Original description: Emberiza sandwichensis Gmelin 1788
AOU 1 (1886): Sandwich Sparrow, Ammodramus sandwichensis; Savanna Sparrow, Ammodramus sandwichensis savanna; Western Savanna Sparrow, Ammodramus sandwichensis alaudinus; Bryant’s Marsh Sparrow, Ammodramus sandwichensis bryanti
AOU 2 (1895): Sandwich Sparrow, Ammodramus sandwichensis; Savanna Sparrow, Ammodramus sandwichensis savanna; Western Savanna Sparrow, Ammodramus sandwichensis alaudinus; Bryant’s Marsh Sparrow, Ammodramus sandwichensis bryanti
AOU 3 (1910): Aleutian Savannah Sparrow, Passerculus sandwichensis sandwichensis; Savannah Sparrow, Passerculus sandwichensis savanna; Western Savannah Sparrow, Passerculus sandwichensis alaudinus; Bryant’s Sparrow, Passerculus sandwichensis bryanti
AOU 4 (1931): Eastern Savannah Sparrow, Passerculus sandwichensis savanna; Labrador Savannah Sparrow, Passerculus sandwichensis labradorius; Western Savannah Sparrow, Passerculus sandwichensis alaudinus; Aleutian Savannah Sparrow, Passerculus sandwichensis sandwichensis; Nevada Savannah Sparrow, Passerculus sandwichensis nevadensis; Bryant’s Sparrow, Passerculus sandwichensis bryanti
AOU 5 (1957): Savannah Sparrow, Passerculus sandwichensis labradorius, Passerculus sandwichensis savanna, Passerculus sandwichensis oblitus, Passerculus sandwichensis brooksi, Passerculus sandwichensis anthinus, Passerculus sandwichensis sandwichensis, Passerculus sandwichensis nevadensis, Passerculus sandwichensis rufofuscus, Passerculus sandwichensis alaudinus, Passerculus sandwichensis beldingi, Passerculus sandwichensis anulus, Passerculus sandwichensis sanctorum, Passerculus sandwichensis guttatus, Passerculus sandwichensis magdalenae, Passerculus sandwichensis rostratus, Passerculus sandwichensis atratus
AOU 6 (1983): Savannah Sparrow, Passerculus sandwichensis
AOU 7 (1998): Savannah Sparrow, Passerculus sandwichensis
IUCN Conservation Status: Of least concern
Behavior: Usually tame but alert in migration and winter, Savannah Sparrows are considerably shyer on the breeding grounds. In the mid-nineteenth century, Thomas Brewer found them “particularly cautious and mistrustful” in the immediate vicinity of the nest, so elusive that he was unable to collect adult birds from the nest, “and only accomplished [their] identification by means of snares.” Indeed, breeding birds are generally detected only when the male climbs a sturdy grass stalk or perched atop a dried forb to sing; even singing territorial birds are easily flushed back into cover.
Migrants and winter birds are easier to see. Savannah Sparrows appear in almost any open habitat, from farm fields to beaches to suburban lawns, where they feed on the ground in loose, shuffling flocks. When disturbed by a human or other potential predator, they may briefly freeze in place or run a few feet before launching into strong flight. Savannah Sparrows almost always call on flushing, a high, slightly scratchy, and very short tsit, repeated at irregular intervals of a second or more.
The same looseness of association that characterizes feeding flocks on the ground is typical of Savannah Sparrows in flight. Flock members may take off one at a time, and frequently fly in different directions, scattering before alighting. Over longer distances, the flight is flowing and swooping, recalling that of a Horned Lark. Wintering and migrating Savannah Sparrows often land in the open in sparsely leafed trees or bushes or perch on tall grass stems or wires to look back at their pursuer, quite unlike the panicked fluttering and barely controlled landings of such other open-country species as Baird, Grasshopper, and Henslow Sparrows, which immediately seek the shelter of the thickest, darkest clump of grass.
Habitat: Savannah Sparrows nest in areas of denser, taller grass with scattered low shrubs and forbs, including pastureland, marshy grasslands, hay fields, and tundra.
Voice: Males sing perched atop grass stems, bushes, low trees, and fences, or from the ground. There is also an infrequently observed song flight, issued “after force-copulating with neighboring female” or “besting neighboring male in physical territorial dispute.” The precise structure of the territorial song is unique to each individual male, but all can be recognized by the serial combination of high-pitched ticking notes, a broadly modulated, flatulent buzz, and a short, thin concluding trill: tik tik tik brrrzzz bee-eee-eee. At a distance, only the central buzz may be audible; it is “thicker,” lower-pitched, and slower than the more penetrating final trill of a Grasshopper Sparrow.
Even by the standard of grassland passerellids, Savannah Sparrows are persistent singers, heard through the day and occasionally even at night. Such volubility may be connected to the species’ tendency to polygyny. In good habitat, where food is plentiful and the breeding season relatively long, a substantial portion of males may form pair bonds with more than one female and assist in the rearing of more than one brood; when conditions are less favorable, and in northern areas where the breeding season is shorter, monogamy is more likely. Copulation without the accompanying pair bond is also frequent.
Detailed description and measurements drawn from standard reference works
This description is based on the widespread and abundant western subspecies nevadensis; similar birds can occur in nearly all populations. Individual plumage variation produces birds that are darker, paler, browner, grayer, and more sparsely or more densely streaked than other individuals in the same population.
Adult: Tail feathers short and strongly tapered at tips, gray-brown with the outer vanes edged whitish-gray in fresh plumage. Upper tail coverts and rump tan-brown with black shaft streaks taking up approximately one third of the feather’s width. Ground color of the back brown-gray; conspicuous streaking above dark brown to black, the back feathers edged with dull whitish, creating regular pattern of black streaks and parallel “white” tracks down mantle. Primaries plain gray-brown, secondaries brighter, deeper chestnut in most individuals. Tertials black with dull chestnut edges. Greater coverts deep chestnut like secondaries, with large black teardrops and pale buffy edges creating inconspicuous lower wingbar. Median coverts brown at base, with large black teardrops and rounded whitish tips, creating inconspicuous upper wingbar. Nape paler gray brown with very fine blackish streaking. Ground color of underparts white, with buffy tinge to flanks and rarely to breast sides. Fine black-brown streaking on breast, breast sides, flanks, and often upper belly. White throat with or without fine black streaks or spots. Lateral throat stripe blackish, narrow but widening at bottom of throat; often very narrow or nearly absent at top. Wide jaw stripe white, bordered above by fine black whisker. Ear coverts pale brown or gray, with poorly defined rear border. Narrow eye ring, most conspicuous below, broken by thin black eye line, often obscure in front of eye. Long, broad supercilium varying from cream-gray to soft yellow, usually brightest above the lore. Brown-gray crown with finely black-streaked lateral stripes surrounding a narrow white median stripe, often unmarked at front of crown, finely and irregularly streaked at rear of crown. Rather slender bill dull pink, with irregular dark culmen and sometimes tip. Long tarsi and toes fairly bright pink, contrasting with white belly.
Juvenile: Buffier above, with less well-organized streaking. Underparts with more extensive tan-buff tinge, the streaking browner and less regular. Broad creamy-gray supercilium often with more conspicuous black streaks.
Wing chord 65-72 mm (2.6-2.8 inches)
Tail 49-50 mm ( 1.9-2.0 inches)