White-tufted sunbeam

An adult white-tufted sunbeam is approximately 12 cm in height and weighs 7- 8.5 g. The bill is straight and black and there is a notable patch of white feathers directly under the chin on the breast. The rest of the body is described as tawny and darkly-colored. There are iridescent feathers on the back of the bird that are most noticeable in flight and while hovering. Males and females of the species exhibit subtle sexual dimorphism.^[3]

Males are fuscous-black on their upper backs with a magenta reflection on their rump and lower back. Their tails are forked. The belly, side, and neck of a male are dull brown. The throat and pectoral band are blackish in color. True to their name, there is a white feather tuft on the central breast. Females are very similar to males, but have a less iridescent back and a smaller tail fork.^[3]

Juvenile white-tufted sunbeams have a more uniform, brown exterior with no iridescent feathers.^[3]

The white-tufted sunbeam has a small and fragmented range, estimated at a maximum of 832 km² (approximately 321 sq mi), cumulatively. This number was calculated using the remaining tree area in their range.^[4] The species has been observed to have a range that is not restricted to a specific number of locations (i.e. the range is fragmented). These hummingbirds reside in two main areas located in Central and Southern-Central Peru. They prefer drier parts of evergreen montane forests, intermontane valleys, and open shrub.^[5] White-tufted sunbeams can often be seen perching precariously at the very top of trees; except for where their range overlaps with Shining Sunbeams (Aglaeactis cupripennis). In these areas, they are often hidden away on lower branches and within dense vegetation.^[6]

Like many hummingbirds, the white-tufted sunbeam has a very soft and inconspicuous call. Vocalizations include a repeated tzit call and, during chases, a twittering series of titi-tsreet-tsreet-tsreet sounds. The latter is used during hostile situations only. The white-tufted sunbeam can also emit a thin, high-pitched seeeuuu noise.^[3]

Staples of this hummingbird's diet include flower nectar and insects. Some of the flowering plants utilized by this species include members of the following genera:

• Barnadesia
• Berberis
• Brachyotum
• Centropogon
• Labiatae
• Lupinus
• Salpichroa
• Siphocamplos

The white-tufted sunbeam is known for always clinging to flowers while it feeds and for catching insects in midair.^[3]

This hummingbird's divided range meets the criterion of the IUCN (International Union for Conservation) Red List, and is therefore evaluated as near threatened. Despite a general agreement among researchers that this species has a declining population and fragmented range, it is not defined as vulnerable by the IUCN because the range is not considered severely fragmented.^[1]

While the hummingbird's exact population size is unknown, white-tufted sunbeams have been described as “common but patchily distributed."^[7] The suspected cause of population decline is ongoing habitat loss due to deforestation.^[1]