Sunday, 23 April 2017
Saturday, 22 April 2017
26-3-2017 RANCHO NATURALISTA, COSTA RICA - VARIEGATED SQUIRREL (Sciurus variegatoides)
The variegated squirrel (Sciurus variegatoides ) is a tree squirrel in the genus Sciurus found in Costa Rica, El Salvador, Guatemala, Honduras, southern Mexico, Nicaragua, and Panama. Fifteen subspecies are recognised. It is a common squirrel and the International Union for Conservation of Nature has rated it a "least-concern species". Variegated squirrels kept as pets in Germany have been implicated in the transmission of a bornavirus to humans from which three people have died.
Variegated squirrels are medium-sized tree squirrels. The are several subspecies recognised which differ in appearance. There is even often a considerable variation between the appearances of individuals in the same population. The dorsal colouration varies between dark brown to yellowish grey. The neck tends to be darker than other parts and there is often a paler patch behind the ears. The underparts are usually some shade of cinnamon. The tail is long and densely bushy; in Mexico it is black, sometimes with white tips to the hairs giving it a frosted appearance. In Nicaragua and Costa Rica, some individuals have pale underparts and tails.
Variegated squirrels are native to Central America. Their range extends from Mexico southwards through Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica and Panama. Habitats in which these squirrels occur include both dry deciduous forest and evergreen forest, secondary growth, and plantations.
Variegated squirrels are solitary and diurnal animals. They seldom descend to the ground and spend the night in a nest. Sometimes they build nests in a hole in a tree but more often construct them of leaves and build in the fork of a branch close to the trunk. These squirrels don't hibernate and spend most of their time in the trees. They are very agile and leap from one branch to another with ease. When threatened Variegated squirrels make chucking sounds and sometimes produce harsh chatter.
Variegated squirrels are herbivores (granivores, frugivores). They primarily are seed-eaters, but also consume fruits, some insects and nestlings. They try to avoid hard shelled seeds but do consume acorns.
Little information is known about the mating habits in Variegated squirrels. The breeding season occurs in April-May. Females build nests high up in the trees where they give birth to 2-8 kittens. The gestation period lasts around 33-46 days. Young are born blind and naked. Fur starts growing after 2 weeks and in 30-32 days kittens open their eyes. Young stay in the nest within 6 weeks and become weaned at 10 weeks after birth. They are independent after 15 weeks and reach reproductive maturity between 12 and 15 weeks of age.
26-3-2017 RANCHO NATURALISTA - RUFOUS TAILED HUMMINGBIRD (Amazilia tzacatl)
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.
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.
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.
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.
26-3-2017 RANCHO NATURALISTA - PASSERINI'S TANAGER (Ramphocelus passerinii)
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The scarlet-rumped tanager (Ramphocelus passerinii ) is a medium-sized passerine bird. This tanager is a resident breeder in the Caribbean lowlands from southern Mexico to western Panama. This species was formerly known as the scarlet-rumped tanager, but was renamed when the distinctive form found on the Pacific coast of Costa Rica and Panama was reclassified as a separate species, the Cherrie's tanager, Ramphocelus costaricensis. While most authorities have accepted this split, there are notable exceptions (e.g. the Howard and Moore checklist). It was renamed back to the scarlet-rumped tanager in 2018 when Cherrie's Tanager was lumped back into the species.
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This species was named for Carlo Passerini, a professor at the Museum of Zoology of the University of Florence.
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The adult Passerini's tanager is 16 cm long and weighs 31 g. The adult male is mainly black except for a scarlet rump, silvery bill and dark red iris. The female has a grey head, olive upperparts becoming brighter and paler on the rump, brownish wings and tail and ochre underparts. The female's plumage is the one that differs most from Cherrie's tanager. Immatures have an orange tint to the underparts and rump, and look like a paler and duller female Cherrie's tanager.
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The Passerini's tanager's call is a sharp wac. Its song consists of a few clear pleasant notes, delivered in shorter phrases than that of its Pacific relative.
It is very common from sea level to 1200 m altitude, and occurs occasionally up to 1700 m. The preferred habitat is semi-open areas including light second growth, woodland edges, gardens and pasture with bushes.
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Passerini's tanagers occur in pairs, small groups, or as part of a mixed-species feeding flock, and up to a dozen birds may roost together in dense thickets at night. This species feeds on certain small fruit, usually swallowed whole, insects and spiders.
The cup nest is built up to 6 m high in a tree. The normal clutch is two pale blue or grey eggs, marked with black, brown or lilac. This species will sometimes raise two broods in a season.
26-3-2017 RANCHO NATURALISTA - PALM TANAGER (Thraupis palmarum)
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The palm tanager (Thraupis palmarum ) is a medium-sized passerine bird. This tanager is a resident breeder from Nicaragua south to Bolivia, Paraguay and southern Brazil. It also breeds on Trinidad and, since 1962, on Tobago. In Trinidad and Tobago, it is known by colloquial names such as the "palmiste" on American Spanish countries (Colombian pronn: "pūlmist "), Brazil Pipira-verde (Portuguese pronn: "pəəpəərā-værd ") and the "green jean" in American English.
Adult palm tanagers are 19 cm (7.5 in) long and weigh 36 g (1.3 oz). They are grey to dull olive-green. The flight feathers are blackish, and the long tail is blackish edged with green. A yellow wingbar shows in flight. Sexes are similar, although females may be somewhat paler.
It occurs in semi-open areas including cultivation and gardens. The bulky cup nest is built in a tree, usually a palm, or under the eaves of a house, and the female incubates three, sometimes two, brown-blotched cream eggs for 14 days, with another 17 days to fledging.
Palm tanagers are social, restless but unwary birds which eat a wide variety of small fruit. They also regularly take some nectar and insects, including caterpillars. The song is fast and squeaky.
Thursday, 20 April 2017
26-3-2017 RANCHO NATURALISTA - CHESTNUT SIDED WARBLER (Setophaga pensylvanica)
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The chestnut-sided warbler (Setophaga pensylvanica ) is a New World warbler. They breed in eastern North America and in southern Canada westwards to the Canadian Prairies. They also breed in the Great Lakes region and in the eastern United States.
Countries
Antigua and Barbuda, Bahamas, Barbados, Cuba, Dominica, Dominican Republic, Guadeloupe, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago, Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Canada, United States, Ecuador, Colombia, Venezuela
This species is a moderately-sized New World warbler. Despite having very different plumage, it is thought to be closely related to the widespread yellow warbler.
In the summer, male chestnut-sided warblers are unmistakable in appearance. They display dark-streaked gray backs, white faces, black eyestripes and yellow crowns. Their underparts are white, with chestnut flanks, and they also have two white wing bars. The adult females resemble washed-out versions of the summer male, and in particular, the females lack the strong head pattern, and also have little to no chestnut coloring on their flanks.
26-3-2017 CATIE CENTER, COSTA RICA - TURKEY VULTURE (Cathartes aura)
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The turkey vulture, known scientifically as Cathartes aura, is a bird of prey that is the most widespread of the New World vultures. It is a large bird, with a wingspan of 160–183 cm (63–72 in), a length of 62–81 cm (24–32 in), and weight ranging from 0.8 to 2.41 kg (1.8 to 5.3 lb). The adult turkey vulture is recognized by its bald red head, dark plumage, and a relatively short, hooked, ivory-colored beak. The underwing coverts are silvery-gray, providing a contrast against the darker wing linings.
When observing the turkey vulture in flight, look for its distinctive silhouette with wings held in a shallow V-shape. The bird often rocks or tips from side to side, allowing the silvery-gray flight feathers to catch the light. The small, red head is proportionally small compared to its body, and the beak is short and hooked. The legs and feet are pinkish in color, often stained white due to urohidrosis, a cooling behavior where the bird defecates on its own legs.
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Turkey vultures inhabit a variety of open and semi-open areas, including subtropical forests, shrublands, pastures, and deserts. They are often found in areas that juxtapose with woodlands, which are important for nesting and roosting.
The turkey vulture's range extends from southern Canada to the southernmost tip of South America. It is a permanent resident in the southern United States, with northern populations migrating as far south as South America.
Turkey vultures are gregarious and roost in large community groups. They are known for their soaring flight, utilizing thermals to stay aloft with minimal flapping. On the ground, they have an ungainly, hopping walk and require significant effort to take flight. They are also known for their horaltic pose, where they spread their wings to dry, warm their body, or bake off bacteria.
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Lacking a syrinx, the turkey vulture's vocalizations are limited to grunts or low hisses.
Breeding season varies with latitude, starting in March in the southern United States and extending into August in northerly latitudes. Turkey vultures nest in protected locations such as cliffs, caves, or hollow trees, laying one to three cream-colored eggs with brown or lavender spots. Both parents incubate and care for the altricial chicks by regurgitating food.
The black vulture is similar in appearance but can be distinguished by its shorter tail and wings, which make it appear smaller in flight.
Turkey vultures feed almost exclusively on carrion, preferring recently dead animals and avoiding putrefied remains. They have a keen sense of smell and can detect the gases produced by decaying animals, which aids in locating food.
The turkey vulture is classified as Least Concern by the IUCN Red List. Populations appear stable, and it has not reached the threshold for inclusion as a threatened species.
26-3-2017 CATIE CENTER, COSTA RICA - PURPLE GALINULE (Porphyrio martinica)
The purple gallinule (Porphyrio martinicus) is a swamphen in the genus Porphyrio. It is in the order Gruiformes, meaning "crane-like", an order which also contains cranes, rails, and crakes. The purple gallinule is a rail species, placing it into the family Rallidae. It is also known locally as the yellow-legged gallinule. The specific name martinica denotes "of Martinique".
These birds are found in the southeastern states of the United States during the breeding season. They are resident species in southern Florida, the Gulf and Pacific coast of Mexico, parts of Central America, and the Caribbean. During the non-breeding season, they are found more inland in parts of Central America. They can also be found within South America during migration, and sometimes strays can be found as far north as Canada. The species' habitat is freshwater marsh with dense stands of vegetation.
The species has the greatest pattern of vagrancy amongst rails, with individuals recorded as far west as California and the Galápagos Islands, as far north as Iceland and Labrador, as far south as Tierra del Fuego, and as far east as Great Britain, Portugal and Cape Verde.
The courtship of purple gallinules occurs while they are standing and can be displayed by both sexes. Courtship occurs when the birds of a pair have been separated and then wander close to one another. They then perform the principal display, which is performed by both sexes at the same time. The display entails the bird standing in a slightly bent forward position, with the neck outstretched. The wings are held at an almost right angle to the body and bent at the wrist, so that the primaries are angled down. Following the principal display, one or both of the birds will strut and cut across the path of the other with half-lowered wings, or they will make a deep bow as they approach each other.
26-3-2017 CATIE CENTER, COSTA RICA - WESTERN CATTLE EGRET (Bubulcus ibis ssp. ibis)
The Cattle egret (Bubulcus ibis) is a cosmopolitan species of heron named for its association with cattle. It is the only member of the monotypic genus Bubulcus, although some authorities regard its two subspecies as full species, the Western cattle egret and the Eastern cattle egret. Despite the similarities in plumage to the egrets of the genus Egretta, it is more closely related to the herons of Ardea.
The Cattle egret is a stocky bird. It has a relatively short, thick neck, a sturdy bill, and a hunched posture. The nonbreeding adult has mainly white plumage, a yellow bill, and greyish-yellow legs. During the breeding season, adults of the nominate western subspecies develop orange-buff plumes on the back, breast, and crown, and the bill, legs, and irises become bright red for a brief period prior to pairing. The sexes are similar, but the male is marginally larger and has slightly longer breeding plumes than the female; juvenile birds lack coloured plumes and have a black bill.
Cattle egrets are native to parts of Asia, Africa, and Europe but they have undergone a rapid expansion in their distribution and successfully colonized much of the rest of the world in the last century. Many populations of Cattle egrets are highly migratory, while others are dispersive, and distinguishing between the two can be difficult. In many areas, populations can be both sedentary and migratory. In the Northern Hemisphere, migration is from cooler climes to warmer areas, but Cattle egrets nesting in Australia migrate to cooler Tasmania and New Zealand in the winter and return in the spring. Migration in western Africa is in response to rainfall, and in South America, migrating birds travel south of their breeding range in the non-breeding season. Populations in southern India appear to show local migrations in response to the monsoons. Cattle egrets inhabit wetlands, dry grassy habitats, semi-arid steppes, floodplains, freshwater swamps, shallow marshes, and mangroves. They are often found in fields, croplands, and pastures with poor drainage. When nesting, Cattle egrets are found in woodlands near lakes or rivers, in swamps, or on small inland or coastal islands.
26-3-2017 CATIE CENTER, COSTA RICA - GREAT TAILED GRACKLE (MALE) (Quiscalus mexicanus)
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The great-tailed grackle, or Mexican grackle (Quiscalus mexicanus), is a medium-sized, highly social passerine bird. Males are striking with iridescent black plumage and a purple-blue sheen on their head and upper body, while females are more subdued in brown with darker wings and tail. Both sexes boast long tails and bright yellow eyes, although juveniles have brown eyes and plumage similar to females, with streaks on the breast.
Adult males are unmistakable with their glossy black feathers and keel-shaped tails, which they can fold vertically. Females and juveniles can be identified by their brown coloration and long tails. The species is larger than starlings but smaller than crows, with a wingspan ranging from 18.9 to 22.8 inches.
Great-tailed grackles are found in a variety of clear areas for foraging, including pastures, wetlands, mangroves, and chaparral. They have adapted well to agricultural and urban environments.
Originally from the tropical lowlands of Central and South America, the great-tailed grackle has expanded its range significantly, now found from northwestern Venezuela and western Colombia to as far north as Minnesota, and from Oregon to Florida in the United States.
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These birds exhibit complex social behavior, with males displaying three distinct mating strategies: territorial, residential, and transient. They are known for their problem-solving abilities and behavioral flexibility.
Great-tailed grackles have a wide array of vocalizations, from sweet notes to harsh calls. Males have a more extensive repertoire, while females primarily engage in "chatter."
The breeding season begins in early to mid-April, with nests built near the tops of trees. Females lay 4 to 7 eggs, which are incubated for about 13 to 14 days. Young grackles fledge 12 to 17 days after hatching and are fed by parents for several weeks thereafter.
An opportunistic feeder, the great-tailed grackle's diet includes insects, larvae, lizards, nestlings, eggs, grains, fruits, and even small fish. They exhibit foraging behaviors such as turning over objects and wading into shallow waters to catch prey.
The great-tailed grackle is currently listed as Least Concern by the IUCN, indicating it is not at immediate risk of population decline or habitat loss.
26-3-2017 CATIE CENTER, COSTA RICA - BOAT BILLED HERON (Cochlearius cochlearius)
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The boat-billed heron grows to about 54 cm (21 in) long. Adults are pale grey to white in color, with chestnut-colored abdomens and black flanks. The massive, broad, scoop-like bill, which gives rise to this species' name, is mainly black. This bird is also adorned with a crest which is thought to be used in mate attraction as it is larger in males. The sexes are similar in appearance, the main differences being that females are slightly smaller, grayer in appearance, and have shorter crests than males. Newly hatched nestlings have green-yellow skin, with their upperparts covered in gray down feathers. Their upper bill is black and they have green-yellow legs. Juveniles are darker in color than adults and lack a crest.
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Boat-billed herons range from Mexico to Peru, Brazil, and northeastern Argentina. They are nonmigratory birds that tend to live in seasonal lagoons and estuaries, and nest in mangroves.
Boat-billed herons feed on shrimp and small fish such as Dormitator latifrons, a species of sleeper goby. They tend to forage in vegetative streams, shallow water, and lagoons. When foraging in streams, they use low-hanging branches and mangrove roots to stand over the water. In ponds they will walk slowly through the water up to 10 cm (4 in) deep or will forage near the water's edge. In order to capture prey they will lunge at fish or scoop the surface of the water with their bills which are uniquely shaped for this method of capture. Additionally, they have been observed using two different feeding techniques; standing and slowly stalking prey, or disturbing the water and chasing prey.Boat-billed herons will forage nocturnally, and have been seen leaving the roost 30 minutes after sundown to feed. It has been observed that they do not feed when a light source is present such as daylight, moonlight, or artificial light. One study hypothesized that in order to forage for food in the dark and in shallow, muddy water, their bills are sensitive to touch which helps them feel for their prey.
18-11-2016 MINHLA, MYANMAR - SLENDER SKIMMER DRAGONFLY (Orthetrum sabina)
Orthetrum sabina, the slender skimmer or green marsh hawk, is a species of dragonfly in the family Libellulidae. It is widespread, being found from south-eastern Europe and North Africa to Japan and south to Australia and Micronesia.
It is a medium-sized dragonfly with a wingspan of 60-85mm. Adults are greyish to greenish yellow with black and pale markings and green eyes. Its abdomen is greenish-yellow, marked with black.
It is very similar to Orthetrum serapia in appearance, with both species appearing in northern Australia. Pale markings on segment four of the abdomen do not extend into the posterior section when viewed from above on Orthetrum sabina. Females are similar to males in shape, colour and size; differing only in sexual characteristics. This dragonfly perches motionless on shrubs and dry twigs for long periods. It preys voraciously on smaller butterflies and dragonflies.
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