Smith's Longspur Life History

Habitat

Smith’s Longspurs nest in arctic lowlands where tundra meets forest, in wet meadows of sedges and rushes dotted with stunted trees, especially spruce, birch, willow, and tamarack, as well as bog rosemary, Lapland rhododendron, and bearberry. They also nest in valleys or saddles in more montane areas, up to 5600 feet elevation, where alpine tundra includes scattered shrubs and small trees. In all cases, their preferred breeding habitat is patchy, and so they tend to occur in clusters of breeding groups. During migration, and in winter, Smith’s Longspurs use grasslands, stubble fields, mowed fields at airports, and cattle pastures that are moderately to heavily grazed. They frequent grassy areas around remote lakes, often places where mosses also grow. Among the key grass species for Smith’s Longspur are silver beardgrass, little bluestem, purple three-awn grass, and various species of panic-grasses. Unlike on their nesting grounds, Smith’s Longspurs on the wintering ground tend to avoid grasslands where bushes, shrubs, or trees are present.

Food

Smith’s Longspurs eat seeds and insects. They forage mostly on the ground, much in the manner of a typical sparrow. They seize insects and other arthropods with the bill, sometimes removing the legs and wings before consuming, and they remove the husks of seeds with the bill before swallowing. Unlike many sparrows, they do not forage using their feet to reveal food but do sometimes flip or root through vegetation and debris with the bill when searching for food. On occasion, they glean insects from taller foliage or pursue an insect in flight. Their nesting-season diet is dominated by insects, which they also feed to nestlings, while the nonbreeding season diet contains mostly seeds of grasses and forbs, including timothy grass, poverty dropseed, smooth crabgrass, bristlegrass, clover, ragweed, sedge, and bulrush, as well as crops like wheat and millet. Among their known prey items are adult and larval ants, beetles, butterflies, moths, grasshoppers, dragonflies, midges, caddisflies, craneflies, mosquitoes, spiders, and snails.

Nesting

Nest Placement

The female selects a nest site in tundra, usually near or on a raised hummock; the nest is often set beneath a shrub or tuft of grass and is sunken into the terrain.

Nest Description

The female constructs a cup of grass and sedge stalks and lines it with hair, wool, lichen, ptarmigan feathers, and caribou hair. Nests average about 3.8 inches across and 2.0 inches across, with interior cup 2.2 inches across and 1.5 inches deep.

Nesting Facts

Behavior

Smith’s Longspurs’ have a complex mating system. Males sing primarily to attract females, not to mark a territory. They sometimes sing loudly when another male appears or raise the crown feathers, stand erect, and spread the tail, but it is also common to see 2 males singing in the same shrub. Male home ranges can cover 40 acres and overlap with the home ranges of 2-5 other males, Each male roams widely through this area, singing from rocks and small trees. Instead of guarding a territory, the male attempts to guard a female, and so the male moves around with a female, mating with her and trying to prevent other males from doing the same. However, this male also mates with one or two other females during this period—which provides ample opportunities for other males to move in and mate with the unguarded female as well. Females have smaller home ranges than males (averaging 26 acres), and these ranges overlap with those of 2­–5 other females. Like males, females actively seek opportunities to mate with multiple males. In all, both males and females routinely mate with several different individuals during the course of a single nest attempt—this is known as a "polygynandrous" mating system. Females appear to be the ones to choose their mates in virtually all cases.

Careful research on the breeding ground reveals that Smith’s Longspurs mate more than 350 times per season, with an average of two partners. This results in three out of every four nests containing chicks with different fathers. The females form different strengths of bonds with multiple males. Often, two or three males may bring food to the nestlings at one nest, with the amount of food brought corresponding fairly closely to the number of chicks the father has in the nest.

During migration and on the wintering grounds, Smith’s Longspurs are sociable, traveling and foraging in small flocks. They tend to forage 10 feet or more away from others of their species and do not often flock with other open-country birds such as Horned Larks, although they do sometimes forage with Lapland Longspurs.

Conservation

There is little information on population trends of Smith’s Longspur owing to its remote breeding habitat. Partners in Flight estimates a global breeding population of 75,000 and rates the species a 13 out of 20 on the Continental Concern Score, indicating a species of low conservation concern. Although its breeding habitats remain relatively undisturbed, climate change may alter them as shrubs and trees begin to advance northward and upslope across the tundra. Their wintering habitats are vulnerable to changes in land use.

Credits

Briskie, James V. (2009). Smith's Longspur (Calcarius pictus), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Partners in Flight (2017). Avian Conservation Assessment Database. 2017.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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