Struthidea cinerea

Geographic Range

Apostlebirds ( Struthidea cinerea ) are found in eastern Australia, on the western side of the Great Dividing Range. They occur only on the mainland and are non-migratory.

• Biogeographic Regions
• australian australian
  • native native

Habitat

Preferred apostlebird habitat is generally grassland and open eucalyptus woodlands. They require a nearby water source, such as a stream, in order to obtain mud for nest building.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland
• forest forest
• scrub forest scrub forest

Physical Description

Apostlebirds are 29 to 47 cm in length, and weigh 110 to 130 g. Their plumage is soft and dark gray with paler gray streaks, their wings are brown, and their tails are black. They have stout bills. Males and females are sexually monomorphic in plumage and size. Iris color varies with age; fledglings have brown eyes, yearlings have gray eyes, and adults (at least 2 years old) have gray eyes with a thin yellow outer ring. This ring becomes more apparent as the birds age.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Apostlebirds are cooperative breeders. They form familial social groups of up to 20 members, consisting of a dominant male, several females, and juveniles from previous seasons. These immature members stay to help with parental duties. During the breeding season, the groups occupy distinct, well-defended territories.

Before breeding, apostlebirds engage in a characteristic display. Birds at the nest become excited and give a call. The displaying bird raises its head and neck feathers and bobs up and down in time with the calls. It also fans its tail and raises it up and down.

• Mating System
• polygynous polygynous
• cooperative breeder cooperative breeder

The breeding season is from August to early January. All group members help in parental duties, i.e., building the nest, incubating and brooding the nestlings, and feeding the young. The nest is a cup, about 14 cm in diameter, made of mud and built on a horizontal limb up to 40 feet above the ground. If mud is not available, the birds may use animal dung, including that of emus . If a nest is still in good condition after a previous breeding season, it is sometimes reused.

A group will sequentially raise up to two successful broods in a single season. Usually only one female will lay in a given nest, but sometimes two females may do so. Two to eight eggs are laid, depending on how many females are laying in the nest. The eggs are a pale bluish white color with black or gray splotches. Incubation takes 18 to 19 days, and the nestling period is 18 to 29 days. Usually only about 4 nestlings survive to fledge.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

All members of the social group help with parental duties. The young are fed both while in the nest and for several months after they fledge. Young may also remain with their family group for some time.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-independence
  • provisioning
    • female
  • protecting
    • male
    • female
• post-independence association with parents

Lifespan/Longevity

There is little available information regarding the lifespan of wild or captive apostlebirds.

Behavior

Apostlebirds are social birds, forming groups of 8 to 18 individuals. Most groups consist of 4 to 11 individuals. They spend most of their time on the ground, where they walk with a strutting gait. If disturbed, group members will fly into the branches of a nearby tree and call harshly.

Apostlebirds are known to bathe in water during the summer when they go to drink. They also engage in anting to control ectoparasites such as lice, and they commonly eat the ants when finished. Another method of pest control is allopreening, several birds will often sit together and preen each other.

• Key Behaviors
• arboreal arboreal
• terricolous
• flies
• diurnal diurnal
• motile motile
• sedentary sedentary
• territorial territorial
• social social

Home Range

Apostlebird home ranges have not been reported.

Communication and Perception

Apostlebirds give contact calls that consist of piping whistles. Their alarm call is mainly harsh screeches and chattering, sounding like a scratchy 'ch-kew, ch-kew' with a nasal 'git-out.'

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Apostlebirds forage on the ground, eating mainly insects and seeds. The insects they consume include grasshoppers, weevils, shield-bugs, and ants. They are opportunistic, eating insects during the summer and seeds during the winter. They will even catch and eat house mice ( Mus musculus ) if they have the opportunity. They steady their food by standing on it.

During the non-breeding season, aggregations of up to 50 birds gather at a common food source. While they do not behave aggressively toward each other at this time, they do not form a cohesive flock, and fly off in separate groups when disturbed.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
• herbivore herbivore
  • granivore granivore

• Animal Foods
• mammals
• insects
• terrestrial non-insect arthropods

• Plant Foods
• seeds, grains, and nuts

Predation

Apostlebirds have a harsh, screeching alarm call that they use when they are disturbed. They fly into the nearest tree and protest noisily. Their nests have been known to fail due to predation by brown goshawks ( Accipiter fasciatus ) and grey butcherbirds ( Cracticus torquatus ). Newly hatched young can also be overtaken by meat ants ( Iridomyrmex purpureus ).

Ecosystem Roles

There is little available information about the ecosystem roles of apostlebirds. They act as predators and are prey for their predators.

Economic Importance for Humans: Positive

Little is known about benefits apostlebirds provide to humans.

Economic Importance for Humans: Negative

Due to their habit of digging in soil and leaf litter as they forage, apostlebirds may be a nuisance to some humans, such as gardeners. Otherwise, there are no known adverse effects of apostlebirds on humans.

• Negative Impacts
• crop pest

Conservation Status

Apostlebirds are considered a species of least concern by the IUCN Red List of Threatened Species.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Laura Mateskon (author), Michigan State University, Pamela Rasmussen (editor, instructor), Michigan State University.

References

Blakers, M., S. Davies, P. Reilly. 1984. The Atlas of Australian Birds . Victoria: Melbourne University Press.

Chapman, G. 1998. The Social Life of the Apostlebird Struthidea cinerea. Emu , 98: 178-183.

Hill, R. 1967. Australian Birds . Melbourne, Australia: Thomas Nelson (Australia) Ltd..

Simpson, K., N. Day. 1984. The Birds of Australia . Dover, NH: Tanager Books.

Woxvold, I. 2004. Breeding ecology and group dynamics of the apostlebird. Australian Journal of Zoology , 52: 561-581.

1975. Every Australian Bird Illustrated . London: Hale.

Australian Museum. 2006. "Apostlebird" (On-line). Birds in Backyards. Accessed December 05, 2006 at http://birdsinbackyards.net/finder/display.cfm?id=133 .

1967. Magpie-Larks and Australian Mudnesters. Pp. 493 in Firefly Encycopledia of Birds , Vol. 1, 1 Edition. Toronto: Firefly Books Ltd..