhibit a characteristic up-and-down bobbing motion. They fly with shallow, rapid wingbeats. Spotted sandpipers also occasionally swim and dive for prey. (Oring, et al., 1997)

  • Range territory size
    28 to 20000 m^2

Home Range

The home range of spotted sandpipers is not known. (Oring, et al., 1997)

Communication and Perception

Spotted sandpipers use vocalizations and physical displays to communicate. The calls of spotted sandpipers are largely variations on a weet note, that is repeated at different pitches, intensities and rates to communicate different messages. Vocalizations can be used to communicate alarm, to maintain contact with chicks, in courtship, and to distract predators from one's nest. Physical displays are used to threaten others, to solicit a mate and to show submission, among other purposes. (Oring, et al., 1997)

Food Habits

Spotted sandpipers are opportunistic carnivores. They eat nearly all animals that are small enough for them to eat, with the exception of toad tadpoles. Examples of commonly eaten foods include midges, fish, mayflies, flies, grasshoppers, crickets, beetles, worms, caterpillars, mollusks, crustaceans, spiders, and carrion.

Spotted sandpipers forage on the ground. They capture most prey by thrusting their head forward and catching the prey in their bill. They also catch prey by pecking the ground, hopping to catch flying insects, and picking insects off of vegetation. Often, spotted sandpipers will dip insects in water before eating them, although the reason for this is unclear. Spotted sandpipers are visual hunters, mainly using sight to catch prey. When breeding, females increase their food intake to offset the energy spent producing eggs. While incubating, males increase their time dedicated to finding and catching prey by 44.9%. (Oring, et al., 1997)

  • Animal Foods
  • amphibians
  • fish
  • carrion
  • insects
  • terrestrial non-insect arthropods
  • mollusks
  • terrestrial worms

Predation

Spotted sandpiper eggs are vulnerable to predation by predators such as deer mice, mink, weasels, river otters, yellow-headed blackbirds, red-winged blackbirds, song sparrows and ruddy turnstones. Chicks are predated by common grackles, American crows, gulls and mink. Adult spotted sandpipers are taken by least weasels, short-tailed weasels and a variety of raptors.

When threatened, spotted sandpipers perform a display by positioning their body upright and their bill forward. They extend their wings outward and upward, raise their breast feathers, open their bill and fan their tail. Nesting spotted sandpipers may also fake an injury, known as the Broken Wing Display in order to draw predators away from their nest. The Broken Wing Display is performed by crawling low to the ground with the wings flapping on the ground and the tail spread and lowered while squealing. (Oring, et al., 1997)

Ecosystem Roles

Spotted sandpipers affect the populations of the species they eat. They also provide food for their predators.

Economic Importance for Humans: Positive

Spotted sandpipers eat a wide variety of insects. It is possible that they help control insects that humans view as pests.

Economic Importance for Humans: Negative

There are no known adverse effects of spotted sandpipers on humans.

Conservation Status

Spotted sandpipers are common and widespread. Global population estimates appear to be stable at about 250,000 individuals. Threats to spotted sandpipers include pesticide poisoning, hunting and injury and foot loss due to leg-banding.

Spotted sandpipers are not threatened or endangered. They are listed as a species of "least concern" by the IUCN, and are not listed under any of the CITES appendices. They are, however, protected under the U.S. Migratory Bird Act. (Oring, et al., 1997)

Contributors

Kari Kirschbaum (author, editor), Animal Diversity Web.

Katherine Moore (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

brackish water

areas with salty water, usually in coastal marshes and estuaries.

carnivore

an animal that mainly eats meat

carrion

flesh of dead animals.

chaparral

Found in coastal areas between 30 and 40 degrees latitude, in areas with a Mediterranean climate. Vegetation is dominated by stands of dense, spiny shrubs with tough (hard or waxy) evergreen leaves. May be maintained by periodic fire. In South America it includes the scrub ecotone between forest and paramo.

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

estuarine

an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

freshwater

mainly lives in water that is not salty.

insectivore

An animal that eats mainly insects or spiders.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

marsh

marshes are wetland areas often dominated by grasses and reeds.

migratory

makes seasonal movements between breeding and wintering grounds

molluscivore

eats mollusks, members of Phylum Mollusca

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polar

the regions of the earth that surround the north and south poles, from the north pole to 60 degrees north and from the south pole to 60 degrees south.

polyandrous

Referring to a mating system in which a female mates with several males during one breeding season (compare polygynous).

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

sperm-storing

mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

young precocial

young are relatively well-developed when born

References

Cialdini, R., G. Orians. 1944. Nesting studies of the Spotted Sandpiper. Passenger Pigeon, 6: 79-81.

Hays, H. 1972. Polyandry in the Spotted Sandpiper. Living Bird, 11: 43-57.

Klekowski, E., L. Klekowski. 1997. "Spotted Sandpiper, *Actitis macularia*" (On-line). Accessed April 7, 2002 at http://www.bio.umass.edu/biology/conn.river/spotted.html.

Maxson, S., L. Oring. 1980. Breeding season time and energy budgets of the polyandrous Spotted Sandpiper. Behaviour, 74: 200-263.

Oring, L., E. Gray, J. Reed. 1997. Spotted Sandpiper (Actitis macularia). Pp. 1-32 in A Poole, F Gill, eds. The Birds of North America, Vol. 289. Philadelphia, PA: The Academy of Natural Sciences, and Washington, DC: The American Ornithologists' Union.