A long-distance migrant (2), the upland sandpiper leaves its northerly breeding areas around mid-July to late August (3) or early September (2), migrating largely at night to its feeding grounds in South America (3). It arrives in late September to October, and remains there until its departure for North America in mid-February (2). Interestingly, the upland sandpiper spends as little as four months of the year on its breeding grounds (3).
The diet of the upland sandpiper consists mostly of terrestrial insects such as grasshoppers, crickets, weevils and flies, as well as other invertebrates including centipedes, spiders, snails and earthworms (2) (3) (5), and even crayfish (3). This species is also known to feed on seeds and other vegetation (2) (3) (4) (5), but in North America studies have found that 95 to 97 percent of the upland sandpiper’s diet is made up of invertebrates (3). The upland sandpiper forages in fields (4), gleaning low-flying insects and picking them off vegetation as it passes by (3). As it eats crop-damaging insects, the upland sandpiper is often considered to be beneficial to farmers (5). This species has not been observed drinking, and is thought to obtain water from the food it consumes (3).
Adult upland sandpipers, chicks and eggs are all vulnerable to predation by a variety of species, including coyotes (Canis latrans), raccoons (Procyon lotor), mink (Mustela vison), golden eagles (Aquila chrysaetos) and snowy owls (Nyctea scandiaca) (3).
The upland sandpiper is typically a monogamous species (3), and is known to occasionally nest in small, loose colonies (2) (4). This species starts breeding in early to late summer (4), when the male performs courtship displays both in the air and on the ground (3). The upland sandpiper nests in a hollow scrape in the ground, usually in ungrazed upland habitats among dense grass and relatively tall vegetation which provides cover (3) (4) (5). Leaves, grasses and small twigs are used to line the scrape (3) (5).
The female upland sandpiper lays its eggs between May and June (2) (3), and usually only produces one brood per breeding season, only re-nesting if the first clutch gets destroyed or is unsuccessful (3). Each upland sandpiper clutch typically contains about four eggs (2) (3) (4) (5), although larger clutches of up to seven eggs have been recorded (3). The smooth, slightly glossy eggs are variable in colour, ranging from light pinkish-cinnamon to pale olive-buff with even, dark brown spotting, and are relatively large (3). The eggs are incubated for between 21 and 28 days (2) (3) (5), although a period of 23 or 24 days is most common (2) (3). Both sexes are involved in egg incubation (2) (5), although their roles in tending to the chicks once they have hatched are not clear (2), with some reports suggesting that both adult upland sandpipers care for the young until the chicks are able to fly at about 30 to 34 days old (5).
Little information is available on the lifespan of the upland sandpiper, but one ringed bird was known to be 8 years and 11 months old (3).