Savannah sparrow

The Savannah sparrow (Passerculus sandwichensis) is a small New World sparrow that is the only member of the genus Passerculus. It is a widespread and abundant species that occupies open grassland habitats in North America.

Over most of its range it is migratory, breeding in Canada and the northern United States while wintering in Mexico and the southern United States. It is sexually monomorphic species that is quite variable in appearance. Around 17 subspecies are currently recognised. These are divided into several groups, some of which have sometimes been considered as separate species.

The species name sandwichensis is Latin from Sandwich Sound (now Prince William Sound) in southern Alaska from where the first specimen was collected. The common name refers to Savannah, Georgia, where Alexander Wilson observed the species in 1811.

Taxonomy
The Savannah sparrow was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the buntings in the genus Emberiza and coined the binomial name Emberiza sandwichensis. Gmelin based his text on the Sandwich bunting that had been described by John Latham in 1783 and the "Unalasha bunting" that had been described by Thomas Pennant in 1785. Latham and Pennant had access to a specimen owned by the naturalist Joseph Banks that had been collected in May 1778 from Sandwich Sound (now Prince William Sound) in southern Alaska during James Cook's third voyage to the Pacific Ocean. The specimen has not survived, but a coloured drawing of the bird made during the voyage by the artist and naturalist William Ellis is now held by the Natural History Museum in London.

The Savannah sparrow is now the only species placed in the genus Passerculus that was introduced in 1838 by the French naturalist Charles Bonaparte. The English name "Savannah sparrow" was introduced in 1811 by the Scottish-American ornithologist Alexander Wilson in the third volume of his American Ornithology; or, the Natural History of the Birds of the United States. Wilson had first seen the species on the coast near Savannah, Georgia.

A 2005 study that compared mitochondrial DNA sequence found that the Ipswich sparrow, formerly usually considered a valid species (as Passerculus princeps), was a well-marked subspecies, whereas the southwestern large-billed sparrow was more distinct (Passerculus rostratus).

Seventeen subspecies (including the large-billed sparrows) are currently recognized, though many are only described from wintering birds and much of the variation seems to be clinal. Four additional subspecies are no longer generally accepted. The complex is usually divided into several groups:

Savannah sparrows proper
All are migratory; wintering ranges overlap widely.
 * P. s. labradorius Howe, 1901 – breeds in Newfoundland, Labrador, and N Quebec. Includes P. s. oblitus.
 * P. s. savanna (Wilson, A, 1811) – (eastern Savannah sparrow), breeds in the northeast US and adjacent Canada (includes P. s. mediogriseus)
 * P. s. sandwichensis (Gmelin, JF, 1789) – (Aleutian Savannah sparrow), breeds on the Aleutian Islands and west Alaskan Peninsula
 * P. s. anthinus Bonaparte, 1853 – breeds in the remainder of Alaska, south and east to central British Columbia and north of the Great Plains to Manitoba. Includes P. s. crassus.
 * P. s. brooksi Bishop, 1915 – (dwarf Savannah sparrow), breeds in southernmost British Columbia to northernmost California
 * P. s. alaudinus Bonaparte, 1853 – breeds in coastal northern and central California
 * P. s. nevadensis Grinnell, 1910 – breeds in the northern Great Plains and the Great Basin
 * P. s. brunnescens (Butler, AW, 1888) – breeds from central Mexico south to Guatemala (includes P. s. rufofuscus)
 * P. s. wetmorei Van Rossem, 1938 – a doubtful subspecies that may breed in the mountains of Guatemala. It is known from only five specimens, collected June 11–17, 1897, in Huehuetenango Department.

Ipswich sparrow
Some post-breeding dispersal. Formerly considered as a distinct species.
 * P. s. princeps Maynard, 1872 – breeds almost exclusively on Sable Island which lies southeast of Nova Scotia in the North Atlantic Ocean.
 * The Ipswich sparrow is somewhat larger and paler in color 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.



Large-billed sparrows
The large-billed sparrows proper is sometimes treated as a separate species. There are two dark, large and strong-billed subspecies:
 * P. s. rostratus (Cassin, 1852) – breeds on the Gulf Coast of northeast Baja California and northwest Sonora (some post-breeding dispersal).
 * P. s. atratus Van Rossem, 1930 – resident on the coast of central Sonora to central Sinaloa (resident)

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. This group has been considered as a separate species.
 * P. s. beldingi Ridgway, 1885 – resident on the Pacific coast from Morro Bay, California, to El Rosario, Baja California (includes P. r./s. bryanti)
 * P. s. anulus Huey, 1930 – resident around Sebastián Vizcaíno Bay, Baja California
 * P. s. guttatus Lawrence, 1867 – resident around San Ignacio Lagoon
 * P. s. magdalenae Van Rossem, 1947 – resident around Magdalena Bay

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. It has been considered as a separate species.
 * P. s. sanctorum Coues, 1884
 * 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. 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.

Description
The Savannah sparrow 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 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.

It 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. The variation generally follows Gloger's rule, with Alaskan and interior races the palest, and southwestern coastal forms the darkest. There are some exceptions, though, most conspicuously in some island populations that presumably were strongly affected by founder effects. The general pattern of variation has a fairly clear divide, southwest of which the birds become notably darker; this agrees quite well with the limit between P. sandwichensis and P. (s.) rostratus. Savannah sparrows show some variation in size across subspecies. The total length can range from 11 to 17 cm, wingspan ranges from 18 to 25 cm and body mass from 15 to 29 g. In the nominate subspecies, the body weight averages 20.1 g.

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.

Distribution and habitat
This passerine bird breeds 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. It is a very rare vagrant to western Europe.

Behavior
These birds forage on the ground or in low bushes; particularly in winter they are also found in grazed low-growth grassland. They mainly eat seeds, but also eat insects in the breeding season. They are typically encountered as pairs or family groups in the breeding season, and assemble in flocks for the winter migration. The flight call is a thin seep. Sensu lato, the Savannah sparrow is considered a threatened species by the IUCN. The song is mixture of chirps and trills.

Book

 * Rising JD. (1980). Inter Populational Size Variation in Savanna Sparrows Passerculus-Sandwichensis. THE UNIVERSITY OF BRITISH COLUMBIA. SECOND INTERNATIONAL CONGRESS OF SYSTEMATIC AND EVOLUTIONARY BIOLOGY, VANCOUVER, B.C., CANADA, JULY 17–24, 1980. I+441P. UNIVERSITY OF BRITISH COLUMBIA: VANCOUVER, B.C., CANADA. PAPER. 1980. P429.
 * Wheelwright, N. T. and J. D. Rising. 1993. Savannah Sparrow (Passerculus sandwichensis). In The Birds of North America, No. 45 (A. Poole and F. Gill, Eds.). Philadelphia: The Academy of Natural Sciences; Washington, D.C.: The American Ornithologists’ Union.

Thesis

 * Bingman VP. Ph.D. (1981). ONTOGENY OF A MULTIPLE STIMULUS ORIENTATION SYSTEM IN THE SAVANNAH SPARROW (PASSERCULUS SANDWICHENSIS). State University of New York at Albany, United States, New York.
 * Bradley RA. M.A. (1974). GEOGRAPHIC VARIATION IN THE SONG OF BELDING'S SAVANNAH SPARROW (PASSERCULUS SANDWICHENSIS BELDINGI). California State University, Long Beach, United States, California.
 * Chew GL. M.A. (1979). Species, geographic and individual trends of variation in the song of the Savannah sparrow, Passerculus sandwichensis. Dalhousie University (Canada), Canada.
 * Dixon CL. Ph.D. (1972). A POPULATION STUDY OF SAVANNAH SPARROWS ON KENT ISLAND IN THE BAY OF FUNDY. University of Michigan, United States, Michigan.
 * Freeman-Gallant CR. Ph.D. (1997). Ecology and evolution of male parental care in Savannah Sparrows. Cornell University, United States, New York.
 * LaPointe G. M.Sc. (1983). Bilan spatio-temporel de l'activite du pinson des pres (Passerculus sandwichensis) pendant le cycle reproducteur. Universite Laval (Canada), Canada.
 * Pitocchelli J. M.Sc. (1981). Song dialects, and vocal development of Savannah Sparrows (Passerculus sandwichensis labradorius, Howe) breeding in Newfoundland and the St. Pierre et Miquelon Islands. Memorial University of Newfoundland (Canada), Canada.
 * Reid ML. M.Sc. (1986). SINGING VIGOUR AND MATE CHOICE IN IPSWICH SPARROWS (PASSERCULUS SANDWICHENSIS PRINCEPS). Carleton University (Canada), Canada.
 * Rogers CM. M.S. (1982). THE EFFECT OF AGGRESSION ON BREEDING TERRITORY SIZE IN THE SAVANNAH SPARROW PASSERCULUS SANDWICHENSIS. Michigan State University, United States, Michigan.
 * Rogers EI. Ph.D. (1990). The influence of habitat quality and gender on the variable mating system of a territorial passerine, the savannah sparrow. Michigan State University, United States, Michigan.
 * Sung H-C. Ph.D. (2005). Song variation and male reproductive success in the Savannah sparrow songs, Passerculus sandwichensis. The University of Western Ontario (Canada), Canada.
 * Temple M. M.Sc. (2001). Microsatellite analysis of extra-pair fertilizations in the Ipswich sparrow (Passerculus sandwichensis princeps). Dalhousie University (Canada), Canada.
 * Wagner SJ. Ph.D. (2004). Variation in levels of monoamines and their metabolites in the brains of Savannah sparrows (Passerculus sandwichensis). Clemson University, United States, South Carolina.
 * Weatherhead PJ. Ph.D. (1978). THE ECOLOGY AND BEHAVIOR OF REPRODUCTION IN A TUNDRA POPULATION OF SAVANNAH SPARROWS. Queen's University at Kingston (Canada), Canada.
 * Weatherhead PJ. Ph.D. (1978). The ecology and behavior of reproduction in a tundra population of Savannah sparrows. Queen's University at Kingston (Canada), Canada.

Articles

 * Able KP & Able MA. (1990). Ontogeny of Migratory Orientation in the Savannah Sparrow Passerculus-Sandwichensis Calibration of the Magnetic Compass. Animal Behaviour. vol 39, no 5. p. 905-913.
 * Able KP & Able MA. (1990). Ontogeny of Migratory Orientation in the Savannah Sparrow Passerculus-Sandwichensis Mechanism at Sunset. Animal Behaviour. vol 39, no 6. p. 1189-1198.
 * Able KP & Able MA. (1993). Magnetic orientation in the Savannah sparrow. Ethology. vol 93, no 4. p. 337-343.
 * Able KP & Able MA. (1996). The flexible migratory orientation system of the Savannah sparrow (Passerculus sandwichensis). Journal of Experimental Biology. vol 199, no 1. p. 3-8.
 * Alsop FJ III. (1977). Savannah Sparrow Passerculus-Sandwichensis Extends Its Breeding Range into Upper Eastern Tennessee. American Birds. vol 31, no 6. p. 1101-1102.
 * Baptista LF. (1984). El-Nino and a Brumal Breeding Record of an Insular Savannah Sparrow Passerculus-Sandwichensis-Sanctorum. Wilson Bulletin. vol 96, no 2. p. 302-303.
 * Bedard J & Lapointe G. (1984). Banding Returns Arrival Times and Site Fidelity in the Savannah Sparrow Passerculus-Sandwichensis. Wilson Bulletin. vol 96, no 2. p. 196-205.
 * Bedard J & Lapointe G. (1984). The Savannah Sparrow Passerculus-Sandwichensis Territorial System Can Habitat Features Be Related to Breeding Success. Canadian Journal of Zoology. vol 62, no 9. p. 1819-1828.
 * Bedard J & Lapointe G. (1985). Influence of Parental Age and Season on Savannah Sparrow Passerculus-Sandwichensis Reproductive Success. Condor. vol 87, no 1. p. 106-110.
 * Bedard J & McNeil JN. (1979). Protocalliphora-Hirudo New-Record Diptera Calliphoridae Infesting Savannah Sparrow Passerculus-Sandwichensis Aves Fringillidae in Eastern Quebec Canada. Canadian Entomologist. vol 111, no 1. p. 111-112.
 * Bedard J & Meunier M. (1983). Parental Care in the Savannah Sparrow Passerculus-Sandwichensis. Canadian Journal of Zoology. vol 61, no 12. p. 2836-2843.
 * Bingman VP. (1983). Importance of Earth Magnetism for the Sunset Orientation of Migratory Naive Savannah Sparrows Passerculus-Sandwichensis. Monitore Zoologico Italiano. vol 17, no 4. p. 395-400.
 * Bingman VP. (1983). Magnetic Field Orientation of Migratory Savannah Sparrows Passerculus-Sandwichensis-Savannah with Different 1st Summer Experience. Behaviour. vol 87, no 1-2. p. 43-53.
 * Bradley RA. (1977). Geographic Variation in the Song of Beldings Savannah Sparrow Passerculus-Sandwichensis-Beldingi. Bulletin of the Florida State Museum Biological Sciences. vol 22, no 2. p. 57-100.
 * Bradley RA. (1994). Cultural change and geographic variation in the songs of the Belding's Savannah sparrow (Passerculus sandwichensis beldingi). Bulletin Southern California Academy of Sciences. vol 93, no 3. p. 91-109.
 * Brower AE. (1973). An Aberrantly Colored Savannah Sparrow from Maine. Auk. vol 90, no 1. p. 206-207.
 * Broyd SJ. (1985). SAVANNAH SPARROW – NEW TO THE WESTERN PALEARCTIC. British Birds. vol 78, no 12. p. 647-656.
 * Burnell K. (1998). Cultural variation in savannah sparrow, Passerculus sandwichensis, songs: an analysis using the meme concept. Animal Behaviour. vol 56, p. 995-1003.
 * Chew L. (1981). GEOGRAPHIC AND INDIVIDUAL VARIATION IN THE MORPHOLOGY AND SEQUENTIAL ORGANIZATION OF THE SONG OF THE SAVANNAH SPARROW (PASSERCULUS-SANDWICHENSIS). Canadian Journal of Zoology-Revue Canadienne De Zoologie. vol 59, no 4. p. 702-713.
 * Chew L. (1983). FINITE STATE GRAMMARS FOR DIALECTS OF THE ADVERTISING SONG OF THE SAVANNAH SPARROW (PASSERCULUS-SANDWICHENSIS). Behavioural Processes. vol 8, no 1. p. 91-96.
 * Cooper BA & Murphy EC. (1985). Savannah Sparrow Passerculus-Sandwichensis Sings a White-Crowned Sparrow Zonotrichia-Leucophrys Song. Animal Behaviour. vol 33, no 1. p. 330-331.
 * Cooper BA & Murphy EC. (1985). SAVANNAH SPARROW SINGS A WHITE-CROWNED SPARROW SONG. Animal Behaviour. vol 33, no FEB. p. 330-331.
 * Davis SD, Williams JB, Adams WJ & Brown SL. (1984). The Effect of Egg Temperature on Attentiveness in the Beldings Savannah Sparrow Passerculus-Sandwichensis-Beldingi. Auk. vol 101, no 3. p. 556-566.
 * Dixon CL. (1978). Breeding Biology of the Savannah Sparrow on Kent Island. Auk. vol 95, no 2. p. 235-246.
 * Ellis PM & Riddiford NJ. (1992). Savannah sparrow in Shetland: Second record for the western Palearctic. British Birds. vol 85, no 10. p. 561-564.
 * Freeman-Gallant CR. (1996). Microgeographic patterns of genetic and morphological variation in Savannah sparrows (Passerculus sandwichensis). Evolution. vol 50, no 4. p. 1631-1637.
 * Freeman-Gallant CR. (1997). Extra-pair paternity in monogamous and polygynous Savannah sparrows, Passerculus sandwichensis. Animal Behaviour. vol 53, no 2. p. 397-404.
 * Freeman-Gallant CR, O'Connor KD & Breuer ME. (2001). Sexual selection and the geography of Plasmodium infection in Savannah sparrows (Passerculus sandwichensis). Oecologia. vol 127, no 4. p. 517-521.
 * Freeman-Gallant CR, Wheelwright NT, Meiklejohn KE & Sollecito SV. (2006). Genetic similarity, extrapair paternity, and offspring quality in Savannah sparrows (Passerculus sandwichensis). Behavioral Ecology. vol 17, no 6. p. 952-958.
 * Freeman-Gallant CR, Wheelwright NT, Meiklejohn KE, States SL & Sollecito SV. (2005). Little effect of extrapair paternity on the opportunity for sexual selection in savannah sparrows (Passerculus sandwichensis). Evolution. vol 59, no 2. p. 422-430.
 * Gobeil RE. (1968). The Double Scratch in the Genus Passerculus Behavior Passerculus-Sandwichensis. Wilson Bulletin. vol 80, no 3. p. 334-335.
 * Goldstein DL, Williams JB & Braun EJ. (1990). OSMOREGULATION IN THE FIELD BY SALT-MARSH SAVANNAH SPARROWS PASSERCULUS-SANDWICHENSIS-BELDINGI. Physiological Zoology. vol 63, no 4. p. 669-682.
 * Gustafson DK. (1971). Savannah Sparrow Wintering in Waukesha. Passenger Pigeon. vol 33, no 4.
 * Johnson OW & Ohmart RD. (1973). Some Features of Water Economy and Kidney Micro Structure in the Large-Billed Savanna Sparrow Passerculus-Sandwichensis-Rostratus. Physiological Zoology. vol 46, no 4. p. 276-284.
 * Jones AL, Shriver WG, Bulgin NL, Lockwood R & Vickery PD. (2003). A probable grasshopper X savannah sparrow hybrid singing a song sparrow song. Wilson Bulletin. vol 115, no 3. p. 231-236.
 * Jorgensen PD & Ferguson HL. (1982). Clapper Rail Rallus-Longirostris-Levipes Preys on Savannah Sparrow Passerculus-Sandwichensis-Beldingi. Wilson Bulletin. vol 94, no 2.
 * La Pointe G & Bedard J. (1984). Seasonal and Individual Variability of Behavior Rates in Male Savannah Sparrows Passerculus-Sandwichensis. Biology of Behaviour. vol 9, no 4. p. 343-356.
 * Lapointe G & Bedard J. (1986). Savannah Sparrow Passerculus-Sandwichensis Reproductive Success. Canadian Field Naturalist. vol 100, no 2. p. 264-267.
 * Liu L, Brookey J, Dimse S, Williams JB & Tallman G. (1981). Genetic Variation in Serum Enzymes of Beldings Savannah Sparrows Passerculus-Sandwichensis-Beldingi. Journal of Heredity. vol 72, no 6. p. 438-440.
 * McLaren IA. (1968). Censuses of the Ipswich Sparrow on Sable Island Nova-Scotia Canada Passerculus-Princeps Passerculus-Sandwichensis. Canadian Field Naturalist. vol 82, no 2. p. 148-150.
 * Meunier M & Bedard J. (1984). Nestling Foods of the Savannah Sparrow Passerculus-Sandwichensis. Canadian Journal of Zoology. vol 62, no 1. p. 23-27.
 * Moore FR. (1980). SOLAR CUES IN THE MIGRATORY ORIENTATION OF THE SAVANNAH SPARROW, PASSERCULUS-SANDWICHENSIS. Animal Behaviour. vol 28, no AUG. p. 684-704.
 * Moore FR. (1982). REVERSE TURNING AND ANGLE COMPENSATION IN A MIGRATORY PASSERINE, PASSERCULUS-SANDWICHENSIS. Behavioural Processes. vol 7, no 3. p. 259-266.
 * Moore FR. (1984). AGE-DEPENDENT VARIABILITY IN THE MIGRATORY ORIENTATION OF THE SAVANNAH SPARROW (PASSERCULUS-SANDWICHENSIS). Auk. vol 101, no 4. p. 875-880.
 * Moore FR. (1985). INDIVIDUAL VARIABILITY IN THE MIGRATORY ORIENTATION OF THE SAVANNAH SPARROW, PASSERCULUS-SANDWICHENSIS. Zeitschrift für Tierpsychologie. vol 67, no 1-4. p. 144-153.
 * Moore FR. (1985). INTEGRATION OF ENVIRONMENTAL STIMULI IN THE MIGRATORY ORIENTATION OF THE SAVANNAH SPARROW (PASSERCULUS-SANDWICHENSIS). Animal Behaviour. vol 33, no MAY. p. 657-663.
 * Moore FR. (1987). MOONLIGHT AND THE MIGRATORY ORIENTATION OF SAVANNAH SPARROWS (PASSERCULUS-SANDWICHENSIS). Ethology. vol 75, no 2. p. 155-162.
 * Muheim R & Akesson S. (2002). Clock-shift experiments with Savannah sparrows, Passerculus sandwichensis, at high northern latitudes. Behavioral Ecology and Sociobiology. vol 51, no 4. p. 394-401.
 * Nagata H & Ishimoto A. (2000). First detailed description of captured Savannah Sparrow Passerculus sandwichensis in Ibaraki Prefecture. Japanese Journal of Ornithology. vol 49, no 1. p. 55-58.
 * Nero RW. (1996). A one-winged Savannah sparrow. Blue Jay. vol 54, no 3.
 * Ouellet H. (1991). SAVANNAH SPARROW ATTENDS NEST OF LAPLAND LONGSPUR. Bird Behaviour. vol 9, no 1-2. p. 30-33.
 * Radvanyi A, Kroeger P, Busby DG & Shaw GG. (1986). Responses of Quail Coturnix-Coturnix Pheasants Phasianus-Colchicus and Sparrows Passerculus-Sandwichensis to One Oral Dose of Dimethoate and to Consumption of Dimethoate Treated Bran Baits. Bulletin of Environmental Contamination & Toxicology. vol 36, no 4. p. 616-621.
 * Rising JD. (1979). SEXUAL DIMORPHISM OF SAVANNAH SPARROWS (PASSERCULUS-SANDWICHENSIS). American Zoologist. vol 19, no 3. p. 963-963.
 * Rising JD. (1987). Geographic Variation in Testis Size in Savannah Sparrows Passerculus-Sandwichensis. Wilson Bulletin. vol 99, no 1. p. 63-72.
 * Rising JD. (1987). Geographic Variation of Sexual Dimorphism in Size of Savannah Sparrows Passerculus-Sandwichensis a Test of Hypotheses. Evolution. vol 41, no 3. p. 514-524.
 * Rising JD. (1988). Geographic Variation in Sex Ratios and Body Size Wintering Flocks of Savannah Sparrows Passerculus-Sandwichensis. Wilson Bulletin. vol 100, no 2. p. 183-203.
 * Rising JD. (1989). SEXUAL DIMORPHISM IN PASSERCULUS-SANDWICHENSIS AS IT IS. Evolution. vol 43, no 5. p. 1121-1123.
 * Rising JD. (2001). Geographic variation in size and shape of Savannah Sparrows (Passerculus sandwichensis). Studies in Avian Biology. vol 23, p. 1-65.
 * Rogers CM. (1985). Growth Rate and Determinants of Fledgling Weight in Michigan-Breeding Savannah Sparrows Passerculus-Sandwichensis. Condor. vol 87, no 2. p. 302-303.
 * Ross HA. (1980). Growth of Nestling Ipswich Sparrows Passerculus-Sandwichensis in Relation to Season Habitat Brood Size and Parental Age. Auk. vol 97, no 4. p. 721-732.
 * Ross HA. (1980). THE REPRODUCTIVE RATES OF YEARLING AND OLDER IPSWICH SPARROWS, PASSERCULUS-SANDWICHENSIS-PRINCEPS. Canadian Journal of Zoology-Revue Canadienne De Zoologie. vol 58, no 9. p. 1557-1563.
 * Ross HA & McLaren IA. (1981). Lack of Differential Survival among Young Ipswich Sparrows Passerculus-Sandwichensis-Princeps. Auk. vol 98, no 3. p. 495-502.
 * Sung H-C & Handford P. (2006). Songs of the Savannah Sparrow: structure and geographic variation. Canadian Journal of Zoology. vol 84, no 11. p. 1637-1646.
 * Threilfall W & Cannings RJ. (1979). Growth of Nestling Savannah Sparrows Passerculus-Sandwichensis. Bird Banding. vol 50, no 2. p. 164-166.
 * Weatherhead PJ. (1980). SEXUAL DIMORPHISM IN 2 SAVANNAH SPARROW POPULATIONS. Canadian Journal of Zoology-Revue Canadienne De Zoologie. vol 58, no 3. p. 412-415.
 * Weatherhead PJ & Robertson RJ. (1978). INTRASPECIFIC NEST PARASITISM IN THE SAVANNAH SPARROW. Auk. vol 95, no 4. p. 744-745.
 * Weatherhead PJ & Robertson RJ. (1980). ALTRUISM IN THE SAVANNAH SPARROW. Behavioral Ecology and Sociobiology. vol 6, no 3. p. 185-186.
 * Weatherhead PJ & Robertson RJ. (1980). Sexual Recognition and Anti Cuckoldry Behavior in Savannah Sparrows Passerculus-Sandwichensis. Canadian Journal of Zoology. vol 58, no 6. p. 991-996.
 * Welsh DA. (1975). SAVANNAH SPARROW BREEDING AND TERRITORIALITY ON A NOVA-SCOTIA DUNE BEACH. Auk. vol 92, no 2. p. 235-251.
 * Wheelwright NT & Beagley JC. (2005). Proficient incubation by inexperienced Savannah Sparrows Passerculus sandwichensis. Ibis. vol 147, no 1. p. 67-76.
 * Wheelwright NT & Mauck RA. (1998). Philopatry, natal dispersal, and inbreeding avoidance in an island population of Savannah Sparrow. Ecology. vol 79, no 3. p. 755-767.
 * Wheelwright NT & Seabury RE. (2003). Fifty : fifty offspring sex ratios in Savannah Sparrows (Passerculus sandwichensis). Auk. vol 120, no 1. p. 171-179.
 * Wiens JA. (1971). Egg Dumping by the Grasshopper Sparrow in a Savannah Sparrow Nest. Auk. vol 88, no 1. p. 185-186.
 * Williams JB & Hansell H. (1981). Bio Energetics of Captive Beldings Savannah Sparrows Passerculus-Sandwichensis-Beldingi. Comparative Biochemistry & Physiology A. vol 69, no 4. p. 783-788.
 * Williams JB & Nagy KA. (1984). Daily Energy Expenditure of Savannah Sparrows Passerculus-Sandwichensis Comparison of Time Energy Budget and Doubly Labeled Water Estimates. Auk. vol 101, no 2. p. 221-229.
 * Williams JB & Nagy KA. (1984). Validation of the Doubly Labeled Water Technique for Measuring Energy Metabolism in Savannah Sparrows Passerculus-Sandwichensis. Physiological Zoology. vol 57, no 3. p. 325-328.
 * Williams JB & Nagy KA. (1985). Daily Energy Expenditure by Female Savannah Sparrows Passerculus-Sandwichensis Feeding Nestlings. Auk. vol 102, no 1. p. 187-190.
 * Williams JB & Nagy KA. (1985). Water Flux and Energetics of Nestling Savannah Sparrows Passerculus-Sandwichensis in the Field. Physiological Zoology. vol 58, no 5. p. 515-525.
 * Williams JB & Prints A. (1986). Energetics of Growth in Nestling Savannah Sparrows Passerculus-Sandwichensis a Comparison of Doubly Labeled Water and Laboratory Estimates. Condor. vol 88, no 1. p. 74-83.
 * Zink RM, Dittmann DL, Cardiff SW & Rising JP. (1991). Mitochondrial DNA Variation and the Taxonomic Status of the Large-Billed Savannah Sparrow. Condor. vol 93, no 4. p. 1016-1019.

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