Tuesday, 28 March 2017
26-3-2017 RANCHO NATURALISTA - COLLARED ARACARI (Pteroglossus torquatus)
The collared aracari or collared araçari (Pteroglossus torquatus) is a near-passerine bird in the toucan family Ramphastidae. It is found from Mexico to Colombia and Venezuela.
The collared aracari inhabits the interior and edges of evergreen primary forest and mature secondary forest and also coffee, cacao, and fruit plantations. In the semi-arid parts of northern Colombia and Venezuela it also occurs in gallery forest. In elevation it is found from sea level to about 1,000 m (3,300 ft).
Like other toucans, the collared aracari is brightly marked and has a large bill. Adults are 38 to 41 cm (15 to 16 in) long and weigh 175 to 250 g (6.2 to 8.8 oz). Males and females have the same coloration of the bill and plumage but the female's bill is shorter than the male's. The three subspecies' bills are alike. The adult's bill has a narrow vertical white line at its base. Its maxilla is buffy white darkening to dull reddish brown at its base. Its tip and culmen are black. The maxilla has black and yellowish white notches. The bill's mandible is black. Adults of the nominate subspecies have mostly glossy black upperparts with a narrow cinnamon rufous collar at the base of the nape and bright red lower back, rump, and uppertail coverts. Their head, throat, and uppermost breast are greenish black. Their lower breast, belly, and undertail coverts are yellow. The breast has a variable red wash and a black spot in its center; the upper belly is crossed by a narrow red and black band. Their thighs are cinnamon to rufous. Juvenile collared aracaris are much duller than adults, with a sooty-black head and chest and brownish olive upperparts. The red rump and yellow underparts are paler, and the breast spot, belly band, and bill pattern are indistinct.
Subspecies P. t. erythrozonus is similar to the nominate but smaller and has a much smaller breast spot or none at all. P. t. nuchalis is also similar to the nominate, but its breast spot is usually larger and the white basal line on the bill is wider.
The most common call is described as "a high, sharp, squeaky, note, such as seek, pseek, pink or penk, or a two-parted pi-cheet or squi-zeek." They also make a "purr" and an "“aggressive, rasping grhhrr". A rattle call "bddddddt" may actually be non-vocal. Collared aracari's wings make an audible whir during flight.
Collared aracaris typically travel in groups of about six to 15 individuals that sometimes include other toucan species. They also roost communally; up to seven may occupy a cavity overnight.
The collared aracari's diet is mostly fruit but it also feeds on large insects, the eggs and nestlings of other birds, and other small vertebrates. It mostly forages from the forest's mid level to the canopy but will feed on fruits in the understory. They glean fruit by stretching from a perch, bending, and even hanging upside down. They regurgitate large fruit seeds which often remain viable.
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The collared aracari's breeding season is from January to May in most of its range. It nests in tree cavities, usually those excavated by large woodpeckers but also natural ones. They may enlarge the cavity, which can be up to 30 m (98 ft) above the ground. The clutch size is usually three eggs but can be as large as five. The incubation period is 16 to 17 days and both parents incubate. Fledging occurs 26 to 30 days after hatch. The parents and often up to three other adults provision the nestlings. They are fed mostly with insects when young.
The IUCN has assessed the collared aracari as being of Least Concern. It has an extremely large range but an unknown population size that is believed to be decreasing. No immediate threats have been identified. "Although it tolerates secondary forest, it nonetheless is very susceptible to deforestation" and is hunted by indigenous peoples.
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26-3-2017 RANCHO NATURALISTA - LESSON'S MOTMOT (Momotus lessonii)
Lesson's motmot (Momotus lessonii) or the blue-diademed motmot, is a colorful near-passerine bird found in forests and woodlands of southern Mexico to western Panama. This species and the blue-capped motmot, whooping motmot, Trinidad motmot, Amazonian motmot, and Andean motmot were all considered conspecific.
The central crown is black and surrounded by a blue band. There is a black eyemask. The call is a low owl-like ooo-doot.
These birds often sit still, and in their dense forest habitat can be difficult to see, despite their size. They eat small prey such as insects and lizards, and will also regularly take fruit.
Like most of the Coraciiformes, motmots nest in tunnels in banks, laying about three or four white eggs.
26-3-2017 RANCHO NATURALISTA - BLACK STRIPED SPARROW (Arremonops conirostris)
The black-striped sparrow (Arremonops conirostris) is a passerine bird found from eastern Honduras to western Ecuador, northern Brazil, and Venezuela.
It is a stocky sparrow with grey body, green back and black stripes on the head. Separated from other sparrows and finches by head pattern. Sexes alike. Found singly or in pairs in vines and thickets, usually at forest edges or in secondary forest shrubs. Listen for loud, sweet calls and quickening song.
The black-striped sparrow (Arremonops conirostris) is a passerine bird found from eastern Honduras to western Ecuador, northern Brazil, and Venezuela.
Stocky sparrow with grey body, green back and black stripes on head. Separated from other sparrows and finches by head pattern. Sexes alike. Found singly or in pairs in vines and thickets, usually at forest edges or in secondary forest shrubs. Listen for loud, sweet calls and quickening song.
This American sparrow is a common bird in humid lowlands and foothills up to 1,500 m (4,900 ft) altitude, in semiopen habitats such as thickets, young second growth, overgrown fields, shady plantations, and gardens.
The large, domed nest, built by the female, is made of coarse plant material and has a wide side entrance. It is normally placed less than 1 m (3.3 ft) up in dense growth, but may be as high as 1.8 m (5.9 ft). The clutch is two, rarely three, unmarked white eggs, which are incubated by the female alone for 12–14 days before hatching.
The black-striped sparrow is a mainly terrestrial species, 16.5 cm (6.5 in) long and weighing 37.5 g (1.32 oz). The adult is distinctive, with a grey head which has broad black stripes each side of the crown and narrower black stripes through each eye. The upperparts are olive, with yellow on the bend of the wing. The underparts are dull white shading to grey on the breast sides and to olive on the lower belly. Young birds have brown stripes on a yellower head, brownish-olive upperparts and yellow-olive underparts.
This species resembles the olive sparrow, but is larger, and the ranges do not overlap.
The black-striped sparrow feeds on insects, spiders, and seeds taken on the ground, and also picks berries and invertebrate prey from low bushes. It is seen in pairs, never in flocks, and is a shy and retiring species.
Habitats are Forest: Subtropical/Tropical Dry, Subtropical/Tropical Moist Lowland, Subtropical/Tropical Moist Montane; Shrubland: Subtropical/Tropical Moist; Artificial/Terrestrial: Plantations, Rural Gardens, Subtropical/Tropical Heavily Degraded Former Forest
27-3-2017 RANCHO NATURALISTA - WHITE IBIS (Eudocimus albus)
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The American white ibis (Eudocimus albus) is a species of long-legged wading bird that often flies in long loose lines or V formations. During the breeding season, American white ibises gather in huge colonies near water where males don’t hesitate to pirate food from unmated females and juveniles. Populations of this species in central Venezuela overlap and interbreed with the Scarlet ibis and the two have been even classified by some authorities as a single species.
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The white plumage and pink facial skin of adult American white ibises are distinctive. Adults have black wingtips that are usually only visible in flight. In non-breeding condition, the long downcurved bill and long legs are bright red-orange. During the first ten days of the breeding season, the skin darkens to a deep pink on the bill and an almost purple-tinted red on the legs. It then fades to a paler pink, and the tip of the bill becomes blackish. It is difficult to determine the sex of an adult American white ibis from its external appearance since the sexes have similar plumage. However, there is sexual dimorphism in size and proportion as males are significantly larger and heavier than females and have longer and stouter bills. This species is moderately large for an ibis but is relatively short legged, compact and bulky for a large wader. The newly hatched American white ibis is covered with violet down feathers, deepening to dark brown or black on the head and wings.
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The chest is often bare and there can be a white tuft on the head. The irises are brown. The exposed skin is pinkish initially, apart from the tip of the bill which is dark gray, but turns gray within a few days of hatching. The bill is short and straight at birth and has an egg tooth that falls off between days five and nine, and develops three black rings from around day six, before turning gray by around six weeks of age. The gray to sandy gray brown juvenile plumage appears between weeks two and six, and the face and bill become pink a few weeks later, while the legs remain gray. The irises have turned slate-gray by this stage. Once fledged, the juvenile American white ibis has largely brown plumage and only the rump, underwing, and underparts are white. The legs become light orange. As it matures, white feathers begin appearing on the back and it undergoes a gradual molt to obtain the white adult plumage. This is mostly complete by the end of the second year, although some brown feathers persist on the head and neck until the end of the third year. Juvenile birds take around two years to reach adult size and weight.
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American white ibises are gregarious birds, however, they are territorial and defend the nesting and display sites against intruders. When threatened or defending a territory American white ibises perform displays that include lunging forward with the bill in a horizontal posture, standing upright, and snapping the bill opposite another bird engaging in the same display. Birds also lunge and bite, often holding onto an opponent's head or wings. American white ibises are active during the day and for the most part, they forage for food by tactile probing. They wade slowly through shallow water and stick their long, downcurved bill into the substrate of the water body and sweep it back and forth across the bottom to pick out suitable food items. Groping with a wide open bill is a technique used by ibis in deeper water when alone, as is head swinging, in which the ibis swings its wide open bill widely in open water. On land, American white ibises locate prey by sight and pecks and do not have to insert their bill into the substrate. When not feeding they spend their time resting, roosting, attending to their nests, and flying. American white ibises fly with necks and legs outstretched, often in loose lines. These lines fly in an undulating pattern as they alternately flap and glide. Soaring in a circular pattern is also seen. Heights of 500 to 1,000 m (1,600 to 3,300 ft) may be reached as birds glide over flights of 20 km (12 mi) or more. More commonly, they fly between 60 and 100 m (200 and 330 ft) above the ground, gliding or flapping. When roosting these birds spend much time preening, biting, and working their feathers with their long bills, as well as rubbing the oil glands on the sides of their heads on back plumage. Before preening ibises often bathe; they squat in water 5-20 cm (2-7.9 in) deep and flick water over themselves with each wing in succession. Hundreds of birds may also bathe together around the time of courtship. The main call of American white ibises is a honking sound, transcribed as ‘urnk, urnk’, or ‘hunk, hunk’. This call is used in flight, courtship, or when disturbed. Birds also utter a muted ‘huu-huu-huu’ call while foraging, and make a squealing call in courtship. Young in the nest give a high-pitched ‘zziu’ as a begging call.
Monday, 27 March 2017
25-3-2017 RANCHO NATURALISTA, COSTA RICA - RUFOUS TAILED HUMMINGBIRD (Amazilia tzacatl)
The rufous-tailed hummingbird (Amazilia tzacatl ) is a medium-sized hummingbird in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is found from east-central Mexico through Central America and Colombia into Ecuador and Venezuela.
Like most hummingbirds, the rufous-tailed feeds on nectar and small insects. It is common at sugar water feeders and often seen in coffee and banana plantations. It is extremely territorial and aggressive at feeding sites such as flower patches and feeders, from which it chases other hummingbirds and large insects.
The rufous-tailed hummingbird is polygynous. Though it is aggressive while feeding, the species sometimes nests in loose colonies. Its breeding season varies widely across its range, but is within the February to November span. The female is entirely responsible for nest building, incubation of eggs, and care of nestlings. She lays two white eggs in a compact cup nest constructed from plant fibers, leaves, and spiderwebs covered with lichens and mosses. It is typically placed up to 6 m (20 ft) high on a thin horizontal twig. Incubation takes 15 to 19 days, and fledging another 18 to 22 days.
Sunday, 26 March 2017
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