Gould's Jewelfront

Appearance

"H.aurescens" ranges in size from 11 to 12 cm, with an average weight of about 6.2g. This is a sexually dimorphic species with minor differences in plumage and bill lengths between sexes. Both sexes have a narrow frontlet of glittering purplish-blue which is underdeveloped in immature individuals. The bill, black to dark coloured is “unspecialised” being relatively short and straight; while the irises are brown and tarsus black. The tail is forked with the central pair of feathers bronze-green while the other tail feathers have chestnut edges and bronze-green tips. Undertail coverts are a deep fawn colour and wings are purplish-brown. It is noted that there is some variation in plumage for this species, but these differences do not relate to location and is minimal when considering the wide range.

Specimens examined by Peter Cotton had an average wing length of 60.5mm and exposed culmen length of 18.5mm. Gould's original specimen had a bill of 2.5 cm and tail length of 31.75mm. The average c-value of the genome is 1.1135pg based on four specimens ranging from 1.045-1.162pg.

Males have shining grass green upperparts with the sides of the neck and lower throat glittering golden green bordered by a distinctive orange/rufous breast band. The chin, lores and upper throat are velvety black while the rest of the underparts are shining green. Females appear generally similar to the male but are somewhat duller coloured and have a green crown. They have a slightly larger bill than the male. The chin feathers have buff tips and the throat is greyish with green discs. Females also feature a malar stripe which is buff to chestnut coloured.

Naming

The common name commemorates the English ornithologist and bird artist John Gould.

Distribution

The exact distribution of "H.aurescens" is not known, but considered unusual since the other members of the genus have very narrow or restricted ranges, often at higher elevations in the Andes. It is widely distributed at elevations from 250m to 1150m and has been reported at elevations as high as 1450m. The northern boundary of the range is in southern Venezuela, which continues south through central Ecuador and Peru. The southern boundary is located in Bolivia. It occupies a large area of north-western Brazil where the eastern boundary of the range is found in the State of Para.

There have been several incidents of range expansion since the species was first described. Gould suggested the range was probably east of the Andes in Ecuador, Peru, and Brazil. The Venezuelan population was first encountered in 1941. At this time, the southern boundary was considered to be La Pampa in Peru but "H.aurescens" was detected in Bolivia in 1984 and in the Brazilian state of Mato Grosso in 2004. Otherwise the species is considered sedentary.

Status

"H.aurescens" is classified as Least Concern by the IUCN. There are suggestions the species is in decline but not at a rate which warrants classification as endangered. Numerous studies indicate the species is present but uncommon, with many long term studies only producing small numbers of observations A density of 1 individual per 100 hectares was determined in Peru when only one individual was observed in a 100Ha study site in a three-month survey.

Reproduction

Very little is known of the reproductive biology. Breeding is thought to occur between June and September with a clutch of two eggs incubated by the female. Two descriptions of female specimens indicate their gonads are well developed in February and April; but a single male specimen obtained in February had “small” gonads.

Food

Like most hummingbirds, "H.aurescens" is primarily nectarivous supplementing the diet with small arthropods hawked from the air. Little is known about the specific diet but they have been observed feeding on "Bromeliads" such as "Bromelia balansae" and "Costus" sp. in Brazil. 53% of specimens examined in 1986 had traces of arthropods in the gut. While typically a generalist understorey species, they have been observed feeding from flowers in tall trees; and visiting feeding stations in Ecuador, where they showed some aggression towards other birds in the area. An extensive study on feeding guilds in Brazilian hummingbirds indicated that "H.aurescens" was not generally territorial but they were omitted from the analysis of food plant use due to there being too few observations, with only three specimens netted in a two-year survey.