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.
27-3-2017 VILLA LAPAS, COSTA RICA - TROPICAL KINGBIRD (Tyrannus melancholicus)
The tropical kingbird (Tyrannus melancholicus) is a large tyrant flycatcher. This bird breeds from southern Arizona and the lower Rio Grande Valley of Texas in the United States through Central America, South America as far as south as central Argentina and eastern Peru, and on Trinidad and Tobago. Birds from the northernmost and southern breeding areas migrate to warmer parts of the range after breeding.
An adult tropical kingbird is 22 cm (8.7 in) long, weighs 39 g (1.4 oz) and has a wingspan range of 38–41 cm. The head is pale gray, with a darker eye mask, an orange crown stripe, and a heavy gray bill. The back is grayish-green, and the wing and forked tail are brown. The throat is pale gray, becoming olive on the breast, with the rest of the underparts being yellow. The sexes are similar, but young birds have pale buff edges on the wing coverts.
27-3-2017 VILLA LAPAS, COSTA RICA - BARE THROATED TIGER HERON (Tigrisoma mexicanum)
The Bare-throated Tiger-Heron is a bird of tropical swamps. Along the coast, it is typically a mangrove species. It is found, however, in a variety of coastal and freshwater situations, typically characterized as forest edged aquatic habitats. It feeds in coastal lagoons, mangrove swamps, fresh water marshes, swamps, gallery forests along rivers and streams, and wet meadows. It feeds more in the open and in larger habitats than other tiger herons. It is primarily a coastal species occurring below 1,000 m. It avoids human habitats.
The primary foraging behavior of this cryptic heron is Standing in shallow water or on the edge of the water, with neck stretched out diagonally, waiting motionless for long periods. It also Walks slowly, often in situations away from cover. It is a solitary species, usually foraging alone. However a dozen have been seen in a loose group when food is readily available. It is primarily crepuscular but also partially nocturnal. When disturbed it takes flight and perches in a nearby tree. It eats fish, frogs, crabs, and flies.
Courtship is little understood in this species, and the displays reported have little context to them (Dickey and van Rossem 1938 Sutton et al. 1950, Wetmore 1965). The primary display appears to be a version of the Stretch—a pair faced each other, necks and bodies crouched horizontally, feathers fluffed up; the birds raise their bills and neck vertically, depressing the neck and body feathers, and emitting two or three hoarse booms or roars. They may sway the neck at the vertical. This may be repeated, and one bird may move toward the other. Mutual Bittern posture has also been described.
Eggs are dull white with a green tinge, rarely flecked with brown or buff. The usually unspotted eggs are not typical of the tiger herons (Dawn 1964). Two measured 56.6 x 43.5 mm and 58.1 x 45.3 mm. Clutches are 1-3 eggs. There is no information on incubation, chick development or fledging and little is known about the nesting success of this species. Nestlings are at risk to hawk (Buteogallus) predation (Lewis and Timm 1991).
The bare throat of this species was recognized for years as being highly distinctive. It is now placed in the same genus as the other two South American tiger herons. The tiger herons are a distinctive lineage of the Ardeidae, adapted to a forest existence. The five species constitute a sister group to all the other herons and bitterns and to the Boat Billed Heron (Sheldon et al. 1995).
The Bare-throated Tiger-Heron occurs in coastal Mexico, Central America, and northern South America.
Breeding range: In Mexico, it occurs as far north as south Tamaulipas and south Sonora, along both coasts, across the Isthmus of Tehuantepec, in all of the Yucatan, coastal in Central America through Panama, including Coida Island and Perles Archipelago but of limited distribution on the Caribbean slope, into extreme north west Colombia from Gulf of Urabá to the lower Atrato River valley.
Friday, 5 January 2018
Thursday, 4 January 2018
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