Monday, 8 January 2018
Sunday, 7 January 2018
28-3-2017 CARARA NAT PARK, COSTA RICA - NORTHERN GHOST BAT (Diclidurus albus)
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The northern ghost bat can be distinguished from other members of its genus by the presence of a vestigial thumb with a near-absent claw. Amongst the northern ghost bat population, sexual dimorphism is present. Specifically, males tend to be slightly larger in size when compared to females. Diclidurus albus is intermediate in weight relative to other members of the family Emballonuridae.
The northern ghost bat has a widely shaped clavicle bone, with large areas of attachment for the pectoralis muscle. It also has a large glandular structure on its uropatagium. The functional significance of this glandular structure is thought to be analogous to that of wing sacs in other emballonurids. When breeding, the wing sacs of other emballonurids become enlarged to attract females.
The penis of the northern ghost bat does not employ a baculum, but rather, is composed of four cartilaginous bodies. It is about 5.5 mm long and 3.1 mm in diameter. The glans penis is white in color, and the prepuce is encased in a layer of short, fine hair. The testes are spindle-like in shape, symmetrical, and enclosed in a black tunica. In females, the ovaries are ovoid in shape and are roughly 2.8 mm long and 0.8 mm in diameter.
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29-3-2017 HOTEL BOUGANVILLEA, COSTA RICA - RUFOUS TAILED HUMMINGBIRD (Amazilia tzacatl)
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The rufous-tailed hummingbird, Amazilia tzacatl, is a medium-sized member of the hummingbird family, Trochilidae, known for its distinctive chestnut-brown tail. This avian jewel measures between 9 to 11 cm in length and weighs around 5 grams, with males and females exhibiting slight variations in plumage.
Adult males of the nominate subspecies boast a green crown and upperparts, save for the chestnut-brown lores and uppertail coverts. The tail is predominantly chestnut-brown with bronze-green tips. The throat and upper breast shimmer with green, and the lower breast transitions to gray, leading to a white belly and chestnut-brown undertail coverts. Females have a paler gray lower breast and more pronounced scalloping on the throat. Juveniles display a cinnamon wash on the lower breast and sides, with cinnamon-tipped lower back and rump feathers. The bill is a striking combination of black and red, with the outer half of the maxilla black and the inner half red, while the mandible is red with a black tip.
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This species thrives in open landscapes such as clearings, gardens, and forest edges, as well as in low, brushy secondary forests. It is also a frequent visitor to feeders.
The rufous-tailed hummingbird is found from east-central Mexico through Central America and Colombia, extending into Ecuador and Venezuela. It occupies a range of elevations from sea level up to 2,500 meters in Ecuador, though such high altitudes may be seasonal or local.
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Renowned for its territorial nature, the rufous-tailed hummingbird is a fierce defender of feeding territories, including flower patches and feeders, where it will chase away other hummingbirds and large insects.
The species' vocalizations include a high, thin, and squeaky song composed of chirps and tsi sounds, as well as hard, smacking calls and dry chips that can merge into a rattling sound.
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The rufous-tailed hummingbird is polygynous and may nest in loose colonies. The female single-handedly constructs a cup nest from plant fibers, leaves, and spiderwebs, adorned with lichens and mosses. She lays two white eggs, which she incubates for 15 to 19 days, with fledglings leaving the nest after another 18 to 22 days.
While there are several subspecies of the rufous-tailed hummingbird, they can be distinguished by size, bill shape, and coloration details. For example, A. t. handleyi is larger and darker, while A. t. fuscicaudata is smaller with a shorter bill.
The diet consists primarily of nectar and small insects. This hummingbird is a common sight in coffee and banana plantations and is known to frequent sugar water feeders.
The IUCN has classified the rufous-tailed hummingbird as Least Concern, with an estimated population of over five million mature individuals. The species may even benefit from certain human activities that create open spaces suitable for its habitat.
Saturday, 6 January 2018
29-3-2017 HOTEL BOUGANVILLEA, COSTA RICA - GROOVE BILLED ANI (Crotophaga sulcirostris)
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The groove-billed ani (Crotophaga sulcirostris ) is a tropical bird in the cuckoo family with a long tail and a large, curved beak. It is a resident species throughout most of its range, from southern Texas, central Mexico and The Bahamas, through Central America, to northern Colombia and Venezuela, and coastal Ecuador and Peru. It only retreats from the northern limits of its range in Texas and northern Mexico during winter.
The groove-billed ani is about 34 cm (13 in) long, and weighs 70–90 g (2.5–3.2 oz). Wingspan ranges from 41-46 cm (16-18 in). It is completely black, with a very long tail almost as long as its body. It has a huge bill with lengthwise grooves running the length of the upper mandible. It is very similar to the smooth-billed ani, some specimens of which have bills as small as the groove-billed and with grooves on the basal half. The two species are best distinguished by voice and range. In flight, the ani alternates between quick, choppy flaps and short glides.
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Like other anis, the groove-billed is found in open and partly open country, such as pastures, savanna, and orchards. It feeds largely on a mixed diet of insects, seeds, and fruits.
The groove-billed ani lives in small groups of one to five breeding pairs. They defend a single territory and lay their eggs in one communal nest. All group members incubate the eggs and care for the young.
The groove-billed ani is protected under the Migratory Bird Treaty Act of 1918.
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