Semipalmated sandpipers (Calidris pusilla) are small shorebirds which breed along the coast of the Hudson Bay and the coast of northern Alaska. During the non-breeding season semipalmated sandpipers migrate to coastal South America, the Caribbean, and Central America. Migration occurs in long flights of 3000 to 4000 kilometers from Canada and the northern United States to South America. The birds travel in large migratory flocks which can vary in size and can be as large as 350,000 individuals. Some semipalmated sandpiper populations follow very specific migration paths with regular stops at critical, resource-rich locations such as the Bay of Fundy in eastern Canada, and the Delaware Bay in the United States. Short flight migration is also prevalent when individuals or flocks move to closer areas. ("The Cornell Lab of Ornithology", 2009; Gough, 2012; Lank, et al., 2003; Page and Middleton, 1972; Peterson, et al., 2009; Shepherd and Boates, 2001; Tsipoura Burger and Burger, 1999; del Hoyo, et al., 1996)
Semipalmated sandpipers breed along the shores of northern Canada and Alaska on wet sedge or sedge-tundra. They select open habitats well-suited for breeding displays and scrape nests. They generally are found running along sandy shorelines, probing the loose sand for invertebrates. Ideal foraging habitat includes pools close to lakes and rivers, shrubby river deltas, and sandy areas along the shore. Migration stopover habitats may include wetlands, grassy fields, marshes, or edges of lakes and rivers. During non-breeding winter months, semipalmated sandpipers inhabit sandy beaches and intertidal zones of South America, the Caribbean, and Central America. ("The Cornell Lab of Ornithology", 2009; del Hoyo, et al., 1996)
Semipalmated sandpipers are small sized shorebird about 13 to 15 cm long weighing from 21 to 32 g. They have black legs and straight tubular bills which are black or darkly colored. Wingspan ranges from 29 to 30 cm. The name 'semipalmated' refers to the slight webbing between the 3 front toes. Plumage differs between juveniles, breeding and nonbreeding adults. During the breeding season semipalmated sandpipers have gray to brown upper body, with a uniformly scaly pattern. The belly is white with darker streaks along the upper breast. Juveniles vary greatly in plumage, but generally have a darker brown cap with a pronounced supercilium. Nonbreeding plumage fades to a lighter gray-brown on the upper body with only faint streaking on sides of an otherwise white breast. On average females are slightly larger than males. ("The Cornell Lab of Ornithology", 2009; Page and Middleton, 1972; Peterson, et al., 2009; del Hoyo, et al., 1996)
Semipalmated sandpipers breed from late May to July. Upon arriving at the breeding grounds, males establish territories from which to display to females arriving about a week later. Males perform aerial displays at 5 to 9 m where they hover and produce "motorboat" calls. These aerial displays are well suited to their relatively open habitat where visibility is high. The male excavates up to 10 to 12 scrapes among sparse vegetation within his territory for females to choose from. The female will then select 2 to 3 of these scrapes (although only one is used) to begin lining with vegetation and other organic matter. Semipalmated sandpipers form monogamous pairs. (del Hoyo, et al., 1996)
Semipalmated sandpipers breed from May through July. After mating, the male defends the territory while the female lays eggs in the nest. Females typically lay 3 to 4 eggs per brood in 24 to 32 hour intervals. Incubation of the eggs, which is done by both parents, lasts 18 to 22 days. Like all scolopacids, semipalmated sandpipers are precocial at birth and begin actively foraging within hours of hatching. The young fledge 16 to 19 days after hatching. Semipalmated sandpipers reach sexual maturity at 1 year old. ("The Cornell Lab of Ornithology", 2009; Hicklin and Gratto-Trevor, 2010; Peterson, et al., 2009; del Hoyo, et al., 1996)
Semipalmated sandpipers provide parental care for their young starting with incubation by both parents. Incubation lasts 20 to 22 days. Both parents participate in feeding and protecting the young for up to 11 days. Between 6 to 11 days after the chicks hatch the parents abandon the brood at separate times with the female being the first to leave nearly 91% of the time. Females stay with their young on average 6 days after they are hatched then leave their young to be provided for by their mate. The male continues to make a night scrape for the young for 6 to 8 days after hatching. The male abandons the brood on average 8 days after female, regardless of whether or not chicks have fledged. (Gratto-Trevor, 1991; del Hoyo, et al., 1996; Gratto-Trevor, 1991; Hicklin and Gratto-Trevor, 2010; del Hoyo, et al., 1996)
Annually it is estimated that 50% to 70% of adult semipalmated sandpipers survive. Some causes of mortality (degree of impact unknown) include illegal poaching on wintering grounds and botulism. It has been noted that juveniles have much lower fat reserves than adults when they arrive at wintering grounds, but how that affects survivorship is unknown. Longest known living individual was a female at 16 years old. The odds of a survival until age of 16 are 1 in 10000 if survival rate is ~50%. (del Hoyo, et al., 1996; Gratto-Trevor and Vacek, 2001; Hicklin and Gratto-Trevor, 2010; del Hoyo, et al., 1996)
Semipalmated sandpipers are migratory shorebirds with a very large range. Many amass to embark on 3000 to 4000 km transatlantic flights from northern Canada to South America. During the nonbreeding season, large flocks cooperate to deter predators such as falcons. In contrast, during the breeding season adults behave in monogamous pairs which defend territory, nest, and young. ("The Cornell Lab of Ornithology", 2009; Gough, 2012; Gratto-Trevor, 1991; Lank, et al., 2003; Page and Middleton, 1972; Peterson, et al., 2009; Shepherd and Boates, 2001; Tsipoura Burger and Burger, 1999; del Hoyo, et al., 1996)
Territory size varies for semipalmated sandpipers. There have been estimates of 1 ha, however some nesting habitats have reported higher densities and thus smaller territories. (Jehl, 2006)
Semipalmated sandpipers use vocal and visual forms of communication. Many calls have been linked specific situations and functions. For example, a soft 'cher' is often made from individuals of a large roosting flock to convey safety or lack of threat. This 'cher' is quickly replaced by a loud 'churt' when predators are detected. Other calls have been described for nest defense, chick defense, injury feigning, copulation, short-range communication between mates, calling chicks, and brooding.
Males use aerial displays to attract mates to established territories. These displays include a "motorboat" call given while hovering in midair.
Semipalmated sandpipers perceive auditory, tactile, visual, and chemical stimuli. (Peterson, et al., 2009)
Semipalmated sandpipers utilize a probing method to forage for small invertebrates on the ground, in mud, or occasionally under water. Typical diet consists of chironomid larvae (Diptera), arachnids, plant seeds, tipulid larvae (Diptera), dolichopodid larvae (Diptera), snails, Donacia adults (Chrysomelidae, Coleoptera), Lispe larvae (Muscidae, Diptera), Agapes larvae (Dytiscidae, Coleoptera), Pericoma larvae (Psychodidae, Diptera), and Hyrgotus adults (Dytiscidae, Coleoptera). Semipalmated sandpipers rely heavily on horseshoe crab eggs during spring migration. Feeding behavior consists of running along the water's edge, pecking and probing in the ground along damp or flooded mud flats. When invertebrates are abundant, semipalmated sandpipers also forage along marsh edges.
Semipalmated sandpipers use both visual and tactile foraging to collect food, depending on the food source. They actively defend feeding territories year-round, though they are much more vigilant while breeding.
Females will also eat small mammal bones as an extra source of calcium during egg laying. ("The Cornell Lab of Ornithology", 2009; Hicklin and Gratto-Trevor, 2010; Shepherd and Boates, 2001; del Hoyo, et al., 1996)
The predominate predators of the semipalmated sandpiper are merlins (Falco columbarius) and other members of the falcon, and accipitor families. Other documented predators include snowy owls and some jaegers. (Lank, et al., 2003; McCurdy, et al., 1999; Safriel, 1975)
Semipalmated sandpipers impact populations of their prey. They also are host to parasites such as parasitic nematodes (Skrjabinoclava morrisoni) which are transmitted through ingesting amphipods Corophium volutator. Eggs and chicks often are eaten by predators such as gulls, jaegers, and foxes. (Safriel, 1975)
Historically semipalmated sandpipers were hunted as game birds, however this is now illegal in the United States under the Migratory Bird Treaty Act of 1918. The mass migration of semipalmated sandpipers and other shorebirds is a major attraction, bringing avid birders to coastal staging areas in spring and fall. (Hicklin and Gratto-Trevor, 2010)
Spring migration of semipalmated sandpipers is critically dependent upon food resource availability on the staging grounds. Delaware Bay, among other east coast locations, is considered an essential stopover for the 3000 to 4000 km journey. Spring migration coincides with the spawning of horseshoe crabs which provides millions of energy-rich eggs to resting semipalmated sandpipers. Unfortunately, the horseshoe crab industry ultimately depends on these eggs as well. Semipalmated sandpipers then compete with the horseshoe crab industry and can impact the economic well-being of the industry. (Berkson and Shuster, Jr., 1999)
Semipalmated Sandpipers are not threatened, however population surveys starting in 1986 have showed a slight decrease in overall population size. The decline is suspected to be a result of human activity. Specific impacts by people include destruction and manipulation of shorelines and wetlands which are habitats for semipalmated sandpipers during both breeding and nonbreeding seasons. Large scale baitworm harvest along coastal areas in known stopping grounds for semipalmated sandpipers has been shown to negatively affect the birds feeding habits due to scarcity of food resources. Poaching of semipalmated sandpipers still occurs on their wintering grounds in South America and is suspected to have a significant effect on populations. Pollution is also suspected to have a negative effect.
Canada and the United States have created detailed conservation plans to protect and enhance staging grounds for migratory shorebirds, including semipalmated sandpipers. ("The Cornell Lab of Ornithology", 2009; Hicklin and Gratto-Trevor, 2010; Peterson, et al., 2009; Shepherd and Boates, 2001; del Hoyo, et al., 1996)
Joseph Landy (author), Florida State University, Emily DuVal (editor), Florida State University, Rachelle Sterling (editor), Special Projects.
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.
living in the southern part of the New World. In other words, Central and South America.
uses sound to communicate
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.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
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.
an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.
parental care is carried out by females
A substance that provides both nutrients and energy to a living thing.
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).
parental care is carried out by males
makes seasonal movements between breeding and wintering grounds
eats mollusks, members of Phylum Mollusca
Having one mate at a time.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
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.
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
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).
Living on the ground.
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
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
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.
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.
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.
A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.
uses sight to communicate
young are relatively well-developed when born
2009. "The Cornell Lab of Ornithology" (On-line).
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Gough, G. 2012. "United States Geological Survey" (On-line). Patuxent Bird Identification InfoCenter. Accessed February 11, 2010 at http://18.104.22.168/id/framlst/i2460id.html.
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Hicklin, P., C. Gratto-Trevor. 2010. "The Birds of North America" (On-line). Semipalmated Sandpiper (Calidris pusilla). Accessed November 16, 2010 at http://bna.birds.cornell.edu/bna/species/006.
Jehl, J. 2006. COLONIALITY, MATE RETENTION, AND NEST-SITE CHARACTERISTICS IN THE SEMIPALMATED SANDPIPER. The Wilson Journal of Ornithology, 18/4: 478–484.
Lank, D., R. Butler, R. Ydenberg, J. Ireland. 2003. Effects of predation danger on migration strategies of sandpipers. OIKOS, 103: 303-319.
McCurdy, D., M. Forbes, J. Boates. 1999. Evidence that the parasitic nematode Skrjabinoclava manipulates host Corophium behavior to increase transmission to the sandpiper, Calidris pusilla.. Behavioral Ecology, 19: 351-357.
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Shepherd, P., J. Boates. 2001. Effects of a Commercial Baitworm Harvest on Semipalmated Sandpipers and Their Prey in the Bay of Fundy Hemispheric Shorebird Reserve. Conservation Biology, 13/2: 347 - 356.
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