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 )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: BREEDING: western and northern Alaska, northern Yukon, Mackenzie, southwestern Keewatin, northern Manitoba, northern Ontario, northern Quebec, and northern Labrador south along the Pacific coast to northwestern Washington, in the western mountains to southern California, Nevada, Utah, and Colorado, and, east of the Rockies, to central Alberta, central Saskatchewan, central Manitoba, central Ontario, southern Quebec, New Brunswick, Nova Scotia, and Newfoundland (AOU 1983). Breeding strongly suspected in Sierra San Pedro Martir, Baja California (Erickson and Wurster 1998). NON-BREEDING: southern Alaska and southern British Columbia southward through Pacific states to northern Baja California, and from Arizona, New Mexico, Kansas, Iowa, Wisconsin, Indiana, southern Ontario, southwestern Quebec, New Brunswick, Nova Scotia, and southern Newfoundland south to northern Sonora (casually), New Mexico, Texas, Gulf coast, and Florida (AOU 1983).

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 cm^3 oxygen/hour.

Sexual Dimorphism: sexes alike; male larger

Length: 18 cm

Weight: 32 grams

• Terrestrial

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

Comments: Dense thickets in coniferous or mixed woodlands, chaparral, parks, and gardens, wooded bottomlands along rivers and creeks. Requires dense brushy cover during the nesting season.

May nest on ground or in shrubs and trees. Nest usually at height below 2 m.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Mostly a long-distance migrant; moves northward in March-April. Migrations more localized on west coast.

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

Comments: Forages on the ground for seeds (e.g., smartweed, ragweed). Also eats berries (e.g., blueberries, elderberries) grapes and other fruits. May eat invertebrates (e.g., beetles, spiders, millipedes and crane flies).

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).

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:

• hawks (Accipitridae)
• mammalian carnivores (Carnivora)
• snakes (Serpentes)

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

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 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: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization

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)

Clutch size 3-5. Incubation 12-14 days, mostly by female (Terres 1980).

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

Canada

Rounded National Status Rank: N5B - Secure

United States

Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding

Rounded Global Status Rank: G5 - Secure

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

Comments: Composed of four groups which may represent distinct species: ILIACA (Red Fox-Sparrow), UNALASCHCENSIS (Sooty Fox-Sparrow), SCHISTACEA (Slate-colored Fox-Sparrow), and MEGARHYNCHA (Thick-billed Fox-Sparrow) (AOU 1998). Burns and Zink (1990) found that populations from the Sierra Nevada-Cascade axis, Transverse Range (southern California), Great Basin, and Rocky Mountains are genetically homogeneous. Zink (1994) examined rangewide geographic variation in mtDNA restriction sites and reported the following results. Haplotypes fall into four phylogeographic groups that correspond to groups defined by plumage characters. Within each group, these is little geographic variation in mtDNA restriction sites, but there is geographic variation in plumage coloration and body size. Hybridization is limited between between all pairs of groups except "P. MEGARHYNCHA" and "P. SCHISTACEA," for which mtDNA evidence suggests a narrow contact zone along the interface of the Great Basin and Sierra Nevada/Cascades. Morphometric characters intergrade over a broader area, suggesting that different processes are responsible for the two gradients. The number of biological species represented ranges from one to four, depending on the degree of hybridization tolerated. The mtDNA and plumage characters suggest four phylogenetic species: P. ILIACA, P. MEGARHYNCHA, P. UNALASCHCENSIS, AND P. SCHISTACEA. Rising (1996) listed three species: P. ILIACA (Red Fox Sparrow), P. UNALASCHCENSIS (Sooty Fox Sparrow), and P. SCHISTACEA (Slate-colored Fox Sparrow).