The Savannah sparrow (Passerculus sandwichensis ) is a small New World sparrow. It was the only member of the genus Passerculus and is typically the only widely accepted member. Comparison of mtDNA NADH dehydrogenase subunit 2 and 3 sequences indicates that the Ipswich sparrow, formerly usually considered a valid species (as Passerculus princeps ), is a well-marked subspecies of the Savannah sparrow, whereas the southwestern large-billed sparrow should be recognized as a distinct species (Passerculus rostratus ).
The species name sandwichensis is Latin, of place, Sandwich, Unalaska, or Aleutians area, from which came the first subspecies, Aleutian Savannah Sparrow, to be described. The common name honors Savannah, Georgia where Alexander Wilson discovered the species in 1811.
The Savannah sparrow is a small American sparrow. It has a typically sparrow-like dark-streaked brown back, and whitish underparts with brown or blackish breast and flank streaking. It has whitish crown and supercilium stripes, sometimes with some yellow (more often near the beak). The cheeks are brown and the throat white. The flight feathers are blackish-brown with a light brown or white border. The eyes are dark. The feet and legs are horn-colored, as is the lower part of the bill, with the upper part being dark grey.
Savannah sparrows breed in Alaska, Canada, northern, central, and Pacific coastal United States, Mexico, and Guatemala. The Pacific and Mexican breeders are resident, but other populations are migratory, wintering from the southern United States across Central America and the Caribbean to northern South America. These birds inhabit open grasslands, tundra, shrubland, meadows, wetlands, and agricultural fields. They can also be found on beaches, sand dunes, salt marshes, and estuaries.
Savannah sparrows are social birds and typically spend time in pairs or family groups in the breeding season. However, before the winter migration, they assemble in large flocks and become very energetic and noisy. Their flight call is a thin 'seep' and the song is a mixture of 'chirps' and trills. Savannah sparrows are diurnal; they forage by day on the ground or in low bushes. Particularly in winter, they can also be found in grazed low-growth grassland. They feed by walking along the ground and occasionally run or hop to snatch their prey. They will also make short flights to catch insects in mid-air.
Savannah sparrows are herbivores (granivores) and carnivores (insectivores). During winter they mainly eat seeds, but in the breeding season switch their diet to insects and spiders.
In the northern part of their range, Savannah sparrows are polygynous and males mate with more than one female; however, in other areas, these birds are monogamous and form pairs. Males return to the breeding grounds a week before females and establish territories and attract mates. Savannah sparrows usually hide their nests in densely vegetated areas. The nest is an open cup made of grass, lined with finer grass. It is located on the ground or low shrubs. The female lays 2-6 eggs and incubates them about 10 to 13 days. The chicks are born helpless and remain in the nest for 8-11 days. After the young fledge parents continue to feed them until they are 3 weeks old.
Savannah sparrows are widespread and abundant; however, they are susceptible to the loss of their natural habitat, the use of pesticides, and early mowing or haying which disrupts the nests before chicks have fledged.
According to Partners in Flight resource, the total population size of the Savannah sparrow is 170,000,000 breeding individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
