Varied Thrush

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Image:VariedThrush.JPG

Common Name: Varied Thrush
Scientific Name: Ixoreus naevius

Size: 7.5-10.2 inches (19-24 cm); Wingspan: 13.4-15 inches (34-38 cm)

Habitat: North America; found in the Pacific Northwest. In its breeding range, which covers Alaska and tapers as it extends south to northern California. It is a short-distance, partial migrant. Some coastal breeders stay in one place year-round, but inland breeders migrate south in winter. Northern breeding populations may “leapfrog” past southern breeding populations, wintering farther south (as far as Baja California). In many winters, a few Varied Thrushes move erratically and appear in the Midwest and Northeast, far out of their normal range.

It’s preferred habitat is the dark and wet mature forests in the Pacific Northwest; forests dominated by coastal redwood, Sitka spruce, red alder forests, western hemlock, western red cedar, western larch, or Douglas-fir. In winter it may be found in a broader range of habitats, including parks, gardens, lakeshores, and riparian areas where fruit and berries are abundant.

Status: Not Threatened. Global population: Unknown population. Varied Thrushes are fairly common, but their populations may be declining in Idaho, Washington, the Cascade Mountains, and the wet forests of the Oregon and California coasts. Because they live in mature and old-growth forests containing very large trees, logging and forest fragmentation can cause habitat loss that reduces their numbers. They don’t tend to live in forest patches smaller than about 40 acres. Around human habitation, Varied Thrushes have proven very vulnerable to window strikes as well as predation by domestic and feral cats and collisions with cars. Varied Thrushes may benefit from reserves that have been established to protect the Northern Spotted Owl.

Diet: Insects, nuts and berries. During breeding season, Varied Thrushes eat insects and other arthropods from the leaf litter; in winter they eat mostly berries and nuts. They forage by seizing dead leaves in their bill and hopping backward to clear a spot of ground before examining it for prey. In fall and winter, they switch to fruits and acorns, forming loose flocks around their food. Some of their typical fruits are snowberry, apple, honeysuckle, madrone, mistletoe, manzanita, toyon, ash, salal, cascara, dogwood, blueberry, huckleberry, salmonberry, and thimbleberry.

Varied Thrushes are often aggressive toward each other and other bird species. At feeders, males sometimes defend small feeding territories, where they dominate sparrows, blackbirds, cowbirds, towhees and juncos. They usually defer to California Quails, Northern Flickers, Western Scrub-Jays, and American Robins. The only time Varied Thrushes flock with other species is when they occasionally forage for berries or earthworms on lawns with American Robins.

Nesting: Males are dark blue-gray on the back and rich burnt-orange below with a sooty-black breast band and orange line over the eye. The wings are blackish with two orange bars and orange edging to the flight feathers. Females have the same patterns, but are paler gray-brown than males. Immatures are generally brown, though its stomach feathers are white, and initially harbors two orange stripes at the covert feathers.

They are thought to establish monogamous breeding pairs, but how long the birds stay together is not known. Females probably choose where to build the nest—usually in the understory of a mature forest, often in a spot surrounded by old nests (or even directly on top of one). They are usually around 10 feet off the ground and poorly concealed, close to the trunk of a small conifer.

The female gathers nest material and weaves an outer layer of fir, hemlock, spruce, or alder twigs. She adds a middle layer with rotten wood, moss, mud, or decomposing grass, which hardens into a dense cup about 4 inches across and 2 inches deep. Finally, she lines the cup with fine grasses, soft dead leaves, and fine moss, and drapes pieces of green moss over the rim and outside of the nest.

The eggs are light blue, sometimes with dark-brown speckles in colors and the incubation time lasts 12 days. The nesting period is 13-15 days.

Cool Facts: Varied Thrushes forage on the ground, periodically moving to higher perches in the understory to sing or move between foraging sites. Males reach the breeding grounds before females and start singing to establish territories. They have several threat displays, beginning by cocking the tail, turning it toward an intruder, and lowering the wings. If the adversary remains, the displaying bird will face off, lowering its head, raising and fanning the tail, and spreading its wings out to its side. Occasionally, males peck at or lock bills with each other. While squabbling over territory or chasing away nest intruders, they may dive and swoop through dense vegetation, sometimes hitting branches along the way. Males may also defend small sites around bird feeders in the winter, though females seem to use alternative feeding sites to avoid competition.

There is an extremely rare variant of this species in which all the orange in the plumage is replaced by white. A very rare British vagrant in 1982 was of this type, leading to speculation that whatever mutation causes the color variation also affects the navigational abilities of this thrush. There have been only five recorded sightings since 1921.

The oldest Varied Thrush on record was 4 years, 9 months old.


Found in Songbird Remix Woodland Jewels

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