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spotted sandpiper

Actitis macularius

What do they look like?

Spotted sandpipers are medium-sized sandpipers. They are 10 to 18 cm long and have wingspans of 37 to 40 cm. Females are larger than males; they weigh 43 to 50 g compared to 34 to 41 g for males. Spotted sandpipers are brown on their crown, neck, back and wings, and bright white on their face, throat, chest and belly. They are called spotted sandpipers because they have black spots on their white undersides. Females usually have larger spots than males. In flight, spotted sandpipers have a white stripe on their wings. (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

Where do they live?

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)

What kind of habitat do they need?

Spotted sandpipers breed in a variety of habitats from sea level to 4,700 m elevation. Females usually defend a breeding territory that includes a shoreline, a partly open area for nesting and patches of dense vegetation. These territories may be found in grasslands, forests, fields, lawns and parks and other habitats.

During spring and fall migrations, spotted sandpipers prefer freshwater habitats, such as lakes, rivers and marshes. However, they also use coasts and estuaries. In winter, spotted sandpipers can be found nearly anywhere that there is water. (Oring, et al., 1997)

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

How do they grow?

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)

How do they reproduce?

Spotted sandpipers are polyandrous (one female mates with several males). Females spotted sandpipers may have 1 to 4 or more mates each season. Females begin each season with one mate. However, as more males arrive, the females compete to attract additional mates. When females have several mates, they do not do much parental care. Instead, the males do most of the work of incubating the eggs and raising the chicks. (Hays, 1972; Oring, et al., 1997)

Spotted sandpipers breed between May and August. Females arrive first in the spring, and establish a breeding territory. The males arrive about 4 days later. The females try to attract a male mate. Once a male and female have formed a breeding pair, they build a nest together in the female's territory. The nests are just a shallow bowl-shape scraped out of the ground and padded with weeds and stems. They are usually built near water.

The female lays a clutch of 4 eggs (sometimes 3). Each female may lay up to 5 clutches per year. The eggs are incubated for 19 to 22 days (average 21 days). The male does most of the incubating, but the female may help. The chicks are well-developed when they hatch. They are able to walk just four hours after hatching, and are able to feed themselves soon after that. The male broods the chicks for a few days after hatching to protect them and keep them warm. The young sandpipers stay with their parents for at least 4 weeks. After they become independent, the young sandpipers join flocks with other spotted sandpipers. Spotted sandpipers usually begin breeding when they are about 1 year old. (Cialdini and Orians, 1944; Klekowski and Klekowski, 1997; Oring, et al., 1997)

  • How often does reproduction occur?
    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 do most of the work to incubate the eggs and raise the chicks. (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

How long do they live?

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

How do they behave?

Spotted sandpipers are diurnal (active during the day). During the day, spotted sandpipers spend some of their time maintaining their bodies. This includes preening their feathers, scratching their heads, stretching, and bathing.

Spotted sandpipers are migratory. The only spotted sandpipers that don't migrate in the fall and spring are the populations that breed and winter along the west coast of the United States and in some parts of California. Spotted sandpipers migrate during the day and at night. Most shorebirds migrate in large flocks, but spotted sandpipers migrate alone or in small groups.

Spotted sandpipers are territorial. During the breeding season, males defend a smaller territory within their female mate's territory. Spotted sandpipers defend their territories aggressively. They fight by pecking at the head and eyes of an intruder and using their legs, wings and bills to fight.

Spotted sandpipers move around by walking, hopping, climbing, and flying. When walking, spotted sandpipers bob up-and-down. They fly with very fast wingbeats. Spotted sandpipers also sometimes 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)

How do they communicate with each other?

Spotted sandpipers use calls and body signals communicate. The calls of spotted sandpipers are all made up of a note that sounds like weet. This note can be repeated at different volumes and speeds to communicate different messages. For example, it can be used to show alarm, to attract a mate or to try to distract predators that come near the nest. (Oring, et al., 1997)

What do they eat?

Spotted sandpipers are carnivores. They eat nearly all animals that they find that are small enough for them to eat. Some of the foods they eat are midges, fish, mayflies, flies, grasshoppers, crickets, beetles, worms, caterpillars, mollusks, crustaceans, spiders, and dead fish.

Spotted sandpipers search for food on the ground. They capture most prey by catching it in their bill. They also catch food by pecking the ground, hopping to catch flying insects, and picking insects off of vegetation. Spotted sandpipers eat more during the breeding season so that they have enough energy for breeding activities. (Oring, et al., 1997)

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

What eats them and how do they avoid being eaten?

Spotted sandpiper eggs are eaten by deer mice, mink, weasels, river otters, yellow-headed blackbirds, red-winged blackbirds, song sparrows and ruddy turnstones. Spotted sandpiper chicks are hunted by common grackles, American crows, gulls and mink. Adult spotted sandpipers are hunted by least weasels, short-tailed weasels and raptors.

When predators approach spotted sandpipers, the sandpipers perform a display to threaten the predator. They hold their body upright and their bill forward. Then they hold their wings out and up, puff out their breast feathers, open their bill and fan their tail. Nesting spotted sandpipers may also pretend to be injured when predators come near their nest. They act like their wing is broken and move away from their nest in order to distract the predator from the nest. This is called the Broken Wing Display. (Oring, et al., 1997)

What roles do they have in the ecosystem?

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

Do they cause problems?

We do not know of any way that spotted sandpipers harm people.

How do they interact with us?

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

Are they endangered?

Spotted sandpipers are pretty common and have a large range. There are about 250,000 spotted sandpipers in the world. Spotted sandpipers are not threatened or endangered. 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.

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.

 
University of Michigan Museum of ZoologyNational Science Foundation

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Moore, K. 2002. "Actitis macularius" (On-line), Animal Diversity Web. Accessed December 21, 2014 at http://www.biokids.umich.edu/accounts/Actitis_macularius/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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