Hermit thrushes (Catharus guttatus) are widely distributed songbirds found in northern hardwood forests and boreal and mountainous coniferous forests throughout North America during the breeding season, and both North America and Central America during the winter. In North America, they breed in the western and northeastern United States into Alaska and much of the southern half of Canada. The winter northern boundary is in the United States from southern Massachusetts moving gradually southwest to the southern parts of Ohio, Indiana, Illinois, Arkansas, most of Oklahoma and Texas. Their winter range then encompasses all of the area below this to the Gulf of Mexico and then south through Mexico to Oaxaca. They are found year round in much of New Mexico and in the eastern half of Arizona. Within these broad ranges individuals are short-distance migrants. They do not cross the Gulf of Mexico as other Catharus species do. They are found in lower altitudes, river valleys and coastal areas in these wintering areas.

There are currently 8 recognized subspecies of hermit thrushes divided into 3 geographic groups including 3 subspecies in the Pacific coastal group, 3 subspecies in the northwestern interior mountains group, and 2 subspecies in the eastern group.

Biogeographic Regions: nearctic (Native ); neotropical (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: (>2,500,000 square km (greater than 1,000,000 square miles)) Breeding range extends from western and central Alaska across southern Mackenzie to southern Labrador and Newfoundland, south to southern Alaska, in the mountains to southern and eastern California, southern Nevada, central and southeastern Arizona, southern New Mexico, and western Texas; east of the Rockies to southwestern and central Alberta, central Saskatchewan, northern Minnesota, northeastern Ohio, western Virginia, western Maryland, southern New Jersey, and southern New York; also isolated breeding population in Black Hills, South Dakota (AOU 1998). Breeding also occurs in the Sierra San Pedro Martir, Baja California (Erickson and Wurster 1998). Nonbreeding range extends from southern British Columbia, northern U.S., southern Ontario and New England, south to southern Baja California, through Mexico to Guatemala and El Salvador, southern Texas, Gulf Coast, southern Florida, and the northern Bahamas (AOU 1998).

Hermit thrushes are shorter and stockier than other spotted thrushes, with an average length of 6.75 in (17.2 cm) and wingspan of 11.5 in (29.2 cm). The three main geographic groups have graded characteristics, with a distinct white eye-ring, indistinct whitish bar over the lores, darkly spotted breast and sides of the throat, olive-brown to gray-brown dorsal coloration, white ventral side with buffy to grayish flanks, and varying amount of reddish wash on flight feathers and tail. There is no obvious sexual dimorphism in this thrush species.

Hermit thrushes have reddish coloration on the tail, whereas wood thrushes (Hylocichla mustelina) have similar coloration on the head and veery (Catharus fuscescens) have reddish upper parts. Gray-cheeked (Catharus minimus) and Bicknell's (Catharus bicknelli) thrushes also have some reddish coloration, but they only have a thin partial eye-ring and do not have the whitish bar over the lores. Because hermit thrushes are short-distance migrants, their primary flight feathers do not project beyond their secondaries. Other thrushes that migrate over longer distances have longer primary projections, including the Swainson's thrush (Catharus ustulatus) and grey-cheeked thrush (Catharus minimus).

Average length: 17.2 cm.

Average wingspan: 29.2 cm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike

Average mass: 27.8 g.

Length: 17 cm

Weight: 31 grams

• Terrestrial

Hermit thrushes use a wide range of forest vegetation types. Breeding habitat includes young to climax forest vegetation types with internal forest edges. These birds are found in the interior of such forest vegetation types near openings including ponds, meadows, or small man-made clearings.

During winter in the United States, hermit thrushes are usually found at lower elevations than that of their summer habitat. Characteristics of winter habitat include a dense cover of woody plants proximate to insect populations and berry-bearing vegetation. Hermit thrushes need open water in their winter habitat. Information on habitat in Mexico is limited, and no generalizations can be made.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: forest ; scrub forest

Comments: Open humid coniferous and mixed forest and forest edge, dry sandy and sparse jackpine, less frequently in deciduous forest and thickets; in migration and winter also chaparral, riparian woodland, arid pine-oak, desert scrub. Negatively impacted by forest fragmentation in southern Wyoming (Keller and Anderson 1992). Associated with large (>24 ha) aspen groves in Saskatchewan (Johns 1993). Nests usually on ground under conifer with low branches or hidden by low plants, or in low conifer or other tree or bush within 3 m of ground.

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.

Long-distance migrant throughout Canada and most of U.S. breeding range.

Hermit thrushes are omnivores that eats insects, small invertebrates, and fruits from trees, shrubs, and herbaceous plants. They forage on both the ground and in vegetation, and may move leaf litter with their bills to look for food, glean from leaves while perched or after hovering, or probe into ground or dead wood. The proportion of animal and vegetable content in the diet of Hermit Thrushes varies with availability. Generally, hermit thrushes consume more animal matter during the spring and summer, and more vegetable matter (especially berries) in the fall and winter.

Foods commonly eaten include: beetles, bees, ants, wasps, flies, true bugs, other small invertebrates, small amphibians and reptiles, and fruits.

Animal Foods: amphibians; reptiles; insects; terrestrial non-insect arthropods; terrestrial worms

Plant Foods: fruit

Primary Diet: omnivore

Comments: Eats insects and other invertebrates mostly from ground; also eats small fruits (Terres 1980).

Commensal/Parasitic Species:

• ticks (Ixodides)
• lice (Pthiraptera)
• louse flies (Hipposboscidae)
• mites (Acari)
• spirochaetes

There is little information on predation but they probably are subject to the usual songbird nest predators (snakes, crows, jays, raccoons). Body parasites found on or in adult hermit thrushes include lice, louse flies, mites, spirochetes and ticks.

Known Predators:

• snakes (Serpentes)
• American crows (Corvus brachyrhynchos)
• blue jays (Cyanocitta cristata)
• raccoons (Procyon lotor)

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

Estimated Number of Occurrences: > 300

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

>1,000,000 individuals

Comments: Global population estimate is 56,000,000 birds (Rich et al. 2004).

A banded hermit thrush lived at least 8 years and 8 months. Other thrushes have been known to live 10 to 13 years.

Range lifespan

Status: wild: 8.55 (high) years.

Average lifespan

Status: wild: 112 months.

Males establish and defend breeding territories in late April to late May. Once a female is accepted into a male's territory, she begins building a nest. The open-cup nest is 10 to 15 cm in diameter and consists of a variety of vegetable material including grass, leaves, mosses, and lichens. Nest location is variable. In the eastern United States nests found on the ground beneath live woody and non-woody plants and in open areas, and in the western United States nests were commonly located above the ground. Females lay 3 to 6 eggs beginning in Late May, and may lay 2nd or 3rd brood as late as August. Egg color ranges from very pale blue to blue-green with few brown flecks. Females begin incubating after final egg is laid, and this period lasts around 12 days. The male feeds the female during incubation.

A hatching bird "pips" the egg, breaks its shell into 2 parts near the egg's greatest diameter. The female removes eggshells from the nest after young hatch. Young are altricial at hatching and have minimal dark grayish down on crown and dorsal feather tracts. The female feeds nestlings with food brought to the nest by the male. Nestling eyes are open by the 3rd day after hatching; full juvenile plumage develops by 10 to 12 days after hatching. Nestlings fledge 10 to 15 days after hatching by leaping from the nest towards a parent on the ground. No information on development from fledging through immature stages is available.

Brood parasitism by the brown-headed cowbird is common, but little is known on how this affects populations of the Hermit Thrush. Recruitment may be limited by nest predation, but little information is available. Studies estimating the probability of fledging at least 1 nestling varied from 17% in Arizona to 37% East of the Rocky Mountains. There is no evidence of cooperative breeding in hermit thrushes.

Breeding interval: These birds once per year, in the spring and summer.

Breeding season: May through August

Range eggs per season: 3 to 6.

Average time to hatching: 12 days.

Range fledging age: 10 to 15 days.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization (External )

Average time to hatching: 12 days.

Average eggs per season: 3.

Females incubate and deliver food to the nestlings. Males bring food to the nest.

Parental Investment: altricial ; pre-fertilization (Provisioning); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)

Clutch size usually is 3-4. Incubation, by female, lasts 12-13 days. Young are tended by both parents, leave nest at 10-12 days.

Migratory songbirds prepare for long flights by eating berries rich in antioxidants.

"Bug-chomping songbirds have been discovered doing something  remarkable before migrating south for the winter: They switch,  awkwardly, to berries rich in antioxidants.

"The dietary change has less to do with fattening up and more to do  with stocking up on nutrients to help their bodies deal with the stresses of migration, say researchers." (O'Hanlon 2010)

Breeding Bird Surveys indicate that hermit thrush populations have increased over extensive parts of their 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 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Widespread, abundant, and secure.

Global Short Term Trend: Relatively stable to increase of 25%

Global Long Term Trend: Relatively stable to increase of >25%

Comments: Breeding Bird Survey (BBS) data indicate a positive population trend throughout much of the range since 1966, possibly as a result of expansion of suitable habitat from woodland cutting (Jones and Donovan 1996). For the period 1980-2005, BBS data indicate a positive survey-wide trend of 0.8% per year (P<0.01, n = 1086; Sauer et al. 2005). Christmas Bird Count (CBC) surveys also show a survey-wide increase of 2.2% per year for the period 1965-2002 (Niven et al. 2004).

Comments: Potential threats include human-caused and natural habitat alteration or loss, effects of human intrusion, and natural causes of mortality such as predation and severe weather events. However, on a range-wide scale, this species is not significantly threatened.

Changes in abundance have been noted in response to various tree removal practices. Some researchers suggest that Hermit Thrush populations are equally stable on both logged and unlogged habitats (Webb et al. 1977, Medin 1985) and that density and productivity are higher in younger stands (Rangen et al. 2000). Others suggest that breeding densities are higher in unlogged habitats (Franzreb and Ohmart 1978, Medin and Booth 1989, Jones and Donovan 1996, Hanowski et al. 2003).

Hermit Thrush densities have decreased following wildfires. Declines resulted both immediately (Apfelbaum and Haney 1981) and several years post- burn (8 years later; see sources in Jones and Donovan 1996).

Habitat fragmentation and the resultant increase in edge habitats may negatively affect nesting success due to increased predator abundance and activity along edges (Manolis et al. 2002). Hames (1999) reported that as forest habitat fragmentation increased, nesting attempts decreased throughout the species' North American range.

Martin and Roper (1988, in Jones and Donovan 1996) suggested that disturbance by researchers did not impact thrush nesting behavior or success in Arizona, but Gutzwiller and Anderson (1999) reported that low levels of human intrusion increased displacement of thrushes and resulted in lower abundance than prior to intrusion events in the Snowy Mountains, Wyoming.

Biological Research Needs: Research needed on breeding biology, including estimation of adult and juvenile survival and nest success in different habitats; basic nesting information such as number of broods, offspring and nest attempts per year; fidelity to natal, breeding, and wintering sites; and determination of subspecies validity using studies of geographic dispersal and genetic or morphological characteristics (Jones and Donovan 1996). However, effective conservation of this species does not depend on this research.

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

Comments: This species occurs in many protected area such as national parks and wilderness areas.

There are no known adverse effects of Hermit Thrushes on humans.

Comments: This species formerly was placed in genus Hylocichla (AOU 1983). Systematics are complex and have little consensus. Several subspecies are recognized by various authors. The American Ornithologists' Union (1957) and Ripley (1964) recognized eight subspecies, Aldrich (1968) recognized 10 subspecies, and Phillips (1991) recognized 13 (see Jones and Donovan 1996). Subspecies vary morphologically, especially in wing, tail, and tarsus length, and plumage coloration; bill length increases from north to south of range, tarsus length decreases from north to south (Aldrich 1968). Three generally recognizable groups include birds occurring east of the Rocky Mountains, central Alaska south through the Sierra Nevada and Rocky Mountains, and west and north of the Sierra Nevada-Cascade ranges along the Pacific coast (Lane and Jaramillo 2000).