The Lesser Goldfinch (Carduelis psaltria), or Dark-backed Goldfinch, is a songbird of the Americas. Its range is from the southwestern United States (along the coast, as far north as southern Washington) to Venezuela and Peru. It migrates from the northern parts of its range. It utilizes most habitats almost any habitat with trees or shrubs except for dense forest. It is common and distinct in most areas, and will come near houses to feed at feeders in the southwest U.S. and almost anywhere else for thistle sock feeders.
The Lesser Goldfinch is 4 to 4.5 inches long and weighs only about 9.5 grams (0.3 ounces). It is the smallest North American Carduelis species. Southern species tend to be a bit larger and is more pronounced in the females. Males are easily recognized by their bright yellow underparts and big white patches in the tail and on the wings. They range from having solid black from the back to the upper head including the ear-coverts to having these regions medium green. Each of the back, crown and ear regions varies in darkness rather independently though as a rule the ears are not darker than the rest.
In most of its range, the Lesser Goldfinch is darker colored. Birds from far western U.S. and northern Mexico tend to be lighter in color. The zone in which both light and dark males occur on a regular basis is broadest in the north, and extends across the width of the Rocky Mountains and Sierra Madre Occidental ranges. It reaches the Pacific coast in southern Sonora to northern Sinaloa, roughly between area of Ciudad ObregÃ³n to CuliacÃ¡n. In the United States, the most diverse array of phenotypes can be found in Colorado and New Mexico. East of the 106th meridian west in southwestern Texas as well as in most of Mexico, almost all males have black backs.
The upperparts on females and young are more or less grayish olive-green, their underparts are yellowish, browner in immatures. They have only a narrow strip of white on the wings (with other white markings in some forms) and little or no white on the tail. They are best distinguished from other members of the genus by the combination of small size, upperparts without white or yellow, and dark gray bill. In all plumages this bird can easily be taken for a New World warbler if the typical finch bill isn’t seen well.
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/October. It lays three or four 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. Molting occurs differently depending on the bird’s range. Pacific birds molt after breeding while birds east of the 106th meridian west molt before breeding. However, it is more reliable to believe that this species, anywhere within its range, molt at the end of the dry season and may replace more feathers at the end of the wet season as well.