Because their nests are placed on the ground, fox sparrows face predation by hawks (family Accipitridae), mammalian carnivores (order Carnivora), and possibly snakes (suborder Serpentes). In order to protect their young when there is a predator, adults give a broken wing display. During the display the adult limps around with one wing up, acting as if it was broken, and calls sharply. Once the predator is distracted, the adult flies back to the nest and young.
Known Predators:
Fox sparrows are also referred to as ferruginous finches, foxy finches, fox-colored sparrows, and fox tails. They get their common name from the red or rusty color of their feathers.
Fox sparrows have a voice that is thought to be one of the finest among sparrows. The song is generally presented while the sparrow sits on the top of a bush or on a low branch in a tree. The male usually sings in a concealed area in the territory around its nest. Fox sparrows sing very often during breeding season, but keep themselves hidden at the same time. A distinctive song is one that is used when the bird is alarmed. It is commonly heard when fox sparrows are in some way disturbed near their nest. Singing is occasional, but not common, in the winter.
Communication Channels: acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Fox sparrows are protected under the US Migratory Bird Treaty Act. They are particularly vulnerable to habitat destruction as a result of logging operations.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse affects of Paserella iliaca on humans.
While fox sparrows do not play a large economically important role, they are important in the bird watching community.
Positive Impacts: ecotourism
Fox sparrows act as predators of insects, spiders, millipedes and small snails and are important prey for their predators. It is also interesting to note that fox sparrows are occasionally parasitized by brown-headed cowbirds (Molothrus ater).
Fox sparrows are omnivorous. They forage on the ground by double scratching and quickly kicking backwards with both feet simultaneously. They dig holes in the leaf litter and ground, which allows them to reach buried seeds or insects. They look for weed seeds, blueberries, other wild fruit and especially Polygonum (knotweed). They also look for spiders (Araneae), insects, millipedes (Diplopoda), and small snails (class Gastropoda). Nestlings are fed primarily insects.
Animal Foods: insects; terrestrial non-insect arthropods; mollusks
Plant Foods: seeds, grains, and nuts; fruit
Primary Diet: omnivore
Fox sparrows, Passerella iliaca, are found in much of northern and western North America. In the summer during their breeding season, they are found across northern Canada and Alaska, and also south through parts of western North America. During the winter they migrate towards the Pacific coast, from southern British Columbia and south to northern Baja California. They also extend across the southern area of the United States, from northern Mexico to Illinois and Connecticut.
Biogeographic Regions: nearctic (Native )
Fox sparrows commonly breed in coniferous or mixed forests, which have dense undergrowth and shrub. They also breed in woodland thickets, scrub, chaparral, and riparian woodland. During the winter months, fox sparrows are commonly found in forests, forest edges, woodlots, and other woodland habitats that have dense undergrowth.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: chaparral ; forest ; scrub forest ; mountains
Other Habitat Features: riparian
The oldest fox sparrow recovered at the Patuxent Wildlife Research Center was in 9 years and 8 months old.
Range lifespan
Status: wild: 9.6 (high) years.
Average lifespan
Status: wild: 124 months.
Fox sparrows are one of the largest of sparrows, measuring from 15 to 19 cm in length, and weighing from 26.9 to 49.0 grams. Their wingspan is typically from 26.67 to 29.85 cm and their basal metabolic rate is 66.9 cm^ oxygen per hour, on average. Fox sparrows are divided into 18 different races, all of which are large, but each looks slightly different. All fox sparrows also have a long tail and a bi-colored dark and pale yellow bill. They also have dark brown streaks on their breasts that meet at one common point. The 18 races are divided into three larger groups, including the northern and eastern birds, the southern Rocky Mountain and Sierra birds, and the northern Pacific coast birds. The eastern and northern races have a grayish head that is streaked with rust, and a red or rust rump and tail. They also have a blotchy white breast. The southern Rocky Mountain and Sierra group has a solid gray head, and also has a rust colored rump and tail. Finally, the northern Pacific coast group is very uniform and dark brown in color. Within each of the races, the individuals show no significant differences in coloration between males and females. The males are slightly larger than the females. Juvenile fox sparrows are very similar to the adults in appearance, however the upper-parts are slightly duller and the streaks on the breast are smaller and narrower.
Range mass: 26.9 to 49 g.
Average mass: 36.9 g.
Range length: 15 to 19 cm.
Range wingspan: 26.67 to 29.85 cm.
Average basal metabolic rate: 66.9 cm3.O2/g/hr.
Sexual Dimorphism: sexes alike; male larger
Other Physical Features: endothermic ; bilateral symmetry
Fox sparrows tend to be monogamous and solitary while breeding. The male usually sings in the general area of the nest, while keeping himself hidden. The sounds created are identified as call-notes, and they have not been shown to be a way to attract females, but rather are a song as a protest against intrusion into the territory by other males. These typically shy birds only become defensive when their nest territory is invaded by other birds.
Mating System: monogamous
Fox sparrows may breed up to two times a year. The breeding season is from mid-May to July. The number of eggs laid per clutch ranges from 3 to 5. The eggs are pale blue to pale green with thick brown spots. The nests of fox sparrows are typically on the ground or in very low branches. They are typically no more than 7 feet above ground. The nests are made out of twigs, dried grass, stems, and bark. The cup shaped nest is lined with grass, animal hair and feathers. It takes from 12 to 14 days for the eggs to hatch; incubation is done mostly by females. The young are typically tended to and fed by both parents. The young fox sparrows fledge in 9 to 10 days after hatching. While there was no specific information on time to independence for this species, the time to independence for sparrows in general is about 10 days. On average, both sexes of fox sparrows reach reproductive maturity when they are about 1 year old.
Breeding interval: Fox Sparrows may breed up to two times a year.
Breeding season: Fox Sparrows breed from mid-May to July
Range eggs per season: 3 to 5.
Range time to hatching: 12 to 14 days.
Range fledging age: 9 to 10 days.
Average time to independence: 10 days.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; oviparous
Average birth mass: 2.7 g.
Average eggs per season: 4.
Fox sparrows are altricial. The eggs hatch after about 12 to 14 days (females do most of the incubation), and the young fledge about 9 to 10 days later. Fox sparrows are tended to by both parents. They provide food (mainly insects) and protection. While there was no specific information on time to independence for this species, the time to independence for sparrows in general is about 10 days. Both parents will use the broken-wing display to protect their young from predators.
Parental Investment: no parental involvement; altricial ; pre-hatching/birth (Protecting: Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)
A large (6 ¾ -7 ½ inches) bunting, the Fox Sparrow is most easily identified by its reddish-brown back, streaked breast, and gray face. Other field marks include a large conical bill, long tail, and white throat patch. Male and female Fox Sparrows are similar in all seasons. The Fox Sparrow breeds across Alaska and central Canada. In the west, this species’ range extends south at higher elevations into the United States as far south as southern California. In winter, this species migrates south to the Pacific coast from Washington south to Baja California, the eastern U.S., and parts of the desert southwest. Fox Sparrows breed in a variety of thick shrubby woodland habitats, particularly those with low willow, fir, and spruce bushes. During the winter, this species may be found in thickets in shrub lands and along woodland edges. Fox Sparrows primarily eat insects in summer, adding seeds and grains to their diets during the winter. In appropriate habitat, Fox Sparrows may be observed foraging for food on the ground below shrubs and small trees. Birdwatchers may also listen for this species’ song, a series of whistles and trills that is softer and more fluid than that of the Song Sparrow (Melospiza melodia). Fox Sparrows are most active during the day, but, like many migratory songbirds, this species migrates at night.
A large (6 ¾ -7 ½ inches) bunting, the Fox Sparrow is most easily identified by its reddish-brown back, streaked breast, and gray face. Other field marks include a large conical bill, long tail, and white throat patch. Male and female Fox Sparrows are similar in all seasons. The Fox Sparrow breeds across Alaska and central Canada. In the west, this species’ range extends south at higher elevations into the United States as far south as southern California. In winter, this species migrates south to the Pacific coast from Washington south to Baja California, the eastern U.S., and parts of the desert southwest. Fox Sparrows breed in a variety of thick shrubby woodland habitats, particularly those with low willow, fir, and spruce bushes. During the winter, this species may be found in thickets in shrub lands and along woodland edges. Fox Sparrows primarily eat insects in summer, adding seeds and grains to their diets during the winter. In appropriate habitat, Fox Sparrows may be observed foraging for food on the ground below shrubs and small trees. Birdwatchers may also listen for this species’ song, a series of whistles and trills that is softer and more fluid than that of the Song Sparrow (Melospiza melodia). Fox Sparrows are most active during the day, but, like many migratory songbirds, this species migrates at night.
The fox sparrow (Passerella iliaca) is a large New World sparrow. It is the only member of the genus Passerella, although some authors split the species into four (see below).
More specific information regarding plumage is available in the accounts for the various taxa.
Adults are among the largest sparrows, heavily spotted and streaked underneath. All feature a messy central breast spot though it is less noticeable on the thick billed and slate-colored varieties. Plumage varies markedly from one group to another.
Measurements[2]:
These birds forage by scratching the ground, which makes them vulnerable to cats and other predators, though they are generally common. Fox sparrows migrate on the west coast of the United States.
They mainly eat seeds and insects, as well as some berries. Coastal fox sparrows may also eat crustaceans.
Fox sparrows nest in wooded areas across northern Canada and western North America from Alaska to California. They nest either in a sheltered location on the ground or low in trees or shrubs. A nest typically contains two to five pale green to greenish white eggs speckled with reddish brown.[3]
The review by Zink & Weckstein (2003),[4] which added mtDNA cytochrome b, NADH dehydrogenase subunit 2 and 3, and D-loop sequence, confirmed the four "subspecies groups"[5] of the fox sparrow that were outlined by the initial limited mtDNA haplotype comparison (Zink 1994).[6] These should probably be recognized as separate species, but this was deferred for further analysis of hybridization. Particularly the contact zones between the slate-colored and thick-billed fox sparrows which are only weakly distinct morphologically were of interest; the other groups were found to be distinct far earlier.[7] A further study of the nuclear genome, using microsatellites, showed similar separation between the four groups.[8]
The combined molecular data is unable to resolve the interrelationship of the subspecies groups and of the subspecies in these, but aids in confirming the distinctness of the thick-billed group.[4] Biogeography indicates that the coastal populations were probably isolated during an epoch of glaciation of the Rocky Mountains range, but this is also not very helpful in resolving the remaining problems of within-group diversity, and inter-group relationships.
Major taxonomic authorities currently differ in their treatment of the fox sparrow complex. The IOC World Bird List/Birds of the World: Recommended English Names and the HBW and BirdLife International Illustrated Checklist of the Birds of the World treat each of the four subspecies groups as a separate species, while eBird/The Clements Checklist of Birds of the World and The Howard and Moore Complete Checklist of the Birds of the World currently treat the complex as a single species.[9]
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The fox sparrow (Passerella iliaca) is a large New World sparrow. It is the only member of the genus Passerella, although some authors split the species into four (see below).
