American tree sparrow

The American tree sparrow (Spizelloides arborea), also known as the winter sparrow,^[2] is a medium-sized New World sparrow.

American tree sparrow
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Passeriformes
Family:	Passerellidae
Genus:	Spizelloides Slager & Klicka, 2014
Species:	S. arborea
Binomial name
Spizelloides arborea (Wilson, 1810)
Range map of Spizelloides arborea   Breeding   Migration   Nonbreeding
Synonyms
Spizella monticola Spizella arborea Passerella arborea

American tree sparrow in Central Park

Taxonomy

In 2014, the American tree sparrow was moved to its own monotypic genus, Spizelloides, from genus Spizella, based on polyphyly in Spizella and multilocus molecular evidence suggesting the species was strongly divergent from other extant genera.^[3][4]

Description

The bird's measurements are as follows:^[5]

• Length: 5.5 in (14 cm)
• Weight: 0.5–1.0 oz (13–28 g)
• Wingspan: 9.4 in (24 cm)

Adults have a rusty cap and grey underparts with a small dark spot on the breast. They have a rusty back with lighter stripes, brown wings with white bars and a slim tail. Their face is grey with a rusty line through the eye. Their flanks are splashed with light brown. They are similar in appearance to the chipping sparrow.

Distribution and habitat

Their breeding habitat is tundra or the northern limits of the boreal forest in Alaska and northern Canada. They nest on the ground. American tree sparrows migrate into southern Canada and the United States to spend the winter.

Diet and behavior

These birds forage on the ground or in low bushes, often in flocks when not nesting. They mainly eat seeds and insects, but also eat some berries. They are commonly seen near feeders with dark-eyed juncos.

Nesting and breeding

American Tree Sparrows typically nest on or near the ground. The nest is composed of fine grasses, feathers, mosses, twigs and strips of bark.^[6]   

Despite laying one egg per day over a week, the hatching of the chicks is syncronized to within a few hours of each other. Because of this, all the chicks fledge and forage together. ^[7] Breeding pairs do not stay together after the season.^[8]

Call

This bird's song is a sweet high warble descending in pitch and becoming buzzy near the finish.