Bird of the Month: Savannah Sparrow
By Hugh Jennings
PC: Mick Thompson (Savannah Sparrow)
Scientific Name: Passerculus sandwichensis
Length 5.5 in
Wingspan 6.75 in
AOU Band code SASP
The Savannah Sparrow (SASP) is 5.5" long with a 6.75" wingspan. The genus name Passerculus is from the Latin meaning little sparrow. 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 SASP is highly variable. Most have yellow or whitish lores and eyebrow with a pale crown stripe and a dark whisker stripe. The upper breast and sides are streaked and it sometimes has a dark central spot. It has a short and notched tail. The numerous subspecies (21) vary geographically in size, color, bill size, and extent of streaking.
These sparrows are common in open habitats, marshes, and grasslands. The male sings to defend nesting territory and to attract a mate. The song begins with 2-3 chip notes, followed by two buzzy trills, the second trill lower than the first. One rendition is ti ti ti tseeeeee tisoooo.
Its diet is mostly insects, such as beetles, grasshoppers, caterpillars, flies, spiders, and others. Coastal birds will eat tiny crustaceans and mollusks. They also eat many seeds, mainly from grasses, weeds and some berries. Most foraging is done while walking or running on the ground, but it also forages in shrubs and small trees.
Nest sites are on the ground, usually hidden among grass or weeds and placed under matted dead plants or under overhanging grass, so the nest can only be approached through a tunnel from one side. The nest, built by the female, is an open cup made of grass and lined with finer grass. There are 2-6 eggs, typically 4, with more eggs tending to be laid in the north. The eggs are whitish to pale tan or greenish, with brown markings concentrated at the large end. The female incubates the eggs for 10-13 days. Both parents bring food to the nestlings. The young leave the nest about 8-11 days after hatching. They may have 1 or 2 broods per year.
Migration is mostly early in the spring and late in the fall and may be spread over a considerable period of time. Migration occurs mostly at night.