LOGRUNNERS AND CHOWCHILLAS: Orthonychidae

PHYSICAL CHARACTERISTICS

The three species of this family of Passeriformes, or perching birds, are very similar in appearance. The largest, the chowchilla, is about 12 inches (30 centimeters) long. The two species of logrunners are only 7.3 to 8.4 inches (18.5 to 21 centimeters) long. They are stocky birds, with powerful legs and claws. Their specialized tails bear sharp spines on the stiff shafts of all ten tail feathers. This trait led this family of birds to also be called spine-tailed logrunners.

Male logrunners and chowchillas have white breasts, and females have reddish orange breasts. Chowchillas have unmarked black and white feathers. Logrunners, however, have patterns of brown, black, gray, white, and dull red.

GEOGRAPHIC RANGE

Logrunners and chowchillas are found only in Australia and New Guinea. The southern logrunner is restricted to the eastern coastal forests of Australia. The chowchilla is found in northeastern Australia in the Atherton Tableland region above 1,475 feet (450 meters). The New Guinea logrunner occupies territory in the central highlands of New Guinea from 6,500 to 9,300 feet (1,980 to 2,840 meters). Some subspecies of the New Guinea logrunner live in regions as far up as 11,300 feet (3,450 meters) and in lower areas near 3,900 feet (1,200 meters).

HABITAT

Logrunners and chowchillas live on the litter-strewn floor of dense rainforests and wet sclerophyll (SKLARE-uh-fill) forests. Sclerophyll forests have plants with hard leaves that have adapted, changed, to low levels of phosphorous, a chemical that encourages plant growth. Logrunners and chowchillas will move into nearby vegetation if it is dense enough. These adjacent territories may include non-native plants have been introduced into the wild.

DIET

Logrunners and chowchillas eat adult insects, larvae (LAR-vee), the newly hatched form of insects, and worms. Sometimes they also forage for berries.

BEHAVIOR AND REPRODUCTION

Logrunners and chowchillas never leave their permanent ranges of 1.7 to 9.8 acres (0.7 to 4 hectares), though they will defend a much larger territory. They live with a mate or in small groups of two to five birds.

Logrunners and chowchillas have different mating patterns. Logrunners begin nesting in the winter months as early as April and last until November. The chowchilla nests anytime, but July through December is most common. Females of all three species build dome-shaped nests made of twigs, which are topped with dry leaves and moss, and include a roof overhang that keeps the interior nest dry during rainstorms. Chowchilla nests are larger to accommodate their bigger size.

Female southern logrunners lay two white eggs. Chowchillas and the New Guinea logrunner lay only one, although only 75 percent of the eggs hatch. Eggs hatch after twenty-one to twenty-five days and chicks remain in the nest for sixteen to eighteen days for the northern logrunner and twenty-two to twenty-seven days for the chowchilla. Females incubate, or sit on the eggs until they hatch. Males bring food to the female, but only she feeds the young. More than one chowchilla male will bring food to the female for the hatchlings. After the fledglings, birds that have grown the feathers needed for flight, leave the nest, they are still fed by both parents.

Chowchillas and logrunners have loud calls that can be heard at dawn before the birds begin foraging, searching for food, and at dusk when they are settling down for the night. If they encounter other birds, they will call out as if to remind others of their territory boundaries.

These birds are shy and will shriek if startled, but have been known to ignore humans when they feed, walking right over a person's foot as they forage.

LOGRUNNERS, CHOWCHILLAS, AND PEOPLE

Because these birds are relatively shy and their habitats are restricted, they are unknown to most people except one native group. The Dyirbal Aboriginal people named the chowchilla after its call, which is: "chow chowchilla chowry chook chook."

SCLEROPHYLL FORESTS

Sclerophyll (SKLARE-uh-fill) forests, where logrunners live, are unique to Australia. These forests evolved, changed, in response to low levels of phosphorous, a chemical that encourages plant growth. Sclerophyll plants have hard leaves that contain lignin, a substance that prevents them from wilting. Dry sclerophyll forests have eucalyptus trees that are 32.8 to 98.4 feet (10 to 30 meters) tall with smaller sclerophyllic plants underneath. Eucalyptus (yoo-kah-LIP-tus) in wet forests are taller, over 98.4 feet (30 meters), and contain plants with softer leaves such as tree ferns.

CONSERVATION STATUS

Southern logrunners, although not threatened with extinction, dying out, are decreasing in population due to the clearing of rainforest for pasture and farmland. They are adapting by moving into places where exotic plants have been introduced and have spread into zones between cleared land and the remains of rainforests. Chowchillas, on the other hand, have not been affected by the loss of sections of their habitat through deforestation, the cutting down of trees. New Guinea logrunners are considered rare but this is most likely due to their shy nature and the remoteness of their territory.

SOUTHERN LOGRUNNER (Orthonyx temminckii): SPECIES ACCOUNT

Physical characteristics: Southern logrunners, also known as spine-tailed logrunners, are 7.3 to 8.3 inches (18.5 to 21 centimeters) long. Males weigh 2.08 to 2.4 ounces (58 to 70 grams), and females weigh 1.6 to 2.08 ounces (46 to 58 grams). This species has tan and grey feathers with a black stripe on its wings. The female has an orange throat, while the throat of the male is white.

Geographic range: These birds live in a narrow strip forest on the eastern coast of Australia from New South Wales in the north to Queensland in the south.

Habitat: Southern logrunners thrive in the heavy vegetation on the rainforest or wet sclerophyll forest floor. They will range into nearby underbrush if it is sufficiently dense.

Diet: Southern logrunners eat insects, worms, and other invertebrates, animals without backbones, that they find in the soil.

Behavior and reproduction: Southern logrunners use their tails to help them find food. Spreading their tails, they anchor the sharp tips into the ground.

This allows them to rake their feet through the litter on the forest floor, and scratch the ground to uncover larvae and insects. They can pivot on their tails, clearing an 8-inch (20-centimeter) circle. Yellow-throated scrubwrens and eastern whipbirds often follow behind logrunners and chowchillas and pick up insects and grubs the other birds ignored.

Southern logrunners stay within their territory throughout the year. They mate for life and will form small family groupings within their territory. The bird usually breeds from May to August, but have been observed mating as early as April and as late as October, producing one or two broods, groups of offspring hatched at the same time.

Only the female builds the nest, which is a dome-shaped structure, made of sticks and grasses, built against a tree trunk or bush low to the ground. The entrance is placed on the side and a flap of moss covers the entryway, protecting the interior from rain.

Only two white eggs are laid by the female. The female incubates the eggs for twenty-one to twenty-five days. When hatched, the young birds remain in the nest for sixteen to eighteen days, fed by their parents.

Although shy, they will ignore humans. But when startled or in danger, their piercing "keek" call can be heard for some distance. Their normal song is an equally loud series of "weet" sounds.

Southern logrunners and people: There is no known significance between southern logrunners and people.

Conservation status: Southern logrunners are not threatened with extinction. Their population in the northern part of their range is large enough for the species to be considered common. Their numbers in the south are decreasing, and they are quite rare in the southernmost part of their range, due to the cutting down of the southern rainforests. Southern logrunners survive in pockets of rainforest in the south by moving into areas where exotic plants like black-berry bushes and lantana have been planted and quickly moved into cleared land. ∎

FOR MORE INFORMATION

Books:

Higgins, P. J., and J. M. Peter, eds. Handbook of Australian New Zealand and Antarctic Birds: Pardalotes to Shrike-thrushes. Melbourne: Oxford University Press, 2003.

Perrins, Christopher. Firefly Encyclopedia of Birds. Richmond Hill, Canada: Firefly Books, 2003.

Robbins, Michael. Birds: Fandex Family Field Guides. New York: Workman Publishing Company, 1998.

Schodde, R. Directory of Australian Birds: Passerines. Collingwood, Australia: CSIRO Publishing, 1999.

Simpson, K., and N. Day. A Field Guide to the Birds of Australia. Ringwood, Australia: Penguin Books Australia Ltd., 1996.

Weidensaul, Scott. Birds: National Audubon Society First Field Guides. New York: Scholastic Trade, 1998.