Regulidae

A kinglet is a small bird in the family Regulidae, previously classified with Old World warblers. The name “Regulidae” comes from the Latin word for “petty king,” referring to the colorful crowns of adult birds. This family includes six species found in North America and Eurasia, with the Madeira firecrest recently classified as a separate species. Notably, the ruby-crowned kinglet has enough differences to be placed in its own genus, Corthylio.

Kinglets are among the smallest passerines, measuring 8 to 11 cm and weighing 6–8 g, with the sexes being similar in size. They have medium-length wings, small bills, and distinctive head markings, with males sporting colorful crown patches. Kinglets are typically found in conifer forests across the Nearctic and Palearctic realms, though some species adapt to other habitats during migration.

Due to their tiny size and high metabolism, kinglets must constantly forage, primarily eating insects like aphids and springtails. Their nests are small, spherical cups made of moss, lichen, and spiderwebs, usually built high in conifers. A female lays 7 to 12 eggs, which incubate for 15 to 17 days, and the nestlings stay for 19 to 24 days before fledging. Kinglets have high fecundity but also high mortality rates, with adult survival for the goldcrest estimated at over 80% annually and a maximum lifespan of about six years.