Identification: White-tufted Sunbeam (Aglaeactis castelnaudii) species is a typical sunbeam with a stocky outline, short bill, and mainly dark blackish-brown plumage, with a broad, glistening purple rump patch (a little less vivid in females). This species is in the family of Trochilidae. It is named for the scattered teardrop-shaped white feathers on its breast. Subsp. regalis is lighter than the nominate and also has a chestnut rather than a blackish-brown tail.
A territorial bird is often seen watching over its patch from a high perch, but it is subordinate to the Shining Sunbeam and keeps lowering levels where the two species occur together. It clings to flowers to feed and gracefully pursues insects on the wing.
It may undertake short seasonal movements to lower elevations but can tolerate brief spells of severe weather. Furthermore, it has a restricted distribution only in Peru and is thought to be declining, but it has the advantage of occurring in protected areas, notably the famous Machu Picchu which is UNESCO World Heritage Site.
Distribution: Subsp. castelnaudii occurs in the Andes of south-central Peru; subsp. regalis occurs in the Andes of central Peru.
Habitat: This hummingbird habitat is subtropical and tropical patchy montane forest and forest edges; normally high altitude of 11,500–15,100 ft. (3,500–4,600 m). This hummingbird can often be seen perching perilously at the very top of trees; except for where their array overlaps with Shining Sunbeams (Aglaeactis cupripennis). Moreover, hummingbirds have frequently hidden away on lower branches and within thick vegetation.
Size: The average adult size is 43⁄8–43⁄4 in (11–12 cm) with a weight around 7–8.5 grams.
Call, Song, Sounds: The call of White-tufted Sunbeam is a soft and inconspicuous sound. The song is repeated tzzit call and, during chases, a twittering series of titi-tsreeet-tsreeet-tsreeet sounds, it can also emit a thin, high-pitched seeeeuuuu noise.
Diet: The white-tufted sunbeam diet consists of catching insects in midair and nectar from flowering plants, i.e., Berberis, Labiatae, and Lupinus.
Status: This hummingbird is near threatened according to the criterion of the IUCN Red List, has a declining population and has a fragmented range.
