Hermit Thrush (Catharus guttatus)

[order] PASSERIFORMES | [family] Turdidae | [latin] Catharus guttatus | [UK] Hermit Thrush | [FR] Grive solitaire | [DE] Einsiedlerdrossel | [ES] Zorzalito Colirrufo | [NL] Heremietlijster

Subspecies

Physical charateristics

Hermit thrushes are shorter and stockier than other spotted thrushes, with an average length of 17 cm and wingspan of 29 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.

Listen to the sound of Hermit Thrush

[audio:http://www.aviflevoland.nl/sounddb/H/Hermit Thrush.mp3]

Copyright remark: Most sounds derived from xeno-canto

Range

North America : widespread

Habitat

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.

Reproduction

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.

Feeding habits

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.

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

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.

Migration

The Hermit Thrush is the only spot-breasted thrush likely to be seen in the United States in the winter. Those that do migrate arrive earlier in the spring (March-May) and leave later in the fall (September-October) than the other thrushes. These birds migrate mostly at night and spend the winter in the southern part of the United States through Mexico to Guatemala.

Distribution map