Betula utilis to overuse of the tree for firewood. "Betula utilis" was described and named by botanist David Don in his "Prodromus Florae Nepalensis" (1825), from specimens collected by Nathaniel Wallich in Nepal in 1820. "Betula jacquemontii" (Spach), first described and named in 1841, was later found to be a variety of "B. utilis", and is now "Betula utilis" var. "jacquemontii". In its native habitat, "B. utilis" tends to form forests, growing as a shrub or tree reaching up to tall. It frequently grows among scattered conifers, with an undergrowth of shrubs that typically includes evergreen "Rhododendron". The tree depends on moisture
White-winged swallow White-winged swallow The white-winged swallow ("Tachycineta albiventer") is a resident breeding swallow in tropical South America from Colombia, Venezuela, and Trinidad south to northern Argentina. It is not found west of the Andes. This swallow is largely non-migratory. The genus "Tachycineta" was established for this group of swallows by German ornithologist Jean Cabanis in 1850. The genus name derives from Ancient Greek "takhukinetos", "moving quickly"; the specific name "albiventer" is from Latin "albus", "white", and "venter", "belly". This swallow is monotypic, and no subspecies are currently recognized. The adult white-winged swallow is long and weighs . It has iridescent blue-green