Junco hyemalis

A medium-sized (5 ½ - 6 ¾ inches) bunting, the Dark-eyed Junco comprises several geographic races possessing different patterns of plumage coloration. The eastern “Slate-colored Junco” is slate gray above and white below. The northwestern “Oregon Junco” is black on the head and breast with a chestnut back, gray wings, and white belly. The southern Rocky Mountains “Gray-headed Junco” is light gray on the head, breast, and tail with a chestnut back. The western Plains “White-winged Junco” is similar to the eastern race, but has strong white wing bars. Another race, the northern Rocky Mountains “Pink-sided Junco” is similar to the northwestern race, but is lighter gray on the head, wings, and tail. These races interbreed where their ranges overlap, producing hybrid birds with intermediate plumage. All races of this “snowbird” have in common a pale bill, dark eyes, and white feathers on the outer tail. Female Juncos are similar to males in the same race, but are usually paler and duller. The Dark-eyed Junco breeds across much of Alaska, Canada, and the northern United States, extending southwards at higher elevations to northern Georgia in the east and to Texas in the west. Dark-eyed Juncos are present all year in southern portions of this species’ breeding range, but birds breeding in these areas are displaced southward by more northern birds during winter, when this species may be found across southern Canada, the U.S., and northern Mexico. Dark-eyed Juncos breed in a variety of habitats across this species’ extensive breeding range, all of which have in common cool summer temperatures and some form of forest cover. During the winter, this species inhabits forest edges and other semi-open habitats, and will often enter urban or suburban areas where food is plentiful. Dark-eyed Juncos eat a variety of seeds and other plant material, but will also eat insects when available. In appropriate habitat, Dark-eyed Juncos may be most easily seen foraging for food on the ground or in the branches of trees. In winter, this species may be seen foraging as part of large flocks containing multiple species of sparrows and buntings. Dark-eyed Juncos are most active during the day, but, like many migratory songbirds, this species migrates at night.

Threat Status: Least concern

Dark-eyed juncos (Junco_hyemalis) breed from Alaska and central Yukon to Labrador and Newfoundland, south to central coastal California, in the mountains to eastern California, central Arizona, and western Texas, southern Alberta, northern and east-central Minnesota, central Michigan, southern New England, and in the Appalachian Mountains to northern Georgia and northwestern South Carolina; also in the Black Hills. This species winters from central and south coastal Alaska, coastal British Columbia and across southern Canada south to Mexico, the Gulf Coast and northern Florida. It is found only in the Nearctic region of the world.

Biogeographic Regions: nearctic (Native )

The subspecies insularis is endemic to Guadalupe Island, 280 km west of Baja California, Mexico, where it was once common and among the island's most abundant birds. It is now patchily distributed in the north of the island.

Dark-eyed juncos (Junco hyemalis) breed from Alaska and central Yukon to Labrador and Newfoundland, south to central coastal California, in the mountains to eastern California, central Arizona, and western Texas, southern Alberta, northern and east-central Minnesota, central Michigan, southern New England, and in the Appalachian Mountains to northern Georgia and northwestern South Carolina; also in the Black Hills. This species winters from central and south coastal Alaska, coastal British Columbia and across southern Canada south to Mexico, the Gulf Coast and northern Florida. It is found only in the Nearctic region of the world.

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: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Breeding range extends from Alaska eastward across central Canada to Labrador and Newfoundland, south to northern Baja California, Arizona, western Texas, southern Saskatchewan, southern Manitoba, Great Lakes region, and southern New England, and in the Appalachian Mountains to northern Georgia (Nolan et al. 2002). Winter range extends from southern Canada south through the United States to Florida, southern Texas, and northern Mexico.

Dark-eyed juncos are small birds that are 12.5 to 16.5 cm long. They weigh about 19 g and have a wingspan of about 23.5 cm. They have a dark gray head, back and breast and a very white belly. Their tails are dark gray on the middle feathers and white on the outside feathers. Dark-eyed juncos have a pink bill and dark eyes.

Female dark-eyed juncos are a little bit smaller and browner than males. Young juncos are also browner than males, and they have streaks on their breast.

Average mass: 19 g.

Range length: 12.5 to 16.5 cm.

Average wingspan: 23.5 cm.

Average basal metabolic rate: 46 cm^3 oxygen/hour.

Other Physical Features: endothermic ; bilateral symmetry ; polymorphic

Sexual Dimorphism: male larger; sexes colored or patterned differently

Average mass: 18 g.

Average basal metabolic rate: 0.2959 W.

All J. hyemalis are small and slender with an overall length of 5 to 6.5 inches (12.5 to 16.5 cm). This species has dark gray plumage on its head, breast and upper parts which are a contrast to their striking white, outer tail and white belly. Sexes are colored or patterned differently with female and immature J. hyemalis somewhat browner than the adult male; juveniles also have streaked breasts. Males are usually around 5% larger than females. Members of this species have a pink bill and dark eyes. A typical weight for J. hyemalis is 0.67 oz (19 g) and an average wingspan is 9.25 inches (23.5 cm).

Average mass: 19 g.

Range length: 12.5 to 16.5 cm.

Average wingspan: 23.5 cm.

Average basal metabolic rate: 46 cm^3 oxygen/hour.

Other Physical Features: endothermic ; bilateral symmetry ; polymorphic

Sexual Dimorphism: male larger; sexes colored or patterned differently

Average mass: 18 g.

Average basal metabolic rate: 0.2959 W.

Length: 16 cm

Weight: 2 grams

Dark-eyed juncos are found in woodlands that have openings with a dense layer of plants near the ground. They avoid going deep into forests. Instead, they prefer openings and the edges of forests and woodlands. In winter, they can be found in weedy fields, open woodlands, hedgerows, suburbs, and farmyards. They live between sea level and 3500 meters elevation.

Range elevation: 0 to 3500 m.

Habitat Regions: temperate ; polar ; terrestrial

Terrestrial Biomes: forest

Other Habitat Features: urban ; suburban ; agricultural ; riparian

Systems

The habitat of J. hyemalis occurs from sea level to timberline in a variety of woodland areas that have openings with dense herbaceous ground cover. These areas include coniferous and deciduous forests, forest edges, woodland clearings, stream borders, open woodlands, brushy cover bordering mountain meadows, and old barns. This species avoids deep forest interiors in favor of woodland edges and openings. In winter they prefer weedy fields, but also inhabit open woodlands, hedgerows, suburbs, and farmyards. They are found from sea level to 3500 meters.

Range elevation: 0 to 3500 m.

Habitat Regions: temperate ; polar ; terrestrial

Terrestrial Biomes: forest

Other Habitat Features: urban ; suburban ; agricultural ; riparian

Comments: Habitats include various sorts of coniferous, mixed, and deciduous forest; forest edge; forest clearings; bogs; open woodland; brushy areas adjacent to forest; and burned-over lands. In migration and winter the species occurs in a wide range of openly wooded and brushy and grassy habitats (AOU 1998). Nests are in scrapes on the ground and usually are concealed by logs, rocks, tree roots, leaves, or ground vegetation.

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.

Generally this species is a long-distance migrant, but migrations are more localized in some areas of the West, and the Appalachian population is largely sedentary.

South-bound migration from the northern breeding range occurs primarily September-November. Migration to northern breeding areas occurs mainly March-May.

Dark-eyed juncos eat insects, non-insect arthropods, and seeds during the fall and winter. They are often seen at bird feeders during migration and in the winter months, but they prefer to search for food on the ground. When there is snow on the ground, dark-eyed juncos scratch away a small circle of snow to look for grain. To eat grass seed, dark-eyed juncos "ride" a grass stem. They fly to a tall grass stem and hold on as the stem bends down to the ground. The junco can stand on the grass stem on the ground and eat the seeds. During the breeding season, dark-eyed juncos eat mostly insects, including caterpillars, beetles, and ants. They also eat the seeds of many weed species.

Dark-eyed juncos drink water from streams or pools or from raindrops or dew on plant leaves. During the winter, they eat snow in order to get water.

Animal Foods: insects; terrestrial non-insect arthropods

Plant Foods: seeds, grains, and nuts

Dark-eyed juncos forage on the ground, picking up a wide variety of seeds and some insects. In the non-breeding season, they prefer to feed on insects, non-insect arthropods, and seeds. During the breeding season, they eat mostly insects. They are commonly seen at bird feeders during migration and in the winter months, however, even then they prefer to feed on the ground rather than pick seeds from an elevated feeder. One method of foraging practiced by this species is "riding" a grass stem. This is accomplished by flying up onto a tall grass stem, riding the stem down to the ground as it bends under the bird's weight, and then plucking the seeds from the seed head as it sits on the ground. When a thin layer of snow lies on the ground, dark-eyed juncos scratch away a roughly circular hole, 3 or 4 inches in diameter, to get at the grain underneath. In the summer, half of the diet consists of insects. Caterpillars, beetles, and ants are the most common items in their diet. There is also a long list of mostly weed plants whose seeds J. hyemalis is known to eat. The most common are ragweed, bristlegrass, dropseed grass, crabgrass, pigweed, and goosefoot. Juncos are morphologically generalized enough to handle both seeds and insects as part of their diet.

Animal Foods: insects; terrestrial non-insect arthropods

Plant Foods: seeds, grains, and nuts

Primary Diet: omnivore

Comments: Diet includes seeds throughout the year, insects during the breeding season, and waste grain in fall and winter.

Dark-eyed juncos play an important role in their ecosystems. They disperse seeds and help to control insect populations. Brown-headed cowbirds (Molothrus_ater) sometimes lay their eggs in the nests of dark-eyed juncos. When this happens, the dark-eyed junco parents feed and protect the brown-headed cowbird chicks. Dark-eyed juncos also host many different parasites.

Ecosystem Impact: disperses seeds

Dark-eyed juncos are killed by many different birds, including Accipiter striatus, Lanius and owls. They are also often killed by feral and domestic Felis domesticus. Red squirrels (Tamiasciurus_hudsonicus), weasels (genus Mustela), chipmunks (genus Tamias), American martens (Martes_americana) and other mammals as small as Zapus trinotatus take eggs and young from nests.

When a predator approaches, dark-eyed juncos hide under whatever is nearby. If a predator comes near a nest, parents make "chip" sounds and fly around the nest area. They sometimes even dive at predators.

Known Predators:

• sharp-shinned hawks (Accipiter_striatus)
• chipmunks (Tamias)
• red squirrels (Tamiasciurus_hudsonicus)
• shrikes (Lanius)
• weasels (Mustela)
• American martens (Martes_americana)
• owls (Strigiformes)
• feral cats (Felis_silvestris)
• domestic cats (Felis_silvestris)

Dark-eyed juncos, like many other bird species, are an integral part of forested ecosystems and play an important role in maintaining the health and productivity of the forests and woodlands. Members of this species aid in the dispersal of seeds and help to control insect populations. They are occasionally parasitized by brown-headed cowbirds (Molothrus ater). Antibodies of the St. Louis strain of encephalitis have been reported in dark-eyed juncos and there are 26 other genera of parasites that have been reported to use this species as a host.

Ecosystem Impact: disperses seeds

Because it inhabits open areas, Junco hyemalis is subject to attack by many different birds, including sharp-shinned hawks, shrikes and owls. They are also frequently killed by feral and domestic cats. Red squirrels (Tamiasciurus hudsonicus), weasels (genus Mustela), chipmunks (genus Tamias), American martens (Martes americana) and other mammals as small as jumping mice take eggs and young from nests.

In response to predators, adults flee to nearby shelter. Parents give "chips" excitedly and fly around nest areas when predators are present and sometimes even dive at predators attempting to prey on nestlings or eggs.

Known Predators:

• sharp-shinned hawks (Accipiter striatus)
• chipmunks (Tamias)
• red squirrels (Tamiasciurus hudsonicus)
• shrikes (Lanius)
• weasels (Mustela)
• American martens (Martes americana)
• owls (Strigiformes)
• feral cats (Felis silvestris)
• domestic cats (Felis silvestris)

Junco hyemalis is prey of:
Mustelinae
Accipiter striatus
Accipiter gentilis
Accipiter
Tamias
Mustela
Lanius excubitor
Tamiasciurus hudsonicus
Martes americana

Based on studies in:
USA: Arizona (Forest, Montane)

This list may not be complete but is based on published studies.

Junco hyemalis preys on:
shrubs
grass
herbs
Coleoptera
Insecta
ground invertebrates
Arthropoda

Based on studies in:
USA: Arizona (Forest, Montane)

This list may not be complete but is based on published studies.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: This species is represented by a very large number of occurrences (subpopulations).

>1,000,000 individuals

Comments: Total adult population size is unknown but certainly exceeds 1,000,000. Rich et al. (2004) estimated population size at 260,000,000.

Dark-eyed juncos have many different songs. Their most common song is a simple, musical trill. Only male dark-eyed juncos sing. To show that they own a territory, males use a warbling song. They use different calls when they are alarmed or when fighting or scolding another.

Dark-eyed juncos also use physical displays to show ownership of a territory and to attract a mate.

Communication Channels: visual ; acoustic

Dark-eyed juncos (Junco hyemalis) possess considerable variation in song. The most common song is a simple, musical trill, all in one pitch, or a series of rapid notes which may be too rapid to discern. Only male dark-eyed juncos sing. To proclaim occupancy of a territory, two or three trills on different pitches may be joined to form a single warbling song. A simple explosive call is used as an alarm, while a smacking sequence is used to scold. This species uses a combination of twanging, buzzing, and smacking notes when fighting.

Junco hyemalis also uses territorial and courtship displays to communicate (see Mating Systems and Behavior).

Communication Channels: visual ; acoustic

Dark-eyed juncos usually live between 3 and 11 years. The oldest known wild dark-eyed junco lived at least 11 years and 1 month. Most juncos probably die due to predation by other species (hawks, squirrels, weasels, etc.).

Range lifespan
Status: wild: 11.1 (high) years.

Typical lifespan
Status: wild: 3 to 11 years.

The average lifespan of J. hyemalis is approximately 3 to 11 years. The oldest known wild dark-eyed junco lived at least 11 years 1 month. Most commonly, predation by other species (hawks, squirrels, weasels, etc.) limits their lifespan.

Range lifespan
Status: wild: 11.1 (high) years.

Typical lifespan
Status: wild: 3 to 11 years.

Maximum longevity: 11.3 years (wild) Observations: In the wild, these animals can live up to 11.3 years (Blumstein and Moller 2008).

Dark-eyed juncos are monogamous. Males arrive at the breeding grounds very early in the spring. They claim a territory by singing from the top of the tallest trees in a 2 to 3 acre area. When a female enters a territory, the male follows her around. He spreads his tail and wings and struts around the female, making "chip" sounds and singing. He may move his tail up and down to show off his white feathers to the female. Males and females form pairs by mid-April. The males follow their mates around and usually stay within 50 feet of the female.

Mating System: monogamous

Dark-eyed juncos begin breeding in April. The female builds the nest and the male helps by bringing nest material. Nests are usually built on the ground near the edge of a forest opening. They are usually hidden under plants, logs, tree roots, or other shelters. Nests are sometimes built in a tree or shrub up to 8 feet above the ground. They are built of sticks, leaves and moss, and are lined with soft materials, like grasses, mosses or mammal hair. Each nest can be used to raise two or three broods in one season.

The female lays 3 to 6 white or greenish eggs with brown spots. The eggs are usually slightly glossy and about 19 mm long. The female incubates the eggs for 12 to 13 days. The chicks are helpless when they hatch, but they are able to leave the nest after 9 to 13 days. The parents feed the chicks while they are in the nest and for about 3 weeks after they have left the nest. Most dark-eyed juncos begin breeding when they are 1 year old.

Breeding interval: May breed 2 to 3 times during the spring and early summer each year

Breeding season: Dark-eyed juncos begin breeding in April

Range eggs per season: 3 to 6.

Average eggs per season: 4.

Average time to hatching: 12 to 13 days.

Range fledging age: 9 to 13 days.

Range time to independence: 9 to 21 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 time to hatching: 11 days.

Average eggs per season: 4.

The female parent incubates the eggs and broods the chicks after they hatch. Both parents defend the nest from predators and clean the nest by removing fecal sacs. They also feed the chicks regurgitated food and soft insects, such as caterpillars.

Chicks are helpless (altricial) when they hatch. Their eyes begin to open after 2 days and they begin to grow feathers after 7 days. They develop strong leg muscles before they can fly so that they can run away from predators. They leave the nest after 9 to 13 days. The parents still feed the chicks for about 3 weeks after they leave the nest. If chicks beg from their parents after 3 weeks, the parents will chase them away.

Parental Investment: no parental involvement; altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female)

Dark-eyed juncos are monogamous. Males usually arrive on breeding grounds in the spring, well in advance of the start of nesting, and pairs are formed by mid-April. Males claim territories by singing from the top of the tallest trees in a 2 to 3 acre area. When a female enters his territory, the male pursues her aggressively. He spreads his tail and struts around the female, uttering "chips" and songs. The male may alternate dropping his tail to the ground with lifting it at a 45 degree angle. Once a pair is formed, males follow their mates and are seldom more than 50 feet away. The only exception is when the male proclaims his occupancy of a territory from a high perch.

Mating System: monogamous

The breeding season for dark-eyed juncos begins in April. Females build the nest over a period of 1 to 9 days, but the male often helps by bringing nest material. Nests are commonly built on the ground near the edge of openings in wooded areas or in a slight depression. They are usually well concealed under weeds, grasses, fallen logs, tree roots, or other overhead shelter. Nests are occasionally built up to 8 feet above ground in a shrub or tree. The nest cup is often lined with fine grasses, mosses or mammal hair and is used for two or three broods in one season.

The female lays 3 to 6 white or pale green eggs spotted with brown. The eggs are usually ovate and slightly glossy. Average egg size is about 0.8 inches (19 mm). The incubation period lasts 12 to 13 days; incubation is usually done by the females. Chicks leave the nest 9 to 13 days after hatching. After leaving the nest, the young remain at least partially dependent on their parents for about 3 weeks. Most dark-eyed juncos begin breeding at at 1 year.

Breeding interval: May breed 2 to 3 times during the spring and early summer each year

Breeding season: Dark-eyed juncos begin breeding in April

Range eggs per season: 3 to 6.

Average eggs per season: 4.

Average time to hatching: 12 to 13 days.

Range fledging age: 9 to 13 days.

Range time to independence: 9 to 21 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 time to hatching: 11 days.

Average eggs per season: 4.

The female parent incubates the eggs and broods the chicks after they hatch. Both parents defend the nest from predators, remove fecal sacs from the nest and feed the chicks regurgitated or partly digested food along with an occasional tender caterpillar. Chicks are altricial and begin to open their eggs at the end of the second day. Their feathers begin to show around the seventh day. Rapid tarsal development enables nestlings to run from the nest if threatened before they can fly. Youngsters leave the nest 9 to 13 days after hatching. After leaving the nest, the young remain at least partially dependent on their parents for food for about 3 weeks. Occasionally, young will attempt to solicit parental care and crouch in a begging posture even after they are adequately developed for independence. Parents become aggressive in these cases and chase the fledgling a short distance without feeding it.

Parental Investment: no parental involvement; altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female)

In most areas, nesting occurs from April to as late as August, but earlier nesting may occur in southern lowland areas and fledging may sometime extend into September. Clutch size usually is 3-5. Incubation lasts about 11-12 days. Both parents feed nestling and newly fledged young.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 59 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 60
Specimens with Barcodes: 63
Species With Barcodes: 1

Dark-eyed juncos are protected under the US Migratory Bird Treaty Act. They are very common birds.

IUCN Red List of Threatened Species: least concern

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2008
  Least Concern
• 2004
  Not Recognized
• 2000
  Not Recognized
• 1994
  Not Recognized
• 1988
  Not Recognized

Dark-eyed juncos are protected under the US Migratory Bird Treaty Act. They are quite abundant within their geographic range.

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,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Large range in North America; very large population size; many occurrences; apparently slowly declining.

Global Short Term Trend: Relatively stable to decline of 30%

Comments: BBS data suggest that the species has declined slowly over the past 10 years or three generations.

Global Long Term Trend: Decline of 30-50%

Comments: Long-term decline over the past 200 years is unknown. Breeding Bird Survey (BBS) data for 19662007 indicate a signidicant survey-wide decline of 1.3% per year; this amounts to a 42% decline over this time period. BBS abundance (average number of bird per route) declined from roughly 8-9 in the 1960s and 1970s to around 6 in 2000-2007. Overall, based on BBS data, the species appears to have undergone a slow but steady decline in abundance over the past several decades.

Degree of Threat: Low

Comments: No major threats have been identified. Causes of the slow, apparently ongoing decline are not known.

Major Threats

Conservation Actions

Global Protection: Very many (>40) occurrences appropriately protected and managed

Comments: Many occurrences are in protected areas.

There are no known adverse affects of dark-eyed juncos on humans.

Dark-eyed juncos do not really affect humans, though many people enjoy photographing them or watching them at bird feeders. They also eat some insects that are pests.

Positive Impacts: controls pest population

There are no known adverse affects of dark-eyed juncos on humans.

Junco hyemalis has little, if any, economic importance for humans. This species is an excellent subject for photography and art and provides an enjoyable pastime for many bird watchers. Due to the fact that they are commonly found at bird feeders during migration and winter months, they may play a small part in the sale and production of bird seed, bird feeders and binoculars. Juncos also eat insects that humans may consider pests.

Positive Impacts: controls pest population