Monday 17 April 2017
28-3-2017 VILLA LAPAS, COSTA RICA - GREEN KINGFISHER (Chloroceryle americana)
The green kingfisher (Chloroceryle americana) is a species of "water kingfisher" in the subfamily Cerylinae of the family Alcedinidae. It is found from southern Texas in the United States south through Central America, in every mainland South American country except Chile and Trinidad and Tobago.
The green kingfisher inhabits wooded shorelines of streams and freshwater ponds and lakes. It favors still or slow-moving water, and though it requires low vegetation for hunting perches it generally prefers relatively open habitat rather than dense forest. It is a year-round resident throughout its range but roams a territory that may be as much as 1 km (0.6 mi) or more of river.
The Green kingfisher usually hunts from a perch from which it dives into water for its prey. The perch is typically about 1 to 1.5 m (3 to 5 ft) high; it may be directly over water or within a few meters of its edge. In a study in Amazonia about half of the perches were bare snags and the rest were a mix of leafless and leafy trees and bushes. It usually shifts perches after each foray. Occasionally it hovers before diving, sometimes from as high as 6 m (20 ft). Pairs often defend feeding territories from other green kingfishers but seldom from other kingfisher species.
The prey is mostly small fish but includes crustaceans such as shrimp and also adult and nymph aquatic and terrestrial insects. The size of the fish taken varies, apparently with availability and the presence of other species of kingfishers. Studies have published sizes as 8 to 80 mm (0.31 to 3.1 in), as averages of 19.4 mm (0.76 in) and 41.1 mm (1.6 in) at different sites, and as "seldom exceeding a length of two inches".
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The green kingfisher's breeding season varies geographically. In Central America it is during the dry season of spring and early summer. In Suriname and Guyana, it usually extends to August and occasionally to December or beyond. Breeding dates further south have not been documented. Both members of a pair excavate a nest burrow, almost always in an earthen bank of a stream or river. It is up to 1 m (3 ft) long with a small nest chamber at the end. The clutch size varies from two to six. The incubation period is 19 to 21 days; usually the female incubates at night and the parents alternate during the day. The young fledge 26 to 27 days after hatching and the parents chase juveniles from their territory about 29 days after fledging.
24-3-2017 RANCHO NATURALISTA, COSTA RICA - WHITE NECKED JACOBIN (Florisuga mellivora) COURTESY MRS VALERIE FISHER
The white-necked jacobin (Florisuga mellivora) is a medium-size hummingbird that ranges from Mexico south through Central America and northern South America into Brazil, Peru and Bolivia. It is also found in Trinidad & Tobago.
Other common names are great jacobin and collared hummingbird.
The nominate subspecies of white-necked jacobin, F. m. mellivora, is found from southern Veracruz and northern Oaxaca, Mexico, through southern Belize, northern Guatemala, eastern Honduras and Nicaragua, eastern and western Costa Rica, and Panama into South America. In that continent it is found in much of Colombia and Ecuador, eastern Peru, northern Bolivia, most of Venezuela, the Guianas, the northwestern half of Brazil, and the island of Trinidad. F. m. flabellifera is found only on the island of Tobago. The nominate has been recorded as a vagrant in Argentina and on the islands of Aruba and Curaçao.
The white-necked jacobin inhabits the canopy and edges of humid forest and also semi-open landscapes such as tall secondary forest, gallery forest, and coffee and cacao plantations. It is usually seen high in trees but comes lower at edges and in clearings. In elevation it usually ranges from sea level to about 900 m (3,000 ft) but has also rarely been seen as high as 1,500 m (4,900 ft).
The white-necked jacobin breeds in the dry to early wet seasons, which vary across their range. The nest is a shallow cup of plant down and cobweb placed on the upper surface of a leaf where another leaf provides a "roof". It is typically 1 to 3 m (3 to 10 ft) above ground and sometimes near a stream. Males display and chase in the canopy and along edges during the breeding season. Females use a fluttering flight to distract predators.
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23-3-2017 TROGON LODGE, COSTA RICA - ACORN WOODPECKER (Melanerpes formicivorus) COURTESY MRS VALERIE FISHER
The acorn woodpecker (Melanerpes formicivorus) is a medium-sized woodpecker, 21 cm (8.3 in) long, with an average weight of 85 g (3.0 oz).
The adult acorn woodpecker has a brownish-black head, back, wings and tail, white forehead, throat, belly and rump. The eyes are initially dark in fledglings, turning to white within a few months. There is a small part on the small of their backs where there are some greenish feathers. In most subspecies, adult males have a red cap starting at the forehead, whereas females have a black area between the forehead and the cap. The white neck, throat, and forehead patches are distinctive identifiers. When flying, they take a few flaps of their wings and drop a foot or so. White circles on their wings are visible when in flight. Acorn woodpeckers have a call that sounds almost like they are laughing.
The acorn woodpecker's habitat is forested areas with oaks in the coastal areas and foothills of Oregon, California, and the southwestern United States, south through Central America to Colombia. This species may occur at low elevations in the north of its range, but rarely below 1,000 m (3,300 ft) in Central America, and it breeds up to the timberline. Nests are excavated in a cavity in a dead tree or a dead part of a tree.
Acorn woodpeckers, as their name implies, depend heavily on acorns for food. Acorns are such an important resource to the California populations that acorn woodpeckers may nest in the fall to take advantage of the fall acorn crop, a rare behavior in birds. Acorns are stored in small holes drilled especially for this purpose in "granaries" or "storage trees"--usually snags, dead branches, utility poles, or wooden buildings. Storage holes--always in dead tissue such as bark or dead limbs--are used year after year, and granaries can consist of thousands of holes, each of which may be filled by an acorn in the autumn. Access to acorn crops influences the composition of acorn woodpecker communities. In one study in New Mexico, there were about 90% of non-breeding adults per social unit in 1976, a year of a poor acorn crop. The following year, 1977, there was a significant increase in acorn production and a correlating decrease in non-breeding adults per unit.
Although acorns are an important back-up food resource, acorn woodpeckers primarily feed on insects, sap, and fruit. They can be seen sallying from tree limbs to catch insects, eating fruit and seeds, and drilling holes to drink sap.
The woodpeckers then collect acorns and find a hole that is just the right size for the acorn. As acorns dry out, they are moved to smaller holes and granary maintenance requires a significant amount of the bird's time. The acorns are visible, and a group defends its granary against potential cache robbers like Steller's jays and western scrub-jays.
In some more tropical parts of its range the acorn woodpecker does not construct a "granary tree", but instead stores acorns in natural holes and cracks in bark. If the acorn crop is poor and birds cannot find enough to store, the woodpeckers will move to other areas over the winter.
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