Family RALLIDAE Rafinesque, 1815

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Introduction

With 151 species in 38 genera, the homogeneous rallids, apart from Himantornis, constitute a large cosmopolitan family of terrestrial birds; 23 of which have an Australian distribution. Although absent from Antarctica the family has spread widely on the other continents, principally in sub-temperate and tropical areas, and even colonising many oceanic islands, including sub-Antarctic islands. Their sizes range from small to medium; among them are groups such as the crakes, gallinules and coots. A major character of many of the wetland-dwelling species is their thin, laterally compressed body.

As with many families, many of the males have a tendency to be slightly larger than the females but they do not exhibit much sexual dimorphism in size or plumage characteristics. Numerous island taxa are flightless, having reduced wings and breast muscles; this morphology has evolved rapidly on islands where predators are absent. Despite their short and rounded wings and appearance of feeble flight, rallids do conduct nocturnal movements over great distances. During the day, flight about a localised area is effected with the feet dangling and culminates with an awkward drop into cover. Their preference is to run from potential disturbance; this habit is extreme during moulting as many species lose their ability to fly through loss of primaries.

Most rallids are cryptic skulkers with either dull or sombre plumage (e.g. Fulica spp.) or streaked and barred (e.g. Gallirallus spp.). As such, several are infrequently noted except through vocalisations. Several of those having sombre feathering have evolved a colourful frontal shield extending across the forehead from the maxilla (e.g. Gallinula spp., Fulica spp.). Many form loose congregations (e.g. Porzana spp.) whereas others collect in large gregarious flocks (e.g. Tribonyx spp.). In most species the undertail feathers are white and are used by the birds for either display as an alarm. The short tail is almost constantly flicked in the larger cursorial species while in the smaller species it is often degenerate and ragged.

The large legs and feet of rallids may be stout and heavy in the larger terrestrial species; walking on floating vegetation is assisted by the elongate anisodactyl toes. Most of the family have a skulking action while walking; several groups are capable of swimming (Fulica, Gallinula, Porphyrio). Within the several species of Fulica modifications of the pelvis and the well-developed toe lobes have adapted them for swimming and diving. The rallid bill is the most variable feature: some are longer than the head (Rallus longirostris); massive (Porphyrio mantelli); short (Porzana pusilla); or slender (Lewinia pectoralis).

A generalised habitat of the rallids would include most wetlands (swamps, marshes, lagoons, lakes and rivers), the birds roosting in the thick vegetation bordering the water or growing within its boundaries. They also frequent dense forests such as are found in New Guinea. Others (e.g. Tribonyx ventralis, P. fluminea) follow permanent or semi-permanent wetlands in the Australian arid regions or thick grasslands inundated by recent rains (e.g. Gallirallus philippensis). All species are omnivorous: the smaller rallids feed in rank vegetation taking invertebrates, crustaceans and plants; the larger taxa have a similar diet but also include fish, amphibians, eggs and young of birds and carrion. Both Fulica spp. and Gallinula spp. graze and dive to obtain wetland plants. Many are noted to wash their prey before consuming it.

Vocalisations are mostly heard at dawn and dusk with an increase in consistency prior to and during the breeding periods. These calls consist of a variety of raucous cackling, grunting and associated clucking. While many species breed alone some males maintain two active nests, caring for both females and their offspring (e.g. G. tenebrosa). Displays at the nest site include swimming while flicking and displaying their undertail coverts; these courtships are short lived and simple and are initiated by either sex. The birds become protective of the nest site, discouraging the presence of others of their species or any other interloper; this includes use of their feet in a defensive manner.

Nest construction is performed by both sexes collecting reedy growth adjacent to the chosen site; the nests are an open cup. This site may be on the ground or within reed beds or on mats of floating water plants; the only divergence from this is by Africa’s Himantornis haematopus which reportedly constructs an arboreal nest. Both adults share in incubation duties. Egg clutches vary in number from two to 16, and eggs vary in shape from short-oval to oval; they also vary in their base colour from pure white to dark tan, splotched and speckled by darker tans. On hatching, the young are both precocial and nidifugous, clothed in black down and may have coloured head marks (apart from the cryptic Himantornis young which are mottled brown). Heads of nestling Fulica are covered by orange or reddish filaments.

Although able to leave the nest shortly after hatching, the young birds often return to be brooded on the nest. They are fed by parents and/or young of previous nesting successes who assist in raising subsequent broods (e.g. G. tenebrosa). Family groups may remain together until the following breeding period commences at which stage the resident adults chase off their young by loud calls and fights.

Excluded Taxa

Vagrant Species

CAVS:0899
RALLIDAE: Crex crex (Linnaeus, 1758) [Corncrake] — Anonymous 1969. An Index of Australian Bird Names. Division of WIldlife Research Technical Paper. Canberra : CSIRO Vol. No. 20 pp. 93. [18]; Christidis, L. & Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. Melbourne : CSIRO Publishing 288 pp. [22, 121, 126]

CAVS:0711
RALLIDAE: Gallicrex cinerea (Gmelin, 1789) [Watercock; vagrant to Christmas and Cocos (Keeling) Islands] — Christidis, L. & Boles, W.E. 1994. The Taxonomy and Species of Birds of Australia and its Territories. Monograph 2. Melbourne : Royal Australasian Ornithologists Union iv 112 pp.; Christidis, L. & Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. Melbourne : CSIRO Publishing 288 pp. [22, 124, 125, 126]

CAVS:8090
RALLIDAE: Gallinula chloropus (Linnaeus, 1758) [Common Moorhen] — Christidis, L. & Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. Melbourne : CSIRO Publishing 288 pp. [125]

CAVS:0900
RALLIDAE: Rallina (Rallina) fasciata (Raffles, 1822) [Red-legged Crake; one Australian record (specimen) from Broome, WA (16 July 1958)] — Christidis, L. & Boles, W.E. 1994. The Taxonomy and Species of Birds of Australia and its Territories. Monograph 2. Melbourne : Royal Australasian Ornithologists Union iv 112 pp.; Christidis, L. & Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. Melbourne : CSIRO Publishing 288 pp. [22, 120, 126]; Simpson, K. & Day, N. 2010. Field Guide to the Birds of Australia. Camberwell, Victoria : Penguin Group (Australia) 8, pp. 381. [289]

CAVS:8089
RALLIDAE: Zapornia fusca fusca (Linnaeus, 1766) [Eastern Ruddy-breasted Crake]

CAVS:8088
RALLIDAE: Zapornia fusca (Linnaeus, 1766) [Ruddy-breasted Crake]

General References

Campbell, B. & Lack, E. (eds) 1985. A Dictionary of Birds. Calton : T. & A.D. Poyser xxx 670 pp.

Christidis, L. & Boles, W.E. 2008. Systematics and Taxonomy of Australian Birds. Melbourne : CSIRO Publishing 288 pp.

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