With their long legs, very short neck and tail,s and short rounded wings, gnat eaters have the appearance of a dumpy, tailless robin. The males of most species have a distinctive tuft of often very long white or silvery-white feathers behind their eyes the females sometimes have a similar but less conspicuous tuft.
The eight species of gnat eaters are distributed across most of Brazil and adjacent countries, but few species overlap. Even where the ranges of two species do overlap, they often occupy different habitats. They are mainly ground-dwelling forest birds and although it is relatively easy to call them into view, they normally skulk in dense undergrowth.
When approached Rufus gnat eaters give sharp alarm calls very different from their melodious, if simple, song: a series of short whistles gradually increasing in pitch and volume. Other species have similar vocalizations and males of some species can produce harsh sounds with their wings.
Alone or in pairs they work through leaf litter or low vegetation feeding on relatively small insects. The nest is placed close to the ground and made mainly of large leaves and lined with softer plant fibers. Both sexes incubate and will feign injury if disturbed at the nest.
The two species of ant pipit (Corythopis) used to be included in the gnat eater family, but they have a little general resemblance to the gnat eaters and are now placed with the tyrant flycatchers.
The tapaculos occur mainly in the cooler humid parts of South America at altitudes above 1, 000m (3, 3ooft). Only in the south do they occupy lowland habitats. Although seven genera are restricted to the tropical belt, the greater number of species is in the temperate southern Andes. Only Scytalopus, by far the largest genus with z I species, spans almost the entire range of the family.
Perhaps the most distinctive feature oftapaculos is a large movable flap covering the nostrils. They are rather compact with short rounded wings and large strong feet and legs. The most distinctive species is the ocellated tapaculo of the northern Andes: it is strikingly patterned, has a very heavy bill, which is markedly flattened on top, Anda a very long straight hind claw. Most other species are rather drab and wren-like, par-secularly in that the tail is usually raised, often lying almost along the bird’s back. The tail is usually short but is long in genera such as the bristle fronts of eastern Brazil.
Tapaculos skulk in thick vegetation. Rarely leaving the ground, they walk (or run rapidly) scratching among ground littering in search of invertebrates and occasional plant material. The difficulty of seeing themes is compensated for by their loud and often weird songs. Some species (egg the twobristlefronts and the two huet-huets) are quite musical, but others (especially many of the Scytalopus species) produce character-is tic monotonous repetitions of one or two unmusical notes.
Nests are usually on or close to the ground, sometimes several meters up in the undergrowth or in tree hollows, while some(egg the two Scelorchilus species) dig nest burrows. Most nests are domes with a small side entrance, although some of the hidden nests are cup-shaped. Eggs are relatively large and round and are incubated by both parents.
The sharp bill has a wide but curiously dies-continuous distribution from southern Brazil to Costa Rica, with some variation in plumage and voice. Despite being widely distributed and reasonably common in some areas, its tendency to be a solitary bird of rain and cloud forest (from 400-1,800m, 1, 3 00-6,000ft) keeps it poorly known. Events’ status as a one-species family is uncertain.
It is a strong direct flier. The male has a serrated edge on his outer primary feathers which may be used to produce sound; button sound has been associated with the bird’s curious display flight. In parts of south Brazil its long thin whistle, smoothly descending from a very high pitch, can be frequently
Heard in good, usually, montane forest. It generally stays high in the canopy. It w’.11move around in a tit-like fashion in the outermost leaves of the canopy, often hang-in upside-down to pick invertebrates from leaf clusters or rolled leaves. It will also hang on bunches of small fruits to feed, rejecting many of the hard stones. Its peculiar sharp bill and short strong legs are well-adapted to these feeding techniques. It was saddled onto a small horizontal branch near the top of the canopy of one of the tallest trees in the area. It was a shallow cup of roughly interwoven leaf stalks with a few leaves.
The outer sure-face had a thin coat of mosses, liverworts, and spiders’ webs secured with a dried saliva-like substance. Young was fed by regurgitation of small fruit and invertebrates. Only one parent was ever in attendance and was thought to be female: certainly, birds singing in the breeding season show no interest in nesting activities.
Plant cutters are a small group of South American species of uncertain affinities. Their bill, which earns them their name, has finely serrated edges and is used to pluck and cut buds and tender leaves as well as fruits and seeds. With short rounded wings and relatively long tails, they have a heavy undulating flight, usually keeping close to tithe ground. Although usually occurring singly or in pairs, numbers may accumulate in orchards and small parties of up to six or more occur in winter.
Away from any conflict with man.
They live in wooded mountain valleys to an altitude of 3,000m (Io, 000ft) and on prairie interspersed with bush (especially thorns and trees. The southern populations of the White-tipped plant cutter. The smallest and brightest species migrate to winter in the bushy pastures of northeast Argentina and Uruguay. The Peruvian plant cutter. The dullest and most tropical species are more sedentary.
From high in bushes and trees. The males sing an unmusical song. That of the White-tipped being likened to tree branches rub-bang together, to sheep bleating, or frogs croaking, with other discordant squeaks. Sometimes they make a slow display flight with very rapid wing beats. The Rufus-tailed plant cutter produces a rasping trill. The White-tipped nests inside thick, thorny bushes, or even cacti, but the Rufous-tailed normally nests in tree forks (often in fruit trees). At least in the White-tipped plantcutter most of the care of the nest and the youngish is performed by the female, who may raise two broods. Plant cutters have been recorded as hosts to the parasitic Shiny cowbird.
New Zealand wrens are a small, obscure family of three species with no known affinity to other groups of birds. There was
Once a fourth species, the Stephen Island wren may have been flightless. It was discovered in 1894 when a light housekeeper’s cat carried in i5 specimens. The coat is assumed to have destroyed the entire remaining population.
The three living species are the Rock wren, the Bush wren, and the rifleman; none is a strong flier. Having lived for so long in the absence of predators they have been ill able to cope with new predators introduced by man and with modification of their habitat. They have a stocky appearance, with large shanks and toes, and almost no tail. Their bill is slender, about the same length as the head: in the rifleman, it is slightly upturned. They have soft plumage and short, rounded wings.
The Bush wren and the Rock wren are thought to be examples of an indigenous genus that developed two forms, the former inhabiting vegetation at low altitudes, and the latter living in alpine vegetation.
The Rock wren occurs on the mountainous divide of South Island at altitudes between you and 2,500M (3,000-8,000ft), preferring sparsely vegetated rock and holder screeds and moraines. It eats mainly insects, foraging for them in cracks and crevices, under holders, and in short, tight plant swards, even when these are covered with snow (in which case the bird moves through air spaces between the snow and the ground surface). It also uses crevices and holes for nest sites and caching food. Rock wrens occupy well-defined territories, using three-note calls to advertise the location of their boundaries.
The Bush wren, of which there are three subspecies, could now be extinct in the North and South Islands. As a weak flier, nesting in holes near the ground, it was par-secularly vulnerable to habitat changes wrought by man and mammal predators introduced by man.
Under modern conditions, it is the rifle-man that has fared best of all the New Zeal-land wrens. One of its main habitats, beech forest, remains abundant on both main islands and it has begun to enter cultivated areas. It is slightly more secure than the Bush wren because it nests in holes with tiny openings high in tree trunks.
The rifleman is one of the smallest birds in New Zealand. But a female’s egg weighs about 20 percent of her body weight, and since she lies every other day and a com-plate clutch are five eggs a female produces, in nine days, her body weight is in eggs. This combination probably explains some of the factors influencing the rifleman’s breed-in characteristics.
Most of the nest building is undertaken by the male rifleman who also increases his mate’s intake of food during the days before and during egg-laying by bringing her up to nine food items an hour. Between the laying of each egg, there are two days. The young hatch in an undeveloped condition and then take longer
Than usual to develop: the breeding cycle forgone clutch may take up to 6o days. After the clutch has been laid the male undertakes most of the daytime incubation and is also more active than the female in feeding the young, though this may be done with the assistance of other adults (see box). The young birds put: on a lot of weight: before fledging they may be considerably heavier than their parents.
Before the young of the first clutch has left the nest their parents have usually started building a nest for a second clutch. This time the breeding pattern differs slightly from the first one, due to the con-tinning demands of the first brood on the parents. The nest is smaller, loosely built, and often unlined. In the period of egg production and during incubation the male does not bring extra food to the female. The size of the second clutch is on average one egg smaller than the first. After all, eggs have been laid there is sometimes a pause of several days before incubation begins, probably because the parents are still feeding deepen-dent young from the first clutch.
Sunbird amities have two well-known features: differences between the two genera and similarities between false sunbirds with true sunbirds. Their ecology and behavior however are little known. The amities have been described as “quiet” and “sluggish” with a limited vocal repertoire. They are thought to eat fruit but probably take insects as well. It has been suggested that the False sunbirds’ conspicuous long, curved, and tapered bill is an adaptation for feeding on nectar and has evolved in the virtual absence of competitors that exploit flowers for nectar and possibly pollen. False sunbirds have a specialized tongue similar to that of other nectar feeders which supports this view. However, few field data exist indicating the feeding preferences of false sunbirds.
The radically different bills and dissimilar plumage of the sunbird amity genera illustrate the wide radiation that has occurred in the family and suggests that intermediate genera may have existed in the past. Indeed Madagascar is well known forth the relatively recent extinction of both birds and other animals. The development of obvious differences between false sunbirds and amities has been paralleled by the evolution of striking similarities with true sunbirds. These similarities include their tubular tongue, bill shape, and biannual molt.