Thursday, 30 May 2019

The Honduran Emerald (Amazilia luciae)


The Honduran Emerald (Amazilia luciae) is a little-known hummingbird in the family of Trochilidae. The bird is endemic to dry forest of Honduras. The bird natural habitats are subtropical or tropical dry forest and subtropical or tropical dry shrubland. Monroe the Birds of Honduras, summarized what was then known about the species and nothing has been added since. So far, eleven specimens have been collected at various localities from Santa Barbara in the west to Catacamas.

It is speculated that A. luciae was apparently a forest inhabitant and maybe common locally. Honduran Emerald is threatened by habitat loss and deforestation. The hummingbird restricted distribution in dry forest fragments and increasing human pressures on this habitat. The species was originally described in1867by George Lawrence.

In 1983, the AOU Check-list of North American Birds gives the habitat of A. luciae as Unidentified, localities usually in the humid lowlands. Though, plotting the collecting localities on a habitat map of Honduras reveals that all sites where A. luciae has been taken lie in or close to arid and mixed scrub and thorn forest. It is common inhabitant of arid thorn forest and scrubs in the upper Rio Aguan Valley Department of Yoro.

Like other hummingbirds it is a medium-sized hummingbird. It has a straight bill that is only slightly decurved. Normally the bill is blackish above and red below with a dark tip. The plumage pattern is simple, green upperparts that become more bronze toward the tale, blue throat, gray belly, forked tail that is bronzy green. Females are like males, but overall duller in coloration.

Approximately six kilometers west-northwest of Coyoles there were at least six emeralds found in one hour. As few flowers were evident, and all emeralds appeared in response to imitations of Ferruginous Pygmy-Owl calls. The Honduran Emerald seemed slow to respond and frequently appeared well after a mobbing band of other birds. This is mainly White-bellied Wrens and White-lored Gnatcatchers had formed. Emeralds normally perched 1.5 to 8 m up in bare trees and bushes and sat for up to 30 sets before losing interest.

There was a pygmy-owl did appear one emerald stayed with it for more than a few minutes. Moreover, the other bird species at the site included Cinnamon Hummingbird Black-headed Trogon, Elegant Trogon, Northern Beardless Tyrannulet, Brown-crested Flycatcher, and Green Jay.  At that site, emeralds were seen on the morning of 8 June 1988. At least 12 to 15 individuals Emerald were present in a small of area 200 x 200 m. However, at the second site, emeralds fed at numerous flowering plants.

Numerous birds also made prolonged insect-catching flights, mainly around the trunks of organ pipe cacti. One bird which was forty minutes strongly defended territory of about 10 x 10 m against the two other emeralds which infrequently came by to feed on Pithecelobium. Also, other bird’s characteristic of the Olanchito site included those listed for Coyoles, plus Thicket TinamouSpot-bellied Bobwhite, Striped Cuckoo, Lesser Ground-Cuckoo, Fork-tailed Emerald, and Arremonops sp., referred to Green-backed Sparrow by Monroe in1968.

At both sites, we found arid conditions like the upper Aguan valley. Therefore, most thorn forests had been cleared for grazing and what little remained was very dry and with few birds of any species apparent. From close-range observations of at least 15 emeralds, that A. luciae is slightly smaller than A. rutila and in posture and habits varies little from other Middle American Amazilia. Nevertheless, sexes appear to differ only slightly, mainly in the intensity and extent of the gorget. Honduran Emerald is considered solitary, like most hummingbirds. Individuals congregate in areas with a high density of nectar resources.

In life the maxilla is blackish, the mandible pinkish-red with a dark tip. The bill appears relatively long and slightly decurved. A white post-ocular spot and smaller pre- ocular spot lend the species a characteristic facial expression. The upperparts are deep emerald green and the upper tail-coverts and the tail is bronzer with a blackish sub terminal band on the outer rectrices.

Remiges are dark brown. Seen in the right light, the gorge flashes solidly turquoise but most of the time the underparts appear pale grayish, with dark mottling on the throat and upper chest. At rest, the wings fall slightly short of the distinctly cleft tail. Feet are dark gray. One bird (apparently singing) appeared in very fresh plumage.

A second, relatively dull female bird had the outer two primaries and several secondary’s very worn and faded in contrast to the newer and darker remiges; no rectrix molt was noted on any birds. The most commonly heard vocalizations were a hard, slightly metallic ticking call, often steadily repeated “chik, chik-chik, chik, chik. Also, a hard slightly buzzy chattering given in flight ‘zzchi’ and ‘chik chi zzhi’ reminiscent of the calls of Chestnut-collared Swift.

On returning to a perch, an emerald defending its feeding territory often uttered a dry, quiet gruff warbling, possibly the song, or at least a whisper song. During intra-specific chasing we heard a hard-buzzy chatter ‘chirr-rr-irr-rr-rr-rr-rr’ and a high sharp ‘siik’ given in pursuit. Moreover, an association with arid interior valleys explains the restricted range of A. luciae.

Hence, the given the pressures to convert much land to agricultural practices, A. luciae may be a threatened species. The actual distribution of the Honduran Emerald is still partly known. Within dry forests, the bird species has only ever been seen from interior valleys on the Caribbean Slope. An estimated population of 250 to 999 individuals is speculative, but the source is unknown.









No comments:

Post a Comment