Spizella pusillafield sparrow

Ge­o­graphic Range

Field spar­rows are found through­out the east­ern United States from just east of the Rocky Moun­tains to the At­lantic Coast and from North Dakota to south­ern Texas in the west and New Hamp­shire to Florida in the east. They are also found in south­ern On­tario and south­ern­most Que­bec. Their breed­ing and win­ter­ing ranges over­lap sub­stan­tially and they are found year-round through­out much of their range ex­cept for the north­ern­most and south­ern­most por­tions. Some pop­u­la­tions are res­i­dent year-round while oth­ers un­der­take short mi­gra­tions. (Carey, et al., 2008)

Habi­tat

Field spar­rows can be com­mon in pre­ferred habi­tat, but are rarely found near human habi­ta­tion, even in ap­pro­pri­ate habi­tat. They are found in open, sa­vanna-like habi­tats, such as suc­ces­sional old fields, for­est edges and open­ings, fencerows and road or rail­way cuts near open fields, and oc­ca­sional or­chards and nurs­eries. They are found only in fields with some trees or shrubs that pro­vide perches. Once suc­ce­sional habi­tats be­come over­grown with trees and shrubs, field spar­rows are no longer found there. (Carey, et al., 2008)

Phys­i­cal De­scrip­tion

Male field spar­rows are slightly larger than fe­males, but both sexes have sim­i­lar plumage. They are red­dish brown on their heads and back with gray, un-streaked bel­lies. They have two white wing bands, a white eye ring, and a rusty brown stripe ex­tend­ing from the eye. Their bill and legs are pink­ish, help­ing to dis­tin­guish them from other spar­rows. They might be con­fused with Worthen's spar­rows (Spizella wortheni) in south­ern New Mex­ico, but they lack the ru­fous stripe from the eye, a dif­fer­ent song, and black legs. (Carey, et al., 2008)

  • Sexual Dimorphism
  • male larger
  • Range mass
    11.4 to 15.7 g
    0.40 to 0.55 oz
  • Range length
    12.5 to 15 cm
    4.92 to 5.91 in

Re­pro­duc­tion

Field spar­rows are monog­a­mous. Males seem to use their sim­ple songs to at­tract a mate, the fre­quency of sim­ple songs de­creases after a pair bond forms. Males ac­com­pany fe­males dur­ing nest build­ing and begin cop­u­la­tory be­hav­ior while the nest is being built. Fe­males seem to find a male mate within a few days of ar­riv­ing in their breed­ing area and re­main with their mate for a breed­ing sea­son. A small num­ber of in­di­vid­u­als mate with each other again in fol­low­ing years. Ex­tra-pair cop­u­la­tions have been ob­served. (Carey, et al., 2008)

Field spar­rows breed from April through Au­gust each year. They lay up to 4 clutches per breed­ing sea­son. Mul­ti­ple nest­ing at­tempts are typ­i­cal be­cause of high rates of nest pre­da­tion and de­ser­tion. Fledg­lings still de­pen­dent on their par­ents have been ob­served as late as Oc­to­ber. Fe­males choose a nest site and con­struct a bowl-like nest of woven grass in veg­e­ta­tion near trees and saplings. Nests early in the sea­son are built on or near the ground, but later in the sea­son, after woody veg­e­ta­tion has leafed out, they may be in the branches of shrubs or small trees. Dur­ing egg lay­ing the par­ents don't seem to pro­tect the nest. If eggs are taken by preda­tors, the par­ents will at­tempt to build a new nest else­where. Fe­males lay from 2 to 5 eggs and begin in­cu­bat­ing just be­fore the last egg is laid. Fe­males may delay in­cu­ba­tion until well after the last egg is laid if the weather is cold and wet. In­cu­ba­tion is gen­er­ally from 11 to 12 days long, but can be from 10 to 17 days. Young fledge 7 to 8 days after hatch­ing, begin to fly at 13 to 14 days after hatch­ing, and be­come in­de­pen­dent within 24 to 36 days after hatch­ing. Young are sex­u­ally ma­ture in the year fol­low­ing their hatch­ing. (Carey, et al., 2008; Na­ture­Serve Ex­plorer, 2008)

  • Breeding interval
    Field sparrows breed in the warm season, attempting several clutches in each breeding season. From 2.9 to 4 clutch attempts per breeding is typical.
  • Breeding season
    Breeding occurs throughout much of the warm season, with eggs laid from April through August.
  • Range eggs per season
    2 to 5
  • Range time to hatching
    10 to 17 days
  • Average time to hatching
    11-12 days
  • Range fledging age
    7 to 8 days
  • Range time to independence
    24 to 36 days
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

Fe­males in­cu­bate eggs and brood hatch­lings, spend­ing about 70% of their time on the nest. Males will oc­ca­sion­ally feed in­cu­bat­ing fe­males. Males and fe­males feed hatch­lings ap­prox­i­mately equally. Young are al­tri­cial at hatch­ing and mostly naked. They de­velop gray downy plumage, their eyes open at 4 days old, and they can stand by about 5 days old. Par­ents con­tinue to feed their young through the hatch­ling phase and into the post-fledg­ing pe­riod; they feed and pro­tect young for 26 to 34 days after hatch­ing, about 17 to 28 days after fledg­ing. Males can take over feed­ing of fledg­lings if the fe­male be­gins to con­struct an­other nest to begin a sub­se­quent brood. (Carey, et al., 2008)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female

Lifes­pan/Longevity

Max­i­mum recorded age in the wild is 8 years 9 months, based on band­ing records. An­nual male sur­vivor­ship is es­ti­mated at 53% and an­nual fe­male sur­vivor­ship at 36%. Win­ter range con­di­tions may re­sult in higher mor­tal­ity. Ap­prox­i­mately 50% of fledg­lings are thought to die be­fore the fall of their hatch year. (Carey, et al., 2008)

  • Average lifespan
    Status: wild
    8.75 years

Be­hav­ior

Field spar­rows are found in ter­ri­to­r­ial, mated pairs dur­ing the breed­ing sea­son and in small flocks dur­ing the win­ter and mi­gra­tion. Breed­ing ter­ri­to­ries are es­tab­lished with song and per­haps some male-male ag­gres­sion, but field spar­rows are gen­er­ally re­ported to be non-ag­gres­sive. They for­age mainly on the ground, hop­ping along to dis­cover seeds, and sleep on perches in woody veg­e­ta­tion. Some pop­u­la­tions un­der­take small mi­gra­tions but other pop­u­la­tions re­main res­i­dent year-round. (Carey, et al., 2008)

Home Range

Breed­ing ter­ri­tory sizes were es­ti­mated at an av­er­age 0.76 ha (range 0.31 to 1.62 ha) in one pop­u­la­tion. (Carey, et al., 2008)

Com­mu­ni­ca­tion and Per­cep­tion

Field spar­rows are rec­og­nized by their dis­tinc­tive, pretty song, con­sist­ing of soft whis­tles that ac­cel­er­ate to­wards a trill. Males use songs to ad­ver­tise ter­ri­to­ries dur­ing the breed­ing sea­son. Young field spar­rows learn songs from their par­ents. Field spar­rows also have a reper­toire of other calls, in­clud­ing a for­ag­ing note ("seep"), courtship calls, trill calls used in ter­ri­to­r­ial de­fense and courtship, cricket calls used by fe­males at the nest, chip calls given in the pres­ence of a threat, and "zeeee" or "eeeee" calls used with threats. (Carey, et al., 2008)

Food Habits

Field spar­rows take seeds, pri­mar­ily grass seeds, through­out the year. Grass seeds make up less than 50% of their diet in the sum­mer, but more than 90% in the win­ter. In the sum­mer, breed­ing sea­son they also take adult and lar­val in­sects and spi­ders. They for­age on the ground, most often near some form of veg­e­ta­tive cover. In the breed­ing sea­son field spar­rows for­age on their own or with a mate, but they form small for­ag­ing flocks in win­ter. They take fallen seeds or land on grass stems and push them to the ground, where they re­move the seeds. They use perches to briefly scan for in­sect prey. (Carey, et al., 2008; Na­ture­Serve Ex­plorer, 2008)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • Plant Foods
  • seeds, grains, and nuts

Pre­da­tion

Ob­served preda­tors of eggs and nestlings in­clude chip­munks (Tamias stria­tus) and many species of snakes (Pan­therophis ob­so­le­tus, Col­u­ber con­stric­tor, Lam­pro­peltis, Thamnophis sir­talis, Lam­pro­peltis cal­li­gaster). The most com­mon preda­tors recorded are black rat snakes (Pan­therophis ob­so­le­tus). Likely preda­tors in­clude red foxes (Vulpes vulpes), grey foxes (Uro­cyon ci­neoar­gen­teus), weasels (Mustela), mink (Neo­vi­son vison), skunks (Mephi­tis mephi­tis), rac­coons (Pro­cyon lotor), and opos­sums (Didel­phis vir­gini­anus). Field spar­rows use a "chip" call to alert oth­ers to a threat. They will use a bro­ken-wing dis­play to dis­tract preda­tors from their nest. (Carey, et al., 2008)

  • Anti-predator Adaptations
  • cryptic

Ecosys­tem Roles

Many kinds of ec­topar­a­sites are found on field spar­rows, in­clud­ing feather mites. They are also in­fected by Plas­mod­ium species. Field spar­rows are im­por­tant preda­tors of grass seeds in their sa­vanna and edge habi­tats. Nests are par­a­sitized by brown-headed cow­birds (Molothrus ater), al­though fre­quency varies re­gion­ally. Most par­a­sitized nests are de­serted by the fe­male. If a field spar­row nest is suc­cess­fully par­a­sitized by brown-headed cow­birds, their over­all nest­ing suc­cess is greatly re­duced and few of the cow­bird nestlings are suc­cess­fully raised. (Carey, et al., 2008)

Com­men­sal/Par­a­sitic Species

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

There are no di­rect pos­i­tive im­pacts of field spar­rows on hu­mans. They are an in­ter­est­ing mem­ber of the na­tive, North Amer­i­can bird fauna and are ap­pre­ci­ated for their song. (Carey, et al., 2008)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no ad­verse ef­fects of field spar­rows on hu­mans.

Con­ser­va­tion Sta­tus

Field spar­rows are sen­si­tive to habi­tat dis­tur­bance and have fairly nar­row habi­tat pref­er­ences. They are not found in areas with human habi­ta­tions, which are ex­pand­ing cur­rently. Avail­able habi­tat may in­crease in areas with re­cent for­est cut­ting, or de­crease in areas with pre­dom­i­nantly suc­ces­sional habi­tats, which be­come in­ap­pro­pri­ate for field spar­rows as they grow. Pop­u­la­tions have ex­pe­ri­enced de­clines across their range, but field spar­rows are wide­spread and fairly com­mon where habi­tat is ap­pro­pri­ate, so they are not con­sid­ered threat­ened cur­rently. How­ever, pop­u­la­tions in Col­orado are con­sid­ered crit­i­cally im­per­iled and pop­u­la­tions in New Hamp­shire, Mass­a­chu­sets, Maine, Que­bec, and the Cana­dian mar­itime provinces are con­sid­ered vul­ner­a­ble. (Carey, et al., 2008; Na­ture­Serve Ex­plorer, 2008)

Con­trib­u­tors

Tanya Dewey (au­thor), An­i­mal Di­ver­sity Web.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

granivore

an animal that mainly eats seeds

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

visual

uses sight to communicate

Ref­er­ences

Carey, M., D. Burhans, D. Nel­son. 2008. Spizella pusilla. Birds of North Amer­ica, 103: 1-20. Ac­cessed March 27, 2009 at http://​bna.​birds.​cornell.​edu/​bna/​species/​103.

Na­ture­Serve Ex­plorer, 2008. "Spizella pusilla" (On-line). Na­ture­Serve Ex­plorer. Ac­cessed March 27, 2009 at http://​www.​natureserve.​org/​explorer/​servlet/​NatureServe?​searchName=Spizella%20pusilla.