The lesser goldfinch (Spinus psaltria) is a small finch in the genus Spinus native to the Americas.

As is the case for most species in the genus Spinus, lesser goldfinch males have a black forehead, which females lack. Males in this species vary strikingly in the color of their back across their range, from green in western North America to black in the eastern Rocky Mountains and Texas south to northern South America; this variation has resulted in five subspecies being recognized.

Taxonomy

thumb|left|S. p. hesperophilus

Together with its relatives the American goldfinch and Lawrence's goldfinch, it forms a clade, termed the 'New World goldfinch' clade, in the genus Spinus. Some authors have suggested treating this clade as a separate genus Astragalinus, but this has not been followed by either the IOC or BirdLife International. The specific epithet psaltria is Ancient Greek for a female harpist. The type locality is Colorado Springs, Colorado. The lesser goldfinch is now placed in the genus Spinus that was introduced in 1816 by the German naturalist Carl Ludwig Koch.

Five subspecies are currently recognized,

  • S. p. hesperophilus (Oberholser, 1903) – west USA and northwest Mexico
  • S. p. witti Grant, PR, 1964 – Tres Marias Islands (off west Mexico)
  • S. p. psaltria (Say, 1822) – west-central USA to south-central Mexico
  • S. p. jouyi (Ridgway, 1898) – southeast Mexico and northwest Belize
  • S. p. colombianus (Lafresnaye, 1843) – south Mexico to Peru and Venezuela

Description

This species is not only the smallest North American Spinus finch, it may be the smallest true finch in the world. Some sources list more subtropical Spinus species as slightly smaller on average, including the Andean siskin (Spinus spinescens). This species ranges from in length and can weigh from . Among standard measurements, the wing chord is , the tail is , the bill is and the tarsus is . require more study, especially since at least the former two also seem to be significantly larger and longer-billed. Another distinctive call is a very high-pitched, drawn-out whistle, often rising from one level pitch to another (teeeyeee) or falling (teeeyooo). The song is a prolonged warble or twitter, more phrased than that of the American goldfinch, often incorporating imitations of other species.

<gallery mode=packed heights=150px>

♂ lesser goldfinch.jpg|Intermediate male;<br/>note mottled back and cap

Lesser goldfinch (Spinus psaltria colombianus) male Cundinamarca.jpg|male S. p. colombianus, Colombia

Spinus psaltria.webm|S. p. hesperophilus at Desert Botanical Garden, Phoenix

</gallery>

Distribution and habitat

This goldfinch ranges from the southwestern United States to as far north as the Columbia River in Washington and south to Venezuela and Peru. It seasonally migrates out of parts of its U.S. range, but is resident year-round in others, and has rapidly expanded across much of the Pacific Northwest in recent decades as a year-round resident.

The lesser goldfinch often occurs in flocks or at least loose associations. It utilizes almost any habitat with trees or shrubs except for dense forest, and is common and conspicuous in many areas, often coming near houses. It is common at feeders in the Southwest United States and will come almost anywhere with thistle sock feeders. Flocks of at least six birds will often be seen at feeders. It feeds mostly on tree buds and weed seeds; geophagy has been observed in this species.

The nesting season is in summer in the temperate parts of its range; in the tropics it apparently breeds all-year round, perhaps less often in September and October. It lays three to six bluish white eggs in a cup nest made of fine plant materials such as lichens, rootlets, and strips of bark, placed in a bush or at low or middle levels in a tree, around or higher off the ground. Egg incubation lasts 12-13 days, and the nestling period lasts 12-14 days.

The molt occurs in two different patterns which coincide with the blackness of the upperparts quite well. Here too is a broad zone of intergradation. Pacific birds molt after breeding, and females shed a few body feathers before breeding too. Juvenile males shed more remiges than females when molting into adult plumage. East of the 106th meridian west, birds molt strongly before breeding and replace another quantity of feathers afterwards, and post-juvenile molt does not differ significantly between the sexes. However, this seems dependent on the differing rainfall regimes; simply put, birds at least anywhere in the North American range molt most of their plumage at the end of the dry season and may replace more feathers at the end of the wet season.