Species accounts

Rifleman

Acanthisitta chloris

SUBFAMILY TAXONOMY

Acanthisitta chloris Sparrman, 1787. OTHER COMMON NAMES

French: Xenique grimpeur; German: Grenadier; Spanish: Reyezuelo de Nueva Zelanda Fusil.

PHYSICAL CHARACTERISTICS

The riflemen, the smallest living bird species in New Zealand, averages about 3 in (8 cm). There is considerable sexual dichromatism and dimorphism. The female is larger than the male, an odd reversal of the normal state of affairs in bird life. Male dorsal parts are bright yellow-green above; female dorsal parts are striped darker and lighter brown and riddled with red-brown flecks. Both sexes have white ventral parts, white superciliary streaks, and yellowish rumps and flanks. The wings each sport a yellow bar and a white spot posterior to the bar. Bills of both sexes are slightly upturned, the female's a little more emphatically.

DISTRIBUTION

The rifleman is the most cosmopolitan of Acanthisittidae, fairly common and at home throughout most of lowland New Zealand, including the lower two-thirds of North Island, all of South Island, Stewart Island (off the southeast coast of South Island), and the Great Barrier and Little Barrier Islands.

Acanthisitta chloris I Resident

Some ornithologists recognize two subspecies—South Island rifleman (Acanthisitta chloris chloris) and North Island rifleman (Acanthisitta chloris granti)—although the two differ only slightly in color, granti trading chloris's yellow rump for a greenish one.

HABITAT

The rifleman thrives easily in various habitats, including forests, farmlands, disturbed and regenerating habitats, and scrublands. It has even adapted well to landscapes partly composed of non-native plant species.

BEHAVIOR

Riflemen are lively, diurnal birds. The call is a sharp, high-pitched, cricket-like zipt, single or in a rapid staccato. Birds spend their days foraging in trees, winging from one to another, usually over an accustomed route, and only rarely on the ground. A rifleman sometimes displays an odd behavior that Acanthisittidae alone may claim as theirs: an individual will perch on a branch and energetically flick its wings, as if showing off.

FEEDING ECOLOGY AND DIET

Sexual dichromatism relates to feeding methods. Both sexes feed on insects, spiders, and other small invertebrates, but they split up feeding strategies. The male gleans from the leaves of a tree while the female works the bark, both going about their work meticulously and minutely. Thus, either sex has proper camouflage for its particular gleaning grounds. The female's slightly more upcurved bill may give her an advantage in poking into and prying at loose bark.

REPRODUCTIVE BIOLOGY

Male and female form strong, long-lasting pair bonds. Pairs breed August-January; females lay 2-4 white eggs. A typical pair builds a rather elaborate nest in a tree crevice, sometimes with a dome-like roof, floored and wallpapered inside with spider webs and mosses. The male feeds the brooding female and both parents feed chicks. A bonded pair typically fledge two broods in one season, fledged chicks of the first brood often pitching in to help feed chicks of the later brood.

CONSERVATION STATUS

The species is widespread, fairly common, and protected by law. It is not threatened.

SIGNIFICANCE TO HUMANS None known. ♦

Stephens Island wren

Xenicus lyalli

TAXONOMY

Xenicus lyalli Rothschild, 1894. OTHER COMMON NAMES

English: Stephens wren; French: Xénique de Stephen; German: Stephenschlüpfer; Spanish: Reyezuelo de Stephen.

PHYSICAL CHARACTERISTICS

A typical individual was 4 in (10 cm). Both sexes were colored similarly, the female being merely duller. Both had small but

Xenicus lyalli H Resident stout, strong bills. The lower mandible was light brown, as were legs and feet, the upper mandible dark brown with a horn-colored tip. The tail was little more than a stub. Although the overall body color was brown, the superciliary streak, chin, and throat were greenish yellow. Light-brown feather margins on partly overlapping body feathers decorated male and female with rows of roundish, fuzzy-edged spots on a darker brown backround. Rows, parallel to one another while following body contours, ran head to tail and covered the entire body, lending the birds a passing resemblance to pinecones. The female's spots were more softly applied.

DISTRIBUTION

The species inhabited only this small island, a mere 100 ft (30.5 m) square, but steep-sided, with an elaborate ecology.

HABITAT

Steep, rocky outcroppings; a small forest, grass, and scrub. BEHAVIOR

All that is known about this species, including its behavior, was recorded by a single person, George Lyell. The birds ran and skittered about on the ground, similar to mice, whose niche the birds likely filled. The species could not fly, or flew very little and ineffectively—a handy adaptation to life on a very small island, but marking them for certain death from introduced predators. The short, rounded wings and soft plumage attest as well to diminished or lost powers of flight. The voice was never described.

FEEDING ECOLOGY AND DIET

The wrens were apparently most active during twilight hours and may have been nocturnal. They would emerge from holes in rocks and spend some time poking about, alternately running about and hiding, most likely hunting for small arthropods.

REPRODUCTIVE BIOLOGY

Unknown.

CONSERVATION STATUS

The Stephens Island wren is emphatically extinct. Its discovery and extirpation are a masterpiece of cruel irony. The birds went unnoticed and were safe until the New Zealand government built a lighthouse on the islet and in 1894 staffed it with George Lyell, who brought his cat, Tibbet, to the island with him. The consequences are predictable. Within a few months, Tibbet killed, then ate or brought home as show-off gifts for his master, the entire population of Stephens Island wrens. Lyell sent nine corpora to prominent ornithologists Walter Lawry Buller and Walter Rothschild, who declared them a previously unknown species of New Zealand wren. By the time the glad news reached Lyall, the wrens were extinct. As if in a final petulant jest, the birds were scientifically dubbed Traversia lyalli, later changed to Xenicus lyalli, after the owner of the cat who wiped them out. Ten specimens still exist, distributed throughout five museums.

SIGNIFICANCE TO HUMANS

Among biologists and conservationists, the Stephens Island wren has become a poignant symbol of the fragility of isolated island species with limited space and populations. ♦

Resources

Books

Flannery, Tim, and Peter Schouten. A Gap in Nature:

Discovering the World's Extinct Animals. New York: Atlantic Monthly Press, 2001.

Moon, Geoff. The Hand Guide to the Birds of New Zealand. Mechanicsburg, PA: Stackpole Books, 1999.

Robertson, H. A., B. D. Heather, and D. J. Onley. The Reed Field Guide to New Zealand Birds. Oxford: Oxford University Press, 2001.

Sibley, C. E., and J. E. Ahlquist. The Phylogeny and Classification of Birds: A Study in Molecular Evolution. New Haven: Yale University Press, 1991.

Worthy,Trevor H., R. N. Holdaway, and Rod Morris. The Lost World of the Moa: Prehistoric Life of New Zealand. Bloomington: Indiana University Press, 2002.

Periodicals

Cracraft, Joel. "Gondwana Genesis." Natural History. Dec 2001-Jan 2002

Feduccia, A. "Morphology of the Bony Stapes in the Menuridae and Acanthisittidae: Evidence for Oscine Affinities." Wilson Bulletin. 87 (1975): 418-420.

Feduccia, A., and S. L. Olson. "Morphological Similarities between the Menurae and Rhinocryptidae, Relict Passerine

Resources

Birds of the Southern Hemisphere." Smithsonian Contributions to Zoology. 366, iii (1982).

Hunt, G. R., and I. G. McLean. "The Ecomorphology of Sexual Dimorphism in the New Zealand Rifleman, Acanthisitta chloris." EMU: Austral Ornithology. Vol. 93 (1993): 71-78.

Sibley, C. G., Williams, G. R., and J. E. Ahlquist. "The Relationships of New Zealand Wrens (Acanthisitiidae) as Indicated by DNA-DNA Hybridization." EMU: Austral Ornithology. 84 (1982): 236-241.

Organizations

The Ornithological Society of New Zealand. P.O. Box 12397, Wellington, North Island New Zealand. E-mail: [email protected] Web site: <http://osnz.org.nz>

Other

New Zealand Birds <http//www.nzbirds.com>

Payne, Robert B. Bird Families of the World: A Resource of the University of Michigan Museum of Zoology, Bird Division <http://www.ummz.lsa.umich.edu/birds/birddivresources/ families.html>.

Kevin F. Fitzgerald, BS

Ovenbirds

Class Aves

(Furnariidae)

Order Passeriformes Suborder Tyranni (Suboscines)

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Family Furnariidae

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Thumbnail description

Small to medium-sized, brownish colored,

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insectivorous songbirds

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Size

Body length 5-11 in (13-28 cm)

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Number of genera, species

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34 genera; about 218 species

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Habitat

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Occur in forests of various types, brushlands,

pampas (grasslands), alpine habitats, and semi-

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Conservation status

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Critically Endangered: 3 species; Endangered: 9

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species; Lower Risk: 18 species, Vulnerable: 15

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species.

Distribution

Range from central Mexico to southern South America

Evolution and systematics

The ovenbirds (Furnariidae) are a family of songbirds within the extremely diverse order of perching birds (Passer-iformes). They are most closely related to the woodcreepers (Dendrocolaptidae), ant thrushes (Formicariidae), cotingas (Cotingidae), manakins (Pipridae), and tyrant flycatchers (Tyrannidae). Some avian taxonomists consider the wood-creepers to be a subfamily of the Furnariidae, naming them as Dendrocolapinae. The family is divided into three subfamilies. The true ovenbirds (Furnariinae) are about 40 species of long-legged songbirds found predominantly in southern South America that nest on the ground or use moist soil for nestbuilding. The bushcreepers (Synallaxeinae) are 95 species of small birds found mainly in tropical South America, often with a fringed or long tail; they build a ball-like nest. The leafcreep-ers (Philydorinae) are 84 species found predominantly in tropical America that forage on tree-trunks or in foliage and usually build their nest in an excavated tunnel.

Physical characteristics

Species in the ovenbird family have a range of body length of 5-11 in (13-28 cm). Their wings are relatively short, and may be rounded or pointed at the tips. The legs and feet are of medium length, and the front toes are joined at the base. The bill is slender, short to long, and pointed. They usually have a brownish, relatively inconspicuous coloration on the back, and range from light to brown-and-white speckled or streaked on the belly. Many species have a white throat. They have a light stripe over the eye, known as a superciliary line. The wing bands are often brownish red or white. The sexes are usually similarly colored.

Distribution

Species in the ovenbird family range from central Mexico to Patagonia in southern South America.

Wing-banded hornero (ovenbird) (Furnarius figulus) at its nest in Brazil. (Photo by Anthony Mercieca. Photo Researchers, Inc. Reproduced by permission.)

Habitat

Ovenbirds are non-migratory birds that inhabit forests of various kinds as well as brushlands, pampas (grasslands), alpine habitats, and semi-desert.

Behavior

Ovenbirds may occur as solitary individuals or as a breeding pair, or sometimes in small groups. Some ovenbirds occur with other birds in mixed-species foraging flocks. They occur on the ground and in trees; the ground-foraging species tend to walk and hop, while some of the arboreal species forage acrobatically within foliage and finer branches, and others on tree-trunks. The flight of some species is rather weak, but it is strong in others, although not over a long distance. The calls are harsh and scolding, and the song consists of series of whistles and trills.

Feeding ecology and diet

Ovenbirds feed mostly on insects, spiders, and other invertebrates. Some species also eat small seeds. They forage among litter on the ground or in foliage and on bark and epiphytes of shrubs and trees.

Reproductive biology

The nests of ovenbird species are extremely variable in their shape and mode of construction. Many species build a loose nest of plant fibers inside of a natural cavity in a tree or among rocks. The birds that are actually called "ovenbirds" are species in the genus Furnarius; these species are also called horneros, Spanish for "a baker of bread." Their nest is built by both members of a breeding pair and is made of thousands of lumps of moist clay, each about 0.1 oz (3 g) in weight and carried to the nest-site in the bill. Initially, a nest-base of varying thickness is built, depending on the nature of the supporting structure beneath, which is often a stout tree branch, but may also be on the ground. Next, the pair of birds builds the outer walls, which are then joined to form a roof, thus creating a structure that superficially resembles an oven. An entrance hole is left on one of the sides to permit access to the nest cavity, which is lined with fine fibers of grass and other plant tissues. Nests typically weigh about 10 lb (4 kg), but they can weigh as much as 15 lb (6.8 kg). One pair of ovenbirds may work on constructing as many as four nests at a time, either working together on all of them or each bird making only one. At the beginning of the egg-laying season, however, usually only two nests are completed and ready for use for breeding or roosting. Often other species of birds, such as swallows, use abandoned ovenbird nests for their own breeding.

The miners (Geositta) dig tunnels 3-10 ft long (1-3 m) into an earthen bank or cliff. Spine-tails (Synallaxis) build small, spherical, hanging nests in trees, which are entered through a hole from below. Canasteros (Asthenes) build a huge, roughly spherical nest about 14 ft (4 m) high in a tree. The nest is about 15-17 in in diameter (40 cm) and is entered by a hole on the side. Thornbirds (Phacellodomus) build the largest nests, which can be 3 ft (1 m) high, spherical, and made of twigs. It often contains several chambers, all of which are entered from below.

Species in the ovenbird family lay two to six eggs that are usually colored white, or sometimes blue or greenish. Both parents share in the incubation of the eggs and in the care of the nestlings and fledglings.

Conservation status

The IUCN lists 45 species of ovenbirds as being at risk. Critically Endangered species are the royal cinclodes (Cinclodes

Rufous hornero (ovenbird) (Furnarius rufus) at its nest in Brazil. (Photo by Erwin & Peggy Bauer. Bruce Coleman Inc. Reproduced by permission.)

aricomae) of Bolivia and Peru, the Alagoas foliage-gleaner (Phi-lydor novaesi) of Brazil, and the plain spinetail (Synallaxis in-fuscata) of Brazil. Endangered species are the Cipo castanero (Asthenes luizae) of Brazil, the Bolivian spinetail (Cranioleuca henricae) of Bolivia, the white-browed tit-spinetail (Leptas-thenura xenothorax ) of Peru, the hoary-throated spinetail (S. kollari) of Brazil and Guyana, the blackish-headed spinetail (S. tithys) of Ecuador and Peru, the Bahia spinetail (S. whitneyi) of Brazil, the russet-bellied spinetail (S. zimmeri) of Peru, the russet-mantled softtail (Thripophaga berlepschi) of Peru, and the striated softtail (T. macroura) of Brazil. Most of the designated species at-risk have declined in range and abundance because of the conversion of their habitat into agricultural or residential land-uses, or habitat degradation associated with timber harvesting or other disturbances. These same sorts of stres-

sors are also affecting many other species in the family and are causing them to decline in range and abundance, but not yet to the degree that they are considered to be at-risk.

Significance to humans

The rufous hornero (Furnarius rufus) is the national bird of Argentina, in popular recognition of its bold and jaunty demeanor; thus, it is of some cultural significance. Other than this species, members of the ovenbird family are not of much direct importance to humans. They are an interesting and diverse group of birds, however, and viewings of them are widely sought by birdwatchers and other naturalists, resulting in local economic benefits through ecotourism.

Thornbird Bird Species Africa

1. Bar-winged cinclodes (Cinclodes fuscus); 2. Coastal miner (Geositta peruviana); 3. Scale-throated earthcreeper (Upucerthia dumetaria); 4. Bolivian earthcreeper (Ochetorhynchus harterti); 5. Thorn-tailed rayadito (Aphrastura spinicauda); 6. Des Murs's wiretail (Sylviorthorhynchus desmur-sii); 7. Striolated tit-spinetail (Leptasthenura striolata); 8. Campo miner (Geobates poecilopterus); 9. Rufous hornero (Furnarius rufus); 10. Band-tailed earthcreeper (Eremobius phoeincurus). (Illustration by Jonathan Higgins)

1. Wren-like rushbird (Phleocryptes melanops); 2. Rufous-tailed xenops (Xenops milleri); 3. Mouse-colored thistletail (Schizoeaca griseomurina); 4. Pale-breasted spinetail (Synallaxis albescens); 5. Streak-capped spinetail (Cranioleuca hellmayri); 6. Great spinetail (Siptornopsis hypochon-driacus); 7. Greater thornbird (Phacellodomus ruber); 8. White-throated treerunner (Pygarrhichas albogularis); 9. Rufous-necked foliage-gleaner (Syndactyla ruficollis); 10. Cinnamon-rumped foliage-gleaner (Philydor pyrrhodes); 11. Short-billed leaftosser (Sclerurus rufigularis). (Illustration by Jonathan Higgins)

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