Friday, 28 April 2017
24-3-2017 RANCHO NATURALISTA, COSTA RICA - CHESTNUT HEADED OROPENDOLA (Psarocolius wagleri)
The chestnut-headed oropendola (Psarocolius wagleri) is a New World tropical icterid bird. The scientific name of the species commemorates Johann Georg Wagler, who established Psarocolius, the oropendola genus.
The male is 35 cm (14 in) long and weighs 225 g (7.9 oz); the smaller female is 28 cm (11 in) long and weighs 125 g (4.4 oz). The wings are very long. Adult males are mainly black with a chestnut head and rump and a tail which is bright yellow apart from two dark central feathers. The iris is blue and the long bill is whitish. Females are similar, but smaller and duller than males. Young birds are duller than adults and have brown eyes. The populations south of an area around the border of Honduras and Nicaragua are sometimes separated as a subspecies P. w. ridgwayi, but the separation of this form has been questioned.
The distinctive songs of the male include a gurgle followed by a crash guu-guu-PHRRRRTTT. Both sexes have loud chek and chuk calls.
It is a resident breeder in the Caribbean coastal lowlands from southern Mexico to central Costa Rica, both slopes of southern Costa Rica and Panama, and the Pacific lowlands of Colombia and north-eastern Ecuador. Though it usually stays below 1,000 m (3,300 ft) ASL, it has also been recorded as much as 1,300 m (4,300 ft) ASL, for example in the Serranía de las Quinchas of Colombia. It may in be more common at such high altitudes at particular times or in particular places, but its altitudinal movements are insufficiently understood.[2] The species is common across its large range and is not considered threatened by the IUCN.[1]
The chestnut-headed oropendola inhabits forest canopy, edges and old plantations. It is a quite common bird in parts of its range, seen in small flocks foraging in trees for large insects, fruit and berries.
It is a colonial breeder which builds a hanging woven nest of fibres and vines, 60–100 cm (24–39 in) long, high in a tree. There may be 40–50 females and only 4–5 males in a colony. The female lays two dark-marked pale blue eggs which hatch in 17 days and fledge in 30. Botflies (Oestridae) are the main cause of nestling mortality, but brood parasitism by giant cowbirds (Molothrus oryzivorus) also occurs, and the young cowbirds will feed on the fly larvae.
Thursday, 27 April 2017
24-3-2017 RANCHO NATURALISTA, COSTA RICA - BROWN JAY (Psilorhinus morio)
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The brown jay (Psilorhinus morio ) is a large American jay which has the habitus of a magpie, but is slightly smaller and with a shorter tail, though the bill is larger.
It occurs from Mexico south into Central America on the Gulf slope. The northernmost extent of the bird is in the Rio Grande Valley of Texas.
Brown jays vary in plumage geographically: there are two main groups. Northern birds are almost completely dark brown, with lighter brown on the underparts. Southern birds are white-bellied and have bright white tips to the outer tail feathers. The intergrade zone is in Veracruz, Mexico.
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Adults in both populations have black bills, legs, and feet. Immatures have yellow bare parts, including yellow eye-rings.
The voice is a loud but low-pitched pee-ah call and is often modified to suit its situation or mood.
In Central America, the brown jay is not found in El Salvador; the range is on the Pacific side of Central America in Nicaragua, Costa Rica, and western Panama. It does not extend into South America.
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Food is sought largely in trees but brown jays also take some food from the ground. They are rather indiscriminate feeders. Insects and a wide range of other invertebrates are taken, also lizards, nectar, and fruit (e.g. that of Trophis racemosa (Moraceae)). Though they will take eggs and nestlings, they appear not to if there is plenty of other food available.
The nest is built in a tree or large shrub with both sexes helping in construction. There are normally three eggs laid but six is not unusual. Incubation is between 18 and 20 days. Only the female broods but the male feeds her while doing so.
Sometimes the offspring from a previous season will help in raising the chicks. If a helper bird returns with food, it will give it to one of the resident parents to feed the chicks.
24-3-2017 RANCHO NATURALISTA, COSTA RICA - BLUE GREY TANAGER (Thraupis episcopus)
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The blue-gray tanager (Thraupis episcopus ) is a medium-sized South American songbird of the tanager family, Thraupidae. Its range is from Mexico south to northeast Bolivia and northern Brazil, all of the Amazon Basin, except the very south. It has been introduced to Lima (Peru). On Trinidad and Tobago, this bird is called blue jean.
The blue-gray tanager is 16–18 cm (6.3–7.1 in) long and weighs 30–40 g (1.1–1.4 oz). Adults have a light bluish head and underparts, with darker blue upperparts and a shoulder patch colored a different hue of blue. The bill is short and quite thick. Sexes are similar, but the immature is much duller in plumage.
The song is a squeaky twittering, interspersed with tseee and tsuup call notes.
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The breeding habitat is open woodland, cultivated areas and gardens. The blue-gray tanager lives mainly on fruit, but will also take some nectar and insects. This is a common, restless, noisy and confiding species, usually found in pairs, but sometimes small groups. It thrives around human habitation, and will take some cultivated fruit like papayas (Carica papaya ).
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One to three, usually two, dark-marked whitish to gray-green eggs are laid in a deep cup nest in a high tree fork or building crevice. Incubation by the female is 14 days with another 17 to fledging. The nest is sometimes parasitised by Molothrus cowbirds.
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Two birds studied in the Parque Nacional de La Macarena of Colombia were infected with microfilariae, an undetermined Trypanosoma species, and another blood parasite that could not be identified. Two other birds, examined near Turbo (also in Colombia), did not have blood parasites.
Widespread and common throughout its large range, the blue-gray tanager is evaluated as Least Concern on the IUCN Red List of Threatened Species.
25-3-2017 RANCHO NATURALISTA, COSTA RICA - TOGARNA HAIRSTREAK BUTTERFLY (Arawacus togarna)
This buttefly has very distinctive stripes. It is interesting that this butterfly has a "false head". In the photo, the head of the butterfly is actually on the right. The hairstreak's hindwing tails look mlike antennae and the black extension on the hindwings looks like a head. Probably a defense against some visual predators that may target the head.
The habitat of this butterfly are openings in Pacific lowland forest.
25-3-2017 RANCHO NATURALISTA, COSTA RICA - SUMMER TANAGER (FEMALE) (Piranga rubra)
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The Summer Tanager (Piranga rubra) is a medium-sized songbird of vibrant plumage, belonging to the cardinal family (Cardinalidae). Adult males are resplendent in rose red, while females don a more subdued palette of orangish underparts and olive upperparts, with olive-brown wings and tail.
To identify the Summer Tanager, look for the stout pointed bill and the striking sexual dimorphism in coloration. Males are entirely rose red, a hue not found in many other birds. Females, on the other hand, are more camouflaged with their olive and orange tones. The species measures approximately 17 cm in length, with a wingspan ranging from 28 to 30 cm.
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These tanagers favor open wooded areas, particularly those with a generous sprinkling of oak trees. They thrive in the southern reaches of the United States, where the canopy provides both shelter and sustenance.
During the breeding season, the Summer Tanager can be found across the southern United States, extending as far north as Iowa. Come winter, they migrate to the warmer climes of Mexico, Central America, and northern South America. They are considered extremely rare visitors to western Europe.
The Summer Tanager is often a hidden gem, foraging high in the treetops and occasionally darting out to snatch insects in mid-flight. They exhibit a preference for bees and wasps, deftly plucking them from the air with remarkable agility.
The male's song is reminiscent of the American Robin, a series of melodic units delivered in a steady stream. However, the Summer Tanager's song is more monotonous, sometimes comprising just a few units. It is clearer and less nasal than the Scarlet Tanager's. Their call is a sharp, agitated-sounding "pi-tuk" or "pik-i-tuk-i-tuk."
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Summer Tanagers construct a cup-shaped nest on a horizontal tree branch, where they lay their eggs and raise their young in the seclusion of the leafy canopy.
The Summer Tanager can be confused with the Hepatic Tanager, but the latter can be distinguished by its darker bill.
These birds primarily consume insects, with a particular fondness for bees and wasps. They also partake in berries and are known to enjoy the fruit of the Cymbopetalum mayanum tree during their winter stay in the tropics. They are amenable to visiting bird feeders in residential areas.
The IUCN Red List classifies the Summer Tanager as Least Concern, indicating a stable population without immediate threats to its survival.
25-3-2017 RANCHO NATURALISTA, COSTA RICA - LEAST FLYCATCHER (Empidonax minimus)
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The least flycatcher (Empidonax minimus ) (also called chebec, or chebecker, after the sound it makes) is a small insect-eating bird. It is the smallest Empidonax flycatcher in eastern North America.
The least flycatcher is hard to distinguish from the other birds of its genus. The bird is one of the smallest of the genus Empidonax, measuring 12 to 14 cm in height with a wingspan of 19 to 22 cm and weighing approximately 10.3 g. Its plumage is dull olive-gray on its back and whitish on its belly, notably brighter than the other Empidonax birds. The least flycatcher's wings are lined with two white bars, and white rings contour its eyes. Its beak is short and the lower mandible is yellowish. The juveniles look similar to the adults except that their wing bars are slightly darker, with tawny/olive hues. Because other flycatchers also have those field marks, the best way to identify the least flycatcher is by its call and habitat.
The least flycatcher inhabits the Eastern Rockies of Canada, and the Central-North and Northeastern United-States. During winter, they migrate to Central America and establish themselves from Mexico to Panama.
25-3-2017 RANCHO NATURALISTA, COSTA RICA - BROWN JAY (Psilorhinus morio)
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The brown jay (Psilorhinus morio ) is a large American jay which has the habitus of a magpie, but is slightly smaller and with a shorter tail, though the bill is larger.
It occurs from Mexico south into Central America on the Gulf slope. The northernmost extent of the bird is in the Rio Grande Valley of Texas.
Brown jays vary in plumage geographically: there are two main groups. Northern birds are almost completely dark brown, with lighter brown on the underparts. Southern birds are white-bellied and have bright white tips to the outer tail feathers. The intergrade zone is in Veracruz, Mexico.
Adults in both populations have black bills, legs, and feet. Immatures have yellow bare parts, including yellow eye-rings.
The voice is a loud but low-pitched pee-ah call and is often modified to suit its situation or mood.
Food is sought largely in trees but brown jays also take some food from the ground. They are rather indiscriminate feeders. Insects and a wide range of other invertebrates are taken, also lizards, nectar, and fruit (e.g. that of Trophis racemosa (Moraceae)). Though they will take eggs and nestlings, they appear not to if there is plenty of other food available.
The nest is built in a tree or large shrub with both sexes helping in construction. There are normally three eggs laid but six is not unusual. Incubation is between 18 and 20 days. Only the female broods but the male feeds her while doing so.
Sometimes the offspring from a previous season will help in raising the chicks. If a helper bird returns with food, it will give it to one of the resident parents to feed the chicks.
25-3-2017 TUIS CARTAGO, COSTA RICA - GREEN HERON (Butorides virescens)
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The Green heron (Butorides virescens) is a small secretive heron that lives along shaded riverbanks or quiet streams in areas of dense vegetation. It is often somewhat secretive but is sometimes to be seen crying "kyow" while flying up a creek. When in the open, it will often flick its short tail nervously, while raising and lowering its crest. The Green heron was long considered conspecific with its sister species the Striated heron (Butorides striata), and together they were called "Green-backed heron".
The neck of the Green heron is often pulled in tight against the body. Adults have a glossy, greenish-black cap, a greenish back and wings that are grey-black grading into green or blue, a chestnut neck with a white line down the front, grey underparts, and short yellow legs. The bill is dark with a long, sharp point. Female adults tend to be smaller than males, and have duller and lighter plumage, particularly in the breeding season. Juveniles are duller, with the head sides, neck, and underparts streaked brown and white, tan-splotched back and wing coverts, and greenish-yellow legs and bill. Hatchlings are covered in down feathers, light grey above, and white on the belly.
25-3-2017 RANCHO NATURALISTA, COSTA RICA - Elaenia flavogaster)
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The yellow-bellied elaenia (Elaenia flavogaster) is a small bird of the tyrant flycatcher family. It breeds from southern Mexico and the Yucatán Peninsula through Central and South America as far as northern Argentina, and on Trinidad and Tobago.
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