Bowerbirds

(Ptilonorhynchidae)

Class Aves

Order Passeriformes

Suborder Passeri (Oscines)

Family Ptilonorhynchidae

Thumbnail description
Medium-sized, thrush-like, stocky, strong-footed, and typically stout-billed songbirds. Family includes sexually and cryptically monochromatic to dramatically sexually dichromatic species. Bowerbirds are renowned for the bower building behavior of males of polygynous (one male mated with two or more females) species.

Size
8.7–14.6 in (22–37 cm); 0.18–0.64 lb (80–290 g)

Number of genera, species
8 genera; 20 species

Habitat
Rainforests, moss forests, wet sclerophyll (Australian vegetation with hard, short, and often spiky leaves) forests and woodlands, savanna, rocky wooded gorges, and open woodlands to semi-desert

Conservation status
Vulnerable: 1 species; Near Threatened: 1 species

Distribution
Mainland New Guinea and Australia and offshore islands

Evolution and systematics

Bowerbirds have long been closely associated with birds of paradise (Paradisaeidae) but evidence of a major dichotomy between the two groups in anatomical and biological traits is supported by several molecular studies. Bowerbirds are part of an Australasian radiation thought to have occurred during the past 60 million years. They diverged from lyrebirds (Menuridae) and scrub birds (Atrichornithidae) about 45 million years ago (mya). Results of molecular studies place the separation of bowerbirds (superfamily Menuroidea) from birds of paradise and other corvines (superfamily Corvoidea) at 28 mya and indicate that major lineages within them arose 24 mya.

Satins (Ptilonorhynchus violaceus) are the only bowerbirds known from fossil sites; found in Victoria, Australia, two are from the Holocene and one is from the Pleistocene. These fossils are from locations remote from the present wet forest range of the species and attest to a previously more extensive distribution of Australian subtropical rainforests.

The Ptilonorhynchidae comprises 20 species of compact, robust, oscinine songbirds. Three species of socially monogamous and territorial catbirds belong to the genus Ailuroedus. The 17 known or presumed polygynous species consist of one Scenopoeetes, four Amblyornis, one Archboldia, one Prionodura, four Sericulus, one Ptilonorhynchus, and five Chlamydera species.

Physical characteristics

Bowerbird morphology and anatomy are broadly typical of oscinine passerines with the exception of a few traits. Typical songbirds have 9–10 secondaries (including tertials), but bowerbirds have 11–14. Bowerbirds also have an enlarged lachrymal (part of the skull cranium, near the orbit) that is paralleled only in the Australian lyrebirds (Menuridae). Bowerbirds have high average survivorship, and some individuals live for 20–30 years.

Within the family, great bowerbirds (Chlamydera nuchalis) are the largest and golden bowerbirds (Prionodura newtoniana) are the smallest. Males are typically, but not always, heavier and are larger in most body measurements than females. Juveniles and immature bowerbirds are generally smaller in wing length and weight than adults. The bill is typically stout and powerful; exceptions are the fine and longer bill of regent bowerbirds (Sericulus chrysocephalus) and the falcon-like toothed mandibles of tooth-billed bowerbirds (Scenopoeetes dentirostris). Legs and feet are stout, powerful, and scutellate.

The family exhibits 50–60 different plumages. Catbirds are sexually and cryptically monochromatic, and both sexes of the polygynous tooth-billed, Vogelkop (Amblyornis inornatus), and Chlamydera bowerbirds are nearly identical. The other polygynous species are sexually dichromatic, with adult males adorned with colorful and ornate plumages and females

being drab (some are barred ventrally). Juvenile and immature male plumages are similar to those of adult females. Males take five to seven years to fully acquire adult plumage.

Legs and feet are typically dark brown, olive-brown, olive, blue-gray, or black. Mouth color can be black, pale yellow, or orange-yellow depending on species. The skin of nestlings is pinkish, orange-pink, or pale flesh colored. Bill color is typically dark brown to black but can be pale or sexually dimorphic in some species. Iris color is typically pale to dark brown but is red in adult catbirds, whitish in Sericulus, and blue in Ptilonorhynchus.

Distribution

Ten species are confined to New Guinea and eight to Australia, and the two remaining species occur on both. Bowerbirds are mainly confined to the tropics and subtropics; only satin bowerbirds extend significantly into and across temperate regions. The Australian Chlamydera are mainly lowland dwelling but species in New Guinea occur up to 5,900 ft (1,800 m) altitude. Because of the vast mountain ranges, forest-dwelling New Guinea bowerbirds segregate by altitude. Only white-eared (Ailuroedus buccoides) and black-eared (A. melanotis) catbirds and great bowerbirds occupy continental islands.

Habitat

Species of Ailuroudus, Scenopoeetes, Amblyornis, and Prionodura are predominantly confined to rainforests and Archboldia to moss forests. Species of Sericulus and Ptilonorhynchus occur in rainforest but also at rainforest edges, and the latter species within adjacent wet forests and woodlands. The Chlamydera bowerbirds are adapted to more open, drier, riverine forests, forest/grassland ecotones, open woodland, savanna, and almost desert.

Behavior

The family includes species with socially monogamous and polygynous mating systems. Monogamous pairs of catbirds defend an all-purpose territory. Males do not assist with nest building, incubation, or brooding of nestlings (which they do feed). The promiscuous males of the 17 polygynous bowerbirds defend only the immediate area of their bowers. A seasonal hyperabundance of fruits permits promiscuous males to spend inordinate amounts of time at their courts, in attracting/courting females, while also permitting females to nest and provision their offspring unaided.

Uniquely within the avian world, promiscuous males clear court areas and skillfully build complex symmetrical structures of sticks, grasses, or other vegetation, and decorate them. Three types of modified courts are: cleared and leaf-decorated courts, maypole bowers, and avenue bowers. Maypoles consist of branches and/or saplings with accumulations of orchid stems or sticks and an elaborate and decorated discrete mat beneath it. Avenues consist of two parallel walls of sticks or grass stems placed vertically into a foundation that is laid on a ground court that may extend beyond one or both ends of the bower to form a platform.

Male bowerbirds decorate courts and bowers with items such as leaves, flowers, fruits, lichens, beetle wing cases, insect skeletons, tree resin, snail shells, bones, river-worn pebbles, and specific parrot tail feathers and nuptial plumes of adult males of certain birds of paradise. Charcoal, glass, and innumerable other man-made objects may also be used. Males of some species manufacture and apply paint to bowers, even holding a wad of vegetable matter in the bill tip to use as a tool to apply paint. Because of this complex behavior, bowerbirds have been associated with high intelligence and artistic abilities.

Courts and bowers are located on favored topography exhibiting one or more micro-environmental features required by males. Bower sites are occupied for decades, and adult males exhibit long-term (one or more decades) fidelity to them. Immature males spend an apprenticeship of five to six years visiting rudimentary, or practice, courts or bowers of their own construction and bowers of adult males to acquire skills for better bower building, decorating, and displaying to attract females.

Courts and bowers are critical to male reproductive success in the polygynous species. They provide a focal point to which males attract females for courting and mating. Adult males of most species average 50–70% of daylight at their bower sites. Activities at bower sites involve vocalizations (advertisement song and other calls, including mimicry), bower maintenance (building, decorating, painting), display, and chasing unwanted conspecifics away. Rival males damage each others bowers and/or steal favored decorations, in so doing improving their own chances of attracting more potential mates.

Sexual selection, through mate choice by females, is fundamentally important to the evolution of elaborate display traits (ornate plumage and/or bower complexity/decoration) of bowerbirds. In some species colorful and elaborate display plumage has been lost and replaced by, or transferred to, a bower structure and its decorations. Discerning females assess the frequency and intensity of male bower attendance, the quality and/or quantity of bowers and decorations, displays, plumage, and vocalizations before soliciting the male of their choice. It is the older males, those with greater experience, skills, and survival, that are typically selected as mates by females.

Feeding ecology and diet

While typically omnivorous, several bowerbirds are more specialized in having a predominantly fruit diet supplemented by arthropods and other animals such as worms, frogs, skinks, and birds. Flowers, leaves, sap, and few seeds may also be eaten. Unlike birds of paradise, bowerbirds do not use their feet to hold and manipulate food.

Bowerbirds do not digest seeds but act as true seed dispersal agents to the plants on which they feed. The traditional nature of bower sites suggests that a local abundance of food plants might result from the germination of seeds defecated by the birds. Catbirds store or cache fruits about their territories, and males of some polygynous species do so about their bower sites.

Reproductive biology

Courtship of monogamous catbirds is simplistic; a male chases a female through tree foliage to then hop and bounce between perches in front of her before mating. Courtship of most polygynous bowerbirds is far more complex and is typically instigated by the arrival of a female at a bower site, after which the male moves away from the visitor in a ritualized fashion and/or hides from her view while producing a subsong that includes vocal mimicry of other bird calls and

environmental sounds. Male regent bowerbirds differ in initiating courtship by leading females to their bower from the forest canopy, where they had advertised their location by bright plumage rather than by calls. Courtship display typically commences on the bower court. Females signal their readiness to mate by solicitation posturing. Copulation usually takes place on the bower court, mat, or platform, or within the avenue.

The same nest location, even the specific site, is sometimes used each year by catbird pairs or by the same female of a polygynous species. Nests typically consist of a stick foundation with a nest-cup of dried leaves and twigs atop this and within which a discrete cup lining of finer material holds the clutch.

Elliptical eggs are pale and unmarked in Ailuroedus, Scenopoeetes, Amblyornis, Archboldia, and Prionodura and colored and vermiculated in Sericulus, Ptilonorhynchus, and Chlamydera. Clutch size is one to three eggs for both monogamous and polygynous bowerbirds. Eggs are laid on alternate days, with incubation usually starting with clutch completion. Renesting occurs following a nest loss, but there is no evidence of two broods being raised in a single season.

Depending on species, incubation lasts 21–27 days and the period lasts 17–30 days. Bowerbirds do not regurgitate meals to nestlings, unlike birds of paradise.

Details of nestling growth and development are known only for Ailurodus, Archboldia, and Prionodura. Nestlings of monogamous parents grow faster than those with only a female parent and also leave the nest when smaller as a proportion of adult size. Nestling bowerbirds fledge well feathered in a plumage similar to that of adult females, with some down remaining on the crown and elsewhere. After leaving the nest, bowerbird offspring depend on their parent(s) for 40–60 days or more. Proportions of successful nests, eggs, and nestlings are greater in monogamous than in polygynous species.

Nesting seasons in New Guinea are poorly known. Bowerbirds nest during the latter part of the dry season (late August through September) in Australian rainforests when temperatures, rainfall, and food resources are increasing. Egg laying peaks during October through December. Fruit and arthropod abundance reach a peak during hotter, wetter, months as females provision nestlings/fledglings (and adults begin their annual molt).

Conservation status

While several Australian species have lost parts of previously more extensive ranges to habitat destruction/degradation, none is rare or endangered as a species. A subspecies of western bowerbirds (Chlamydera guttata carteri) may be Near Threatened because of its highly restricted range. Adelbert bowerbirds (Sericulus bakeri) are listed as Vulnerable and Archbolds's bowerbird (Archboldia papuensis) are listed as Near Threatened. In addition to habitat destruction, the spread of domestic/feral cats and other exotic vertebrates through New Guinea forests may represent a threat to bowerbird populations.

Significance to humans

A few New Guineans and Australian aboriginals have long worn the crests of adult male Amblyornis and Chlamydera species respectively as personal adornment. Papuan men perceive male bowerbird activities as equivalent to their own efforts in seeking to attract and pay for a bride. Some aboriginal people respect male bowerbirds as avian custodians of ceremonies involving secret business (rites) of their own. They believed that Chlamydera species steal the bones of people for their own ceremonial purposes, and so birds and bowers are

unmolested. Because birds take items from human middens as decorations they may influence the interpretation of archaeological assemblages. Of the 20 species, eight have been bred in aviaries.

Species accounts

List of Species

Green catbird

Ailuroedus crassirostris

taxonomy

Ailuroedus crassirostris Paykull, 1815, Nova Hollandia = Sydney, New South Wales, Australia.

other common names

English: Spotted catbird, large-billed cat bird, Australasian catbird; French: Jardinier vert; German: Grünlaubenvogel; Spanish: Capulinero Verde.

physical characteristics

12.2 in (31 cm); female 0.37–0.47 lb (169–211 g), male 0.37–0.64 lb (167–289 g). Brownish head with lime-green upperparts and lighter, streaked coloring underneath; white-tipped wing coverts and tail.

distribution

Subtropical coastal east Australia, from Dawes Range in north to due east of Canberra, at sea level to 3,300 ft (1,000 m) altitude.

habitat

Primarily subtropical rainforest, but also adjacent rainforest edges, eucalyptus forests, gardens, and orchards.

behavior

Perennial socially monogamous pair bonding within an all-purpose territory. Mean year round home range is up to five acres (two ha) but is smaller during the breeding season. Only females build nest, incubate, and brood. Both sexes feed young. Vocal repertoire is of cat-like wailing territorial song and sharp, high-pitched, tick-like contact notes. No mimicry.

feeding ecology and diet

Omnivorous, but predominantly frugivorous; specializes in Ficus figs and other fruits. Also eats flowers, buds, leaves, stems, seeds,

arthropods, and small vertebrates, including birds. Mostly forages in the canopy but also to the ground.

reproductive biology

Breeding mid-September through February/March, egg laying peaks October through December. A large, bulky, open cup nest is mostly built in tree forks, but also found in vine tangles, atop epiphytic ferns, and in tree ferns, at 6.6–60 ft (2–18 m) above ground. Nests are composed of a stick foundation, a cup of large dried leaves and occasional vine stems, a layer of decaying wood and sometimes earthy matter of epiphytic Asplenium ferns, and a fine twiglet/vine tendril egg-cup lining. One to three pale buff, unmarked eggs are laid. Incubation last 23–24 days; nestling period is 21 days.

conservation status

Not threatened. Fairly common and widespread throughout remaining habitat, but rare to absent in rainforest patches of about 6 acres (2.5 ha) and smaller.

significance to humans

Once shot for eating and for sport. Some birds are still killed because they attack cultivated fruit crops.

Tooth-billed bowerbird

Scenopoeetes dentirostris

taxonomy

Scenopoeetes dentirostris Ramsay, 1876, Bellenden Ker Range, Queensland, Australia.

other common names

English: Stagemaker, tooth-billed catbird, leaf turner; French: Jardinier à bec denté; German: Zahnlaubenvogel; Spanish: Capulinero de Pico Dentado.

physical characteristics

10.6 in (27 cm); female 0.35–0.40 lb (157–182 g), male 0.29–0.44 lb (132–199 g). Medium sized, brownish bird with a dark notched bill used to cut leaves for decorating court areas.

distribution

Australian wet tropics, north Queensland; from Big Tableland in the north to Seaview-Paluma Range in south and on Mount Elliot. Mostly occurs at 1,970–2,950 ft (600–900 m) altitude.

habitat

Upland tropical rainforests.

behavior

Courts on average are 200 ft (61 m) apart. Court attendance is during late August through early January, peaks in October through December. Adult males exhibit advertisement vocalization, including much vocal mimicry.

feeding ecology and diet

Primarily herbivorous, eating mostly fruits and leaves but also some flowers and arthropods in the canopy; predominantly folivorous in winter. Fruits and insects, mainly beetles, are fed to nestlings.

reproductive biology

Polygynous, with promiscuous males and exclusively female nest attendance. Breeding occurs September through January; egg laying peaks in November and December. Typically nests in suspended vine tangles 26–88 ft (8–27 m) above ground. Nests are made of a sparse stick foundation, sometimes with orchid stems, and an egg-cup lining of fine twigs. Nest diminutive and sparse. Lays one or two eggs. Incubation and nestling periods are unknown.

conservation status

Not threatened. Common throughout remaining, but protected, habitat.

significance to humans

None known.

Macgregor's bowerbird

Amblyornis macgregoriae

taxonomy

Amblyornis macgregoriae De Vis, 1890, Musgrave River, Papua New Guinea. Seven subspecies.

other common names

English: Macgregor's gardenerbird, gardener bowerbird, crested gardener bird, yellow-crested gardener; French: Jardinier de Macgregor; German: Goldhaubengärtner; Spanish: Capulinero de Macgregor.

physical characteristics

10.2 in (26 cm); female 0.23–0.31 lb (104–140 g), male 0.22–0.32 lb (100–145 g). Brown with lighter head and under-parts; distinctive long red crest.

distribution

Endemic to mountains of eastern and central New Guinea; widespread on central cordillera, west to Weyland Mountains,

Irian Jaya, and on the Adelbert Range, the Huon Peninsula, and Mount Bosavi. Occurs mostly at 5,250–7,540 ft (1,600–2,300 m) altitude. A. m. macgregoriae: W. Kukukuku and Herzog Range east to western Owen Stanley Range; A. m. mayri: Weyland Mountains, Irian Jaya, to eastern Star/western Hindenburg Mountains; Amblyornis m. lecroyae: Mount Bosavi; A. m. kombok: Kubor, Hagen, and Bismarck Ranges, probably west to at least Strickland River or Hindenberg Range and east to Kraetke Range; A. m. amati: Adelbert Mountains; A. m. germanus: Huon Peninsula; A. m. nubicola: Simpson-Dayman massifs, eastern Owen Stanley Range, probably west to Mount Suckling.

habitat

Primary tall mixed montane and Nothofagus rainforest.

behavior

Traditional bower sites are regularly and linearly spaced along forested ridges. The maypole bower consists of a conical tower of sticks built about a sapling or tree fern trunk surrounded at its base by a circular moss mat raised at its circumference into an elevated rim. Bower may be used for 20 or more years. Decorations include insect frass, charcoal, fungus, tree resin, mammal dung, fruits, and leaves. Bowers maintained for nine to ten months annually, with peak display during August through December. Advertisement vocalizations include harsh tearing sounds, growls, thuddings, tappings, whistles, and much vocal mimicry including human-made sounds.

feeding ecology and diet

Primarily frugivorous, taking fruits from numerous trees, shrubs, and vines. Also eats flower parts and insects.

reproductive biology

Polygynous, with promiscuous adult males and exclusively female nest attendance. Breeding season variable across the species range. Typically builds bulky open cup nest in pandanus tree crown 6.6–10 ft (2–3 m) above ground. Nest is composed of a sparse stick foundation, a leafy cup, and an eggcup lining of supple twiglets/rootlets. Lays a single, pale, unmarked, buff egg. One known incubation period was over 17 days. Nestling period unknown.

conservation status

Not threatened. Common and widespread throughout range.

significance to humans

Papuans admire the industry/artistry of males at their bowers. By placing a leaf on a bower mat, men and women used the bower mat clearing behavior of males to indicate to them in which direction they might seek a spouse. Crests of adult males may be worn as personal adornment.

Archbold's bowerbird

Archboldia papuensis

taxonomy

Archboldia papuensis Rand, 1940, Bele River, Snow Mountains, Irian Jaya. Two subspecies

other common names

English: Sandford's bowerbird, Tomba bowerbird, gold-crested black bowerbird; French: Jardinier d'Archbold; German: Arch-boldlaubenvogel; Spanish: Capulinero de Archbold.

physical characteristics

14.2 in (36 cm); female 0.36–0.41 lb (163–185 g), male 0.40–0.42 lb (180–190 g). Brown with distinctive cropped yellow tuft from forehead to back.

distribution

Patchily distributed along the central New Guinea cordillera, mostly at 7,540–9,500 ft (2,300–2,900 m) altitude. A. p. papuensis: Bele River near Lake Habbema, Wissel Lakes, Oranje, Nassau, and Weyland Ranges, Irian Jaya; A. p. sanfordi: Mount Hagen and Giluwe, Tari Gap, and southern Karius Range.

habitat

Frost-prone moss forests.

behavior

The maypole bower consists of a deep terrestrial mat of fern fronds, averaging 10 × 13 ft (3 × 4 m) in size, decorated with discrete piles of snail shells, beetle elytra, tree resin, plumes of

adult male King of Saxony birds of paradise (Pteridophora alberti), and other objects. Perches above the mat are draped with orchid stems and decorated with fruits and other items. Adult males emit diverse advertisement vocalizations that include mimicry.

feeding ecology and diet

Unknown for adults but the nestling diet is mainly of fruit, tree-climbing skinks, beetles, and other arthropods.

reproductive biology

Polygynous, with promiscuous adult males and exclusively female nest attendance. Active nests observed during September through February. Large, bulky, open cup nest is typically built in fork of an isolated sapling 10–23 ft (3–7 m) above ground. Nest is made of a stick foundation, a deep substantial cup of large dried leaves (uppermost ones green), and an egg-cup lining of curved twiglets. The single, unmarked, pale buff, egg is incubated for 26–27 days. The nestling period is 30 days.

conservation status

Considered Near Threatened. Reasonably common and widespread throughout its patchy range.

significance to humans

King of Saxony bird of paradise plumes are highly valued by highland men as personal adornment and are taken from bowers when found.

Golden bowerbird

Prionodura newtoniana

taxonomy

Prionodura newtoniana De Vis, 1883, Tully River Scrubs, North Queensland, Australia.

other common names

English: Newton's bowerbird, Queensland gardener; French: Jardinier de Newton; German: Säulengärtner; Spanish: Capulinero de Newton.

physical characteristics

9.5 in (24 cm); female 0.13–0.21 lb (62–96 g), male 0.13–0.19 lb (62–86 g). Brown head and wings with bright yellow-gold underparts, tail, crest, and nape.

distribution

Australian wet tropics, from Thornton Range and Mount Windsor Tableland in north to Seaview-Paluma Range in south, mostly at 2,300–3,250 ft (700–990 m) altitude.

habitat

Upland tropical rainforests.

behavior

Males build bowers to attract females. Traditional bower sites spatially dispersed throughout suitable topography (flatter terrain and along ridge slopes and ridges), on average 495 ft (151m) apart. Maypole bowers have one or two towers up to 6.6 ft (2 m) tall. Bowers are made of sticks around saplings with a horizontal display perch. Where the perch meets the tower(s), neatly aligned sticks form a platform(s) upon which grayish green lichen, creamy-white seed pods, flowers, and fruits are placed as decorations. Bower structures may remain in use for 20 or more years and traditional sites for much longer. Bowers are attended during August through December/January, peaking in October through December. Adult males emit rattle-like advertisement song and medleys of other calls including mimicry. They follow initial display posturing with an extensive flight and hover display, followed by hiding behind trees while producing vocal mimicry.

feeding ecology and diet

Omnivorous but predominantly frugivorous, eating a variety of fruits including those of many vines. Also eats flowers, buds, and arthropods, particularly beetles. Cicadas are important to the nestling diet. Adults mainly forage in the lower canopy and subcanopy.

reproductive biology

Polygynous, with promiscuous adult males and exclusively female nest attendance. Breeding occurs in late September through January/February. Egg laying peaks in November and December. Typically builds its open cup nest within a roofed tree crevice or crevice-like situation, up to 6.6 ft (2 m) above ground. Nest is composed of a foundation of stout sticks, a substantial bowl structure of dead leaves and leaf skeletons, and an egg-cup lining of fine, supple, springy tendrils. One to three plain whitish eggs are laid. Incubation lasts 21–23 days and the nestling period is 17–20 days.

conservation status

Not threatened. Common and widespread throughout limited remaining but fully protected habitat.

significance to humans

A small number of traditional bowers are of significance to local tourist industries (to the detriment of several resident males disturbed by too frequent human visitations).

Regent bowerbird

Sericulus chrysocephalus

taxonomy

Sericulus chrysocephalus Lewin, 1808, Patterson's River = Hunter River, New South Wales, Australia.

other common names

English: Regent bird, Australian regent bowerbird, king honey sucker, golden regent; French: Jardinier prince-régent; German: Gelbnacken-Laubenvogel; Spanish: Capulinero Governador.

physical characteristics

9.8 in (25 cm); female 0.20–0.30 lb (91–138 g), male 0.17–0.24 lb (76–110 g). Black with bright yellow flight feathers and area from forehead to shoulder; orange-red band from forehead to nape. Eyes are bright yellow.

distribution

Subtropical coastal zone of central eastern Australia from immediately north of Sydney to the Connors and Clarke Ranges, Eungella Plateau, inland of Mackay, Queensland, with a gap in distribution around the Fitzroy River valley inland of Rock-hampton. From sea level to 2,950 ft (900 m), but altitude varies across the range.

habitat

Subtropical rainforest, adjacent woodland, and, in winter, more open habitats, including cultivated country and urban gardens.

behavior

Males build bowers to attract females. The sparse and small avenue bower is well concealed beneath low dense vines/foliage. Traditional bower sites are dispersed through appropriate ridge top habitat. Bowers discovered by rivals are destroyed, if not by a rival then by the owner. Another bower is then built at a nearby location. Bower structures last an average of 10 days or less. Decorations include green leaves, flowers, fruits, snail shells, and cicada ectoskeletons. Seasonal bower attendance mostly September through January on Sarabah Range but from July through August elsewhere. Adult males vocalize by producing harsh grating sounds; when courting they emit a soft complex subsong.

feeding ecology and diet

Omnivorous but predominantly frugivorous. Also eats flowers, nectar, and animals. Females dominate males at feeding trees.

reproductive biology

Polygynous, with promiscuous adult males and exclusively female nest attendance. Breeding occurs September through February. Egg laying peaks in November and December. Typically builds relatively frail open cup nest among clumps of vines or mistletoe 6.6–102 ft (2–31 m) above ground. Nests are made of a frail shallow saucer of loose sticks and an egg-cup lining of finer twigs with a few leaves. One to three colored and vermiculated eggs are laid. Incubation in captivity lasted 17–21 days and nestling period at one nest was 17 days.

conservation status

Not threatened. Common and widespread throughout limited remaining but mostly protected habitat. In some areas numbers are reported as greatly reduced to uncommon because of habitat destruction and degradation.

significance to humans

Adult males were once systematically hunted for mounting as decorative novelties commonly included in cabinets of stuffed birds. They are also a popular cage bird, both within and outside Australia. Birds may be pests to cultivated fruit crops.

Satin bowerbird

Ptilonorhynchus violaceus

taxonomy

Ptilonorhynchus violaceus Vieillot, 1816, Nouvelle Hollande = Sydney, New South Wales, Australia. Two subspecies.

other common names

English: Satin bird, satin grackle, purple satin; French: Jardinier satiné; German: Seidenlaubenvogel; Spanish: Capulinero Satinado.

physical characteristics

13 in (33 cm); female 0.38–0.57 lb (170–258 g), male 0.38–0.64 lb (173–290 g). Iridescent black plumage with light legs and

bill. Female slightly smaller with green, gray-green, brown, and buff coloring.

distribution

Eastern and southeastern Australia. P. v. violaceus: coastal zone of southeast Australia from Otway Range, immediately east of Melbourne, east and North to Dawes Range just south of the Fitzroy River at Rockhampton; from sea level to 3,600 ft (1,100 m). P. v. minor: Australian wet tropics, from Seaview-Paluma Range north to Mount Amos near Cooktown, typically over 1,970 ft (600 m) altitude.

habitat

Rainforests, with a strong preference for their edges, and adjacent woodlands with dense sapling understory. Frequents more open habitats when winter flocking, then frequents pastures and urban/suburban areas.

behavior

Males build bowers to attract females. Avenue bowers are fairly evenly and linearly dispersed at an average of about 990 ft (300 m) apart along rainforest edges, often further apart in rainforest patches and woodlands. Mostly bluish and greenish yellow items are used as decorations, including flowers, fruits, parrot feathers, snake skin, snail shells, and numerous human-made objects. Seasonal bower attendance commences in late August/September and peaks during October through December. Adult males emit advertisement vocalizations with a clearly-whistled quoo-eeeew, various harsh notes, and vocal mimicry.

feeding ecology and diet

Omnivorous but predominantly frugivorous. Also eats flowers, leaves, nectar, seeds, and animals including cicadas, beetles, and other arthropods. Forages mostly in the canopy but winter flocks forage on the ground for pasture leaves and herbs.

reproductive biology

Polygynous, with promiscuous males and exclusively female nest attendance. Breeding occurs August/September through February. Egg laying peaks in November and December. Typically builds open cup nest in trees or bushes, but also in vine tangles and mistletoe, at 6.6–131 ft (2–40 m) above ground. Nests are composed of a shallow saucer of sticks and twigs and an egg-cup lining of green and dry leaves (mostly of Eucalyptus and Acacia). One to three colored and blotched, rarely vermiculated, eggs are laid. Incubation is 21–22 days and nestling period is 17–21 days.

conservation status

Not threatened. A common to reasonably abundant bird in remaining habitat but has lost habitat because of human land use.

significance to humans

Ornithological and popular literature contains numerous stories of males removing jewelry, keys, and other items from homes, vehicles, camps, etc. to decorate bowers

Spotted bowerbird

Chlamydera maculata

taxonomy

Chlamydera maculata Gould, 1837, New Holland = Liverpool Plains, Australia, New South Wales, Australia.

other common names

English: Large-frilled bowerbird, cabbage bird; French: Jardinier maculé; German: Fleckenlaubenvogel; Spanish: Capulinero Moteado.

physical characteristics

11.4 in (29 cm); female 0.27–0.36 lb (124–162 g), male 0.28–0.33 lb (125–150 g). Mottled brown with lilac bar across the back of the neck.

distribution

Interior of Queensland south of 20 degrees South, except the extreme west and southwest, and interior of west and central New South Wales, except the extreme western border country. Extends a small way into the northwest corner of Victoria and just into South Australia along the Murray River system. Occurs from sea level to about 1,640 ft (500 m).

habitat

Brigalow and open eucalyptus woodlands, with a preference for riverine woodland.

behavior

Grassy avenue bowers are built beneath low bushes or shrubs, 3,300–6,600 ft (1,000–2,000 m) apart. Decorations (to 1,000 or more) include berries, seed pods, pebbles, bones, snail shells, and glass. Adult males emit infrequent, loud, far-carrying advertisement vocalizations of harsh churrings and other notes including vocal mimicry.

feeding ecology and diet

Omnivorous. Eats fruits, flowers, leaves, seeds, and arthropods. Grasshoppers are important to the nestling diet.

reproductive biology

Polygynous, with promiscuous males and exclusively female nest attendance. Breeding occurs during July through March. Egg laying peaks in October through February. Typically places sparse open cup nest in trees and bushes at 10–40 ft (3–12 m) above ground. Nests are made of a loose bulky foundation of dead twigs and sticks and an egg-cup of fine twiglets, sometimes with dried grass stalks. Incubation period is unknown. Nestling period at one nest was 21 days.

conservation status

Not threatened, but numbers have historically declined in some areas because of illegal shooting and poisoning, predation by domestic and feral cats and foxes, and widespread clearing and/or modification/fragmentation of habitat. Populations are officially considered Endangered within state of Victoria.

significance to humans

Commonly kept in aviculture, where birds thrive. Bird known to steal items from homes, camps, and vehicles for bower decorations. Birds are killed as pests to gardens and orchards.

Resources

Books

Frith, C.B., and D. W. Frith. The Bowerbirds: Ptilonorhynchidae. Oxford: Oxford University Press, 2002.

Gilliard, E.T. Birds of Paradise and Bower Birds. London: Weidenfeld and Nicolson, 1969.

Marshall, A.J. Bower-birds, Their Displays and Breeding Cycles— A Preliminary Statement. Oxford: Oxford University Press, 1954.

Schodde, R., and I. J. Mason. The Directory of Australian Birds, Passerines. Melbourne: CSIRO, 1999.

Periodicals

Borgia, G. "Why Do Bowerbirds Build Bowers?" American Scientist 83 (1995): 541–547.

Dwyer, P., M. Minnegal, and J. Thomson. "Odds and Ends, Bower Birds as Taphonomic Agents." Australian Archaeology 21 (1985): 1–10.

Frith, C.B., and D.W. Frith. "Biometrics of the Bowerbirds (Aves: Ptilonorhynchidae): with Observations on Species Limits, Sexual Dimorphism, Intraspecific Variation and Vernacular Nomenclature." Memoirs of the Queensland Museum 24 (2001): 512–542.

Madden, J. "Sex, Bowers and Brains." Proceedings of the Royal Society of London B 268 (2001): 833–838.

Organizations

Birds Australia. 415 Riversdale Road, Hawthorn East, Victoria 3123 Australia. Phone: +61 3 9882 2622. Fax: +61 3 98822677. E-mail: [email protected] Web site: <http://www.birdsaustralia.com.au>

Clifford B. Frith, PhD

Dawn W. Frith, PhD