PSEUDO BABBLERS: Pomatostomidae

PHYSICAL CHARACTERISTICS

Pseudo babblers are medium-sized birds, measuring 7 to 10.5 inches (18 to 27 centimeters) long, and weighing 1.6 to 3.2 ounces (45 to 90 grams). They have short wings, long fan-shaped tails, and thin, pointed bills that are ideal for probing and digging into the ground or bark. Their long, powerful legs and dark, strong feet allow them to hop for long periods along the forest floor and among low tree branches. Their bodies are mainly a solid rust color or a dull brown highlighted with white brows, throat, and tail tip. There is no difference in color between males and females or between young and mature birds. The only change that comes with adulthood is a longer bill. The rufous babbler and the gray-crowned babbler, however, change the color of their eyes on adulthood, from the normally brown eyes of this family of birds to pale cream.

GEOGRAPHIC RANGE

Australia and lowland New Guinea.

HABITAT

Pseudo babblers of New Guinea live in regions up to 1,500 feet (500 meters). Members of this family can also be found in the western Papuan Islands and throughout Australia. They avoid the desert regions of the central and northwest and the southeastern and southwestern seacoasts. Mostly, pseudo babblers forage under eucalyptus (yoo-kah-LIP-tus) trees and in clearings among acacia (uh-KAY-shah) trees. In New Guinea, they occupy rainforests. Where the foraging territories overlap, different species of pseudo babblers do not divide the resources between groups; they openly compete for the same foods in the same areas.

DIET

This family of birds eats mainly insects and spiders but sometimes will eat seeds, buds, and fruit, and even small reptiles.

BEHAVIOR AND REPRODUCTION

Social birds, pseudo babblers live and forage in communal groups of twelve or more birds. These groups consist of one primary breeding pair, their offspring, and even their siblings. They will roost, feed, rest, and preen together. They constantly call out to each other as they move about the forest floor as if to keep in hearing range of one another. At night, they all cluster together in large, sturdy dormitory nests to sleep.

These birds forage in permanent territories of approximately 124 acres (50 hectares), using their long bills to shift through the litter on the forest floor. Sometimes, they will dig into the ground or poke into the trunks and branches of trees. If they find a large insect or small reptile, they will share the food with the group.

Depending on the location and the species, breeding occurs in the spring and early summer of the Southern Hemisphere. In New Guinea, however, breeding occurs whenever the conditions within the region can support the young. The primary breeding pair builds the dome-shaped nest, made from twigs and plant fibers and lined with animal hair and finer plant materials. These nests are constructed in the upper branches of shrubs and trees up to 6.6 to 16.2 feet (2 to 8 meters) above the ground. Rufous babblers in New Guinea anchor their nests on the tips of palm fronds.

COMMUNAL BREEDING

The survival of the gray-crowned babbler depends on the number of helper birds in each social group. These birds are critical to the rearing of the young and the defense of the group's territory. Helpers in these social groups usually are the siblings of the primary mating pair or the pair's own grown offspring. Unlike bees, which also have a highly developed social structure, helper birds are able to breed and do so when the primary pair has died and a new primary pair takes over leadership of the group.

The primary female lays two to five pale gray eggs that are covered with dark lines. While she incubates, or sits on the eggs until they hatch, for sixteen to twenty-three days, she is fed by all of the members of the social group. The group will also help feed the young hatchlings for twenty to twenty-one days.

PSEUDO BABBLERS AND PEOPLE

Pseudo babblers have no known significance to humans.

CONSERVATION STATUS

Pseudo babblers in some areas of Australia are threatened, or at a risk of extinction, or dying out. They have disappeared from some regions altogether. This is a result of habitat loss due to clearing land for agriculture and the introduction of invasive plants and livestock grazing.

GRAY-CROWNED BABBLER (Pomatostomus temporalis): SPECIES ACCOUNT

Physical characteristics: The gray-crowned babbler is also called the chatterbox, the happy family, the red-breasted cackler, and the happy jack. It is the largest of the pseudo babblers, measuring 9.5 to 10.5 inches (24 to 27 centimeters) long and weighing 2.2 to 3.2 ounces (65 to 90 grams). This bird has a dull brown body with the characteristic pseudo babbler white markings. It displays a reddish patch on its outer wings when it flies, and its undersides range from dull brown to deep russet brown. It has a brown bill, black feet, and pale cream-colored eyes. The back and center crowns of the head are gray, giving the bird one of its names.

Geographic range: The gray-crowned babbler can be found mainly in northern and eastern Australia, and is also located in a small region in southern New Guinea.

Habitat: The gray-crowned babbler lives in trees of moderate height and sometimes in shrubs. It prefers eucalyptus, cypress, and paper-bark trees. Since much of its habitat has been cleared for agriculture, this species has been limited to clusters of trees along roadways in their territories. They stay within these narrow bands of trees because they are not strong fliers and are reluctant to fly over open land.

Diet: This species eats mainly insects.

Behavior and reproduction: The gray-crowned babbler is not afraid of heights. It will forage as far as 66 feet (20 meters) up a tree, turning over leaves and poking into crevices in bark. In drier regions where trees do not grow as tall, this bird will also sift through the litter on the forest floor and even scratch in the dirt, looking for food. Sometimes, it will try to catch flying termites on the wing.

This species is rather social, foraging in groups of twelve to fifteen over 25 to 37 acres (10 to 15 hectares) and sleeping together in dormitory nests. Their loud "yahoo yahoo" calls mark territory but also warn of predators and act as a means of staying in touch with all members of the social group.

These birds find mates not only in the Australian spring and summer, but also in the fall. Two to four eggs are laid in huge, messy, dome-shaped nests made from twigs that are built in the forks of branches of shrubs or trees 9.8 to 32.8 feet (3 to 10 meters) high. The female incubates the eggs for eighteen to twenty-three days. The young are fed in the nest for twenty to twenty-two days. If there are several breeding pairs within the group, they will use the same nest and share incubation duties. Sometimes, there are as many as ten or more eggs in these communal nests.

Gray-crowned babblers and people: There is no known significance to humans.

Conservation status: The gray-crowned babbler has seriously reduced its numbers and is already extinct in South Australia and in Victoria. Its territory has been reduced because of clearing nearly 90 percent of their habitat for agricultural use and to build roads. Overuse of the land because of irrigation practices has raised the ground water level and caused serious changes in the bird's habitat. In addition, the introduction of invasive weeds and grazing livestock has led to continued destruction of the native vegetation. Complicating this scenario are competitors such as noisy miners that have further stressed the food supply and species including the Australian raven that are competing for nesting sites. Because of these factors that reduce available food sources and restrict nesting to certain areas, population numbers for this species have dropped dramatically since the 1960s. It is, therefore, listed as endangered, or at high risk of becoming extinct, by the Australian government, though it is not listed by the World Conservation Union (IUCN). ∎

FOR MORE INFORMATION

Books:

Higgins, P. J., and J. M. Peter, eds. Handbook of Australian, New Zealand and Antarctic Birds. Vol. 6, 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, 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.