Savannah Sparrow

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Savannah Sparrow
Summer bird, Alaska. Probably P. s. anthinus
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Passeriformes Suborder: Passeri Infraorder: Passerida Superfamily: Passeroidea Family: Emberizidae Genus: Passerculus Bonaparte, 1838 Species: P. sandwichensis
Binomial name
Passerculus sandwichensis (Gmelin, 1789)
Subspecies
Some 10-20, see article text

The Savannah Sparrow (Passerculus sandwichensis) is a small American sparrow. It is the only widely accepted member of the genus Passerculus. Recent comparison of mtDNA NADH dehydrogenase subunit 2 and 3 sequences indicates that the Ipswich Sparrow, formerly usually considered a good species (as Passerculus princeps), is a well-marked subspecies of the Savannah Sparrow, whereas the southwestern subspecies should be recognized as distinct species Large-billed Sparrow (Passerculus rostratus).^[1]

It is named after Savannah, Georgia where one of the first specimens of this bird was collected.

This passerine bird breeds in Alaska, Canada, northern, central and Pacific coastal USA, Mexico and Guatemala. The Pacific and Mexican breeders are resident, but other populations are migratory, wintering from the southern United States to northern South America. It is a very rare vagrant to western Europe.

Contents 1 Description 2 Behavior 3 Systematics 3.1 Savannah Sparrows proper 3.2 Ipswich Sparrow 3.3 Large-billed Sparrows 4 Footnotes 5 References 6 External links

[edit] Description

This species has a typically sparrow-like dark-streaked brown back, and whitish underparts with brown or blackish breast and flank streaking. It has a yellowish or whitish crown and eyebrow stripes. The cheeks are brown and the throat white.

The Savannah Sparrow is a very variable species, with numerous subspecies, several of which have been split as separate species at various times. The different forms vary principally in the darkness of the plumage, with Alaskan and interior races the palest, and southwestern coastal forms the darkest; by and large ths agrees with the new species limits. The Savannah Sparrows proper (see below) are very similar and migrant birds can not usually be related to a breeding population with certainty. The resident or partially migratory subspecies are well distinguishable by size and, particularly between groups, coloration. The song is mixture of chirps and trills. The flight call is a thin seep.

[edit] Behavior

These birds forage on the ground or in low bushes. They mainly eat seeds, but insects are also eaten in the breeding season. They form flocks in the winter to migrate.

[edit] Systematics

Seventeen subspecies (including the Large-billed Sparrows) are currently recognized. Four additional subspecies are not generally accepted. The subspecies are usually divided into several groups:

[edit] Savannah Sparrows proper

All are migratory.

• P. s. labradorius, breeds in Newfoundland, Labrador, and N Quebec
• P. s. oblitus, breeds in N Ontario and Manitoba
• P. s. savanna (Eastern Savannah Sparrow), breeds in the NE USA and adjacent Canada (includes P. s. mediogriseus)
• P. s. sandwichensis (Aleutian Savannah Sparrow), breeds on the Aleutian Islands and W Alaskan Peninsula
• P. s. anthinus, breeds in the remainder of Alaska, south and east to central British Columbia and north of the Great Plains to Manitoba
• P. s. brooksi (Dwarf Savannah Sparrow), breeds in southernmost British Columbia to northernmost California
• P. s. alaudinus, breeds in coastal northern and central California
• P. s. nevadensis, breeds in the N Great Plains and the Great Basin
• P. s. brunnescens, breeds from central Mexico south to Guatemala (includes P. s. rufofuscus)

P. s. wetmorei is a doubtful subspecies which may breed in the mountains of Guatemala. It is known from only 5 specimens, collected June 11-17, 1897, in Huehuetenango Department.^{[citation needed]}

[edit] Ipswich Sparrow

Formerly considered a distinct species^[1], some post-breeding dispersal.

• P. s. princeps, breeds almost exclusively on Sable Island

The Ipswich Sparrow is somewhat larger and paler in colour than other eastern Savannah Sparrows. The breast streaks are narrower and pale brown. Some birds overwinter on the island; others migrate south along the Atlantic coast, usually departing later and returning sooner than mainland birds. Some birds interbreed with P. s. savanna in Nova Scotia. These birds frequently raise three broods in a year. This bird was first observed in winter on the dunes near the town of Ipswich, Massachusetts.

[edit] Large-billed Sparrows

The Large-billed Sparrows proper are 2-3 dark, large and strong-billed subspecies:

• Passerculus rostratus rostratus (or P. s. rostratus), which breed on the Gulf Coast of NE Baja California and NW Sonora (some post-breeding dispersal).
• P. r. atratus (or P. s. atratus), resident on the coast of central Sonora to central Sinaloa (resident)

The Belding's (Savannah/Large-billed) Sparrows are all-year residents of salt marshes of the Californian Pacific coast. They are dark, rufous, and have rather long but not very hefty bills.

• P. r. beldingi (or P. s. beldingi), resident on the Pacific Coast from Morro Bay, California, to El Rosario, Baja California (includes P. r./s. bryanti)
• P. r. anulus (or P. s. anulus), resident around Sebastián Vizcaíno Bay, Baja California
• P. r. guttatus (or P. s. guttatus), resident around San Ignacio Lagoon
• P. r. magdalenae (or P. s. magdalenae), resident around Magdalena Bay

The San Benito (Savannah/Large-billed) Sparrow is a resident bird of the Islas San Benito off Baja California; a stray bird was observed on Cedros Island on April 21, 1906^[2]

• P. r. sanctorum (or P. s. sanctorum)

This is a large-bodied and large-billed subspecies, similar to rostratus. They utilize different habitat and their breeding season does not seem to coincide with that of Belding's Sparrows^[3]. However, their bill size is due to convergent evolution and their habitat choice simply to the lack of alternatives on their barren island home; altogether, it appears to be a fairly recent offshoot from the Belding's Sparrows group. It appears as distinct evolutionarily from these as does the Ipswich Sparrow from the Savannah Sparrow proper group, only that there seems to have been more gene flow and/or a larger founder population in the case of the latter.^[1]

[edit] Footnotes

1. ^ ^{a b c} Zink et al. (2005)
2. ^ Thayer & Bangs (1907)
3. ^ For late April 1906, Thayer & Bangs (1907) report nestlings, young birds molting into adult plumage, but no eggs anymore. Rising in Zink et al. (2005) found no breeding activity in late April 1999. Consequently, breeding seems to take place in the winter months, with the last young fledging in April/May.

[edit] References

• BirdLife International (2004). Passerculus sandwichensis. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006. Database entry includes justification for why this species is of least concern
• Byers, Clive; Olsson, Urban & Curson, Jon (1995): Sparrows and Buntings: A Guide to the Sparrows and Buntings of North America and the World. Houghton Mifflin, Boston. ISBN 0-395-73873-3
• Thayer, John E. & Bangs, Outram (1907): Birds Collected by W. W. Brown, Jr., on Cerros [sic], San Benito and Natividad Islands in the Spring of 1906, with Notes on the Biota of the Islands. Condor 9(3): 77-81. doi:10.2307/1361136 PDF fulltext
• Zink, Robert M.; Rising, James D.; Mockford, Steve; Horn, Andrew G.; Wright, Jonathan M.; Leonard, Marty & Westberg, M.C. (2005): Mitochondrial DNA variation, species limits, and rapid evolution of plumage coloration and size in the Savannah Sparrow. Condor 107(1): 21–28. doi:10.1650/7550 (HTML abstract)

[edit] External links

• Species at risk - Ipswich Sparrow
• Savannah Sparrow Species Account - Cornell Lab of Ornithology
• Savannah Sparrow Information and Photos - South Dakota Birds and Birding
• Savannah Sparrow Passerculus sandwichensis - USGS Patuxent Bird Identification InfoCenter