Australian Brush-turkey (Alectura lathami) Fact Sheet: Reproduction & Development

Attracting a mate

• Adult males each build and defend 1-2 incubation mounds to attract females (Göth 2007a)
  • Carefully select the mound site (Jones and Göth 2008)
  • Use large feet to move 2-4 t (4,400-8,800 lb) of material into a pile (Jones 1988b)
  • If a male builds two mounds, both must be tended and protected (Jones 1990b; Jones and Göth 2008)
    • Usually located close together
    • Beneficial in receiving more eggs, or if the first mound is damaged or taken by another male
  • See Incubation Mounds
• After construction, males arrive at their mound early in the day and wait for females (Jones et al. 1995)
• Compete over possession of incubation mounds (Jones 1990b)
• Males produce boom vocalizations (Jones et al. 1995)
  • These might advertise their location and status
• Females begin visiting the mounds about one month after construction begins (Jones and Göth 2008)
  • Allows sufficient time for decomposition, which heats the mound’s interior in preparation for the eggs
• Males attempt to attract females to their nesting mounds (Wells et al. 2014)
  • Aggression and harassment of females not uncommon
    • Coercion tactics infrequently lead to mating success

Mating system

• Males and females do not form pair bonds (Birks 1997; Birks 1999)
  • Meet only briefly at incubation mounds
• Simultaneous polygyny
  • Males mate with multiple females at once (Elliott and Kirwan 2017)
• Serial polyandry
  • Females mate with different males during a breeding season (Elliott and Kirwan 2017)
    • Loyal to one male at a time

Courtship habitats

• Incubation mounds typically constructed in moist gullies and woodlands (Kaveney 1958; Jones and Göth 2008)
• See Incubation Mounds

Mate choice

• Göth (2007b) suggests that females select mounds, not males
  • Certain male characteristics (e.g., colored neck skin, courtship behaviors) may also attract females
• Females compete with one another for access to a mound (Göth 2007b)
  • May show loyalty to a male for several weeks
  • Usually chase other females away from the male’s mound
  • May be competing for access to more ideal incubation temperatures within a mound
    • Females observed to lay more eggs and larger eggs in the ideal temperature conditions of 32-35°C (89-95°F)
  • Females often visit the mound without laying (Birks 1999)
    • May gain information to assess mound or mate quality (Jones 1990b)

Courtship behavior and copulation

• Female behavior approaching a mound (Jones et al. 1995)
  • Moves slowly and quietly
  • Assumes a crouched position
    • Neck tucked in and tail folded
    • May fluff body feathers, droop wings, and spread tail
• Male behavior in response to female (Jones et al. 1995)
  • Male slowly walks around the top of the mound
  • Pecks at mound material
• Male display to female, away from the mound (Coles 1937; Dow 1988b; Jones et al. 1995)
  • Less common than female approach
  • Male displays by lowering his body to the ground and spreading his wings widely
• Males usually aggressive to females (Jones et al. 1995)
  • Females tolerate or avoid male advances that are unsolicited (Birks 1999)
  • Females sometimes solicit males, possibly to avoid harassment while digging and laying (Birks 1999)
  • Some males force copulations (Jones 1990a; Birks 1999)
  • Males appear to expect females to copulate in return for access to the mound (Birks 1999)
    • Have little direct control over female copulation behavior, except when female use mounds to lay eggs
    • Males may chase away females that they did not mate with (Birks 1999)
• Copulations
  • Often occur at or near the mound (Jones et al. 1995)
  • Last about 5 (range: 3-11) seconds (Jones 1990a)
  • Often take place in the hour prior to egg laying and within a few minutes of a female’s arrival at the mound (60% of cases) (Birks 1999; Elliott and Kirwan 2017)
    • Rare among birds
    • Descending egg probably interferes with fertilization
  • Do not occur after egg-laying (Birks 1999; Elliott and Kirwan 2017)

Breeding

• Sexual maturity
  • Not known (Jones and Göth 2008)
  • Females (observations from managed care)
    • Göth et al. (2006) report that females did not lay eggs before 11 months of age
      • Possibly because mound sizes were unacceptable to females, aggression displayed by males, or other developmental factors
  • Males (observations from managed care)
    • Göth et al. (2006) report a range in first mound building behavior: 4.5 to 9 months of age
      • Some of this activity may have been “practice” nest building
      • All males in the study produced testosterone by 11 months
• Breeding season
  • Lasts 6-8 months (Elliott and Kirwan 2017)
    • May be up to 8-10 months (Jones 1988a)
    • Mound building starts May/June (Australian winter) (Jones 1988a)
  • Breeding activity lasts until January/February (southeast Queensland)
• Changes in physical characteristics during breeding
  • Wattle fuller during the breeding season (Elliott and Kirwan 2017)
    • Shrinks outside of the breeding season
  • Head and neck skin color can be much brighter during courtship (Elliott and Kirwan 2017)
    • Duller outside of the breeding season

Incubation strategy

• Mound incubation allows for development of more and larger eggs (Vleck et al. 1984)
  • Bird species that sit on their eggs can only incubate one small clutch at a time
• Mounds must be able to retain heat and moisture (Jones 1988b)
  • Male chooses a site in deep shade

Characteristics

• Materials
  • Mainly damp leaf litter and soil (Elliott and Kirwan 2017)
  • May also contain roots, sticks, and pebbles (Göth 2007b)
• Size
  • On average, about 85 cm (33.5 in) high and 300-410 cm (118.1-161.4 in) across (Jones 1988a; Elliott and Kirwan 2017)
    • Sometimes larger
• Mass
  • Contain 2-4 t (4,480-8,960 lb) of material (Elliott and Kirwan 2017)
  • Much more material on Kangaroo Island: 3-11 t (Seymour and Bradford 1992)
• Internal temperature (Elliott and Kirwan 2017, and as noted)
  • 31-36°C (87-97°F)
  • Large mounds retain enough heat to maintain stable temperatures for weeks, possibly months (Seymour 1995)
    • Influenced by moisture content

Construction

(Elliott and Kirwan 2017, except as noted)

• Mounds built by breeding males
  • Usually build a new mound (Jones 1988b)
    • Built in a different location than past few years
    • Not uncommon to build on top of an old mound
  • Takes about 37 (range: 14-77) days
  • Use strong legs and feet to rake together leaf litter and soil into long, narrow strips
    • Up to 100 m, or 330 ft, long (Jones and Göth 2008)
    • Does this for up to two weeks before forming material into a mound
  • Nesting materials initially piled high, but flatten with time (Jones et al. 1995)
• Usually built in shady areas with closed canopy and an abundance of leaf litter (not eucalyptus)
• Exception to mound building
  • This species is known to occasionally use human-made compost heaps (Elliott and Kirwan 2017)

Maintenance

• Males actively maintain their mounds (Seymour 1995; Göth and Astheimer 2006; Göth 2007a)
  • Activities (Jones 1988a)
    • Raking
      • Gather leaf litter and add it to mound
    • Mixing
      • Incorporate new mound material and mix surface layers (horizontal mixing)
      • Dig and refill holes (vertical mixing)
    • Assess mound temperatures while digging holes
      • Exact mechanism untested
        • May use head and neck skin
  • Maintain for up to 8 months (Jones et al. 1995)
• Stay near mounds for most of the day (Jones et al. 1995)
• Defend mound site against more dominant males trying to steal the mound (Jones 1988b; Jones and Göth 2008)
  • Younger males often can’t defend their nests against older, more dominant males (Jones 1990b)
• Spend considerable time adding vegetation/soil and rearranging mound material (Jones 1990a; Frith 2008; Jones and Göth 2008)
  • Far less time intensive, compared to construction phase
  • Mix mound material (Jones and Göth 2008)
    • Horizontally rake surface layers
    • Dig deep holes for vertical mixing
    • Benefits
      • Aids decomposition, stabilizing heat for incubation
      • Underground spaces supplied with more oxygen
        • Important to newly hatched chicks, which breathe heavily, as they dig to exit the mound
• Temperature regulation (Göth 2007a)
  • Adjust the nests’ temperature by adding material (warmer) or removing material (cooler)
  • Males vary in their ability to regulate the mound’s incubation temperature
    • Ability likely increases with age and experience
• See Incubation and Hatching

Egg

• Size
  • Large (Birks 1999; Göth 2007b)
  • Dimensions
    • A. l. lathami (Vleck et al. 1984; Jones et al. 1995)
      • Approximately 83-94 x 59 mm (8.3-9.4-5.9 cm)
    • A. l. purpureicollis (Jones et al. 1995)
      • Approximately 81-99 x 54-61 mm (8.1-9.9 x 5.4-6.1 cm)
• Weight
  • Heavy (Birks 1999)
    • About 10% of a Brush-turkey’s body mass
  • About 200 g (7 oz), on average (Göth 2007b; Eiby and Booth 2009)
• Yolk
  • Large
    • Makes up 50% of all egg contents (Vleck et al. 1984; Seymour 1991)
    • Supplies the energy a chick needs during the long incubation period and to dig out of the incubation mound
• Shell
  • Color
    • White (Jones et al. 1995)
  • Thickness
    • 1.5 times thinner than a chicken’s eggshell (Grellet-Tinner et al. 2017)
    • Thin surface makes shell more permeable to oxygen (combatting the loss of oxygen to microbes during decomposition) (Seymour 1991)
  • Surface
    • Covered in tiny, microscopic spheres made of calcium phosphate (D’Alba et al. 2014; Grellet-Tinner et al. 2017)
      • Rare – most bird eggshells contain calcium carbonate and glycoproteins instead
      • Protects egg from organic acids in nest material (Grellet-Tinner et al. 2017)
        • Acids cause eggshell thinning
      • Rough surface makes eggs hydrophobic (D’Alba et al. 2014)
        • Prevents bacteria from attaching and infecting the egg
        • Prevents biofilms (e.g., from raindrops) from forming on the shell
          • Biofilms can block the pores that allow oxygen to pass to the embryo
    • Contains Y-shaped pores not found in any extant bird (Grellet-Tinner et al. 2017)
      • Also present in eggshells of a group of dinosaurs called titanosaurs

Egg laying

• Female Brush-turkeys lay more eggs than most other bird species (Birks 1999)
• Egg production
  • A female lays eggs over a period of up to eight months (Jones and Göth 2008)
    • Lays one egg at a time (no clutches)
  • Can lay 15-27 eggs in a season (Elliott and Kirwan 2017)
• Laying in relationship to mound and males
  • Several females may lay in a single mound, protected by a single male (Elliott and Kirwan 2017)
    • Up to 58 eggs observed in a single mound in a season (Jones et al. 1995; Elliott and Kirwan 2017)
    • The average may be closer to 15 eggs per mound
  • A female lays series of eggs with different males (Birks 1999)
    • 5-10 eggs with one male
    • Then a new series of eggs with a different male
    • May lay eggs in up to five different mounds in a season
  • Eggs may be located anywhere within the mound, not just the center (Grellet-Tinner et al. 2017)
• Behavior
  • To access warmer areas of the mound, a female digs a long, tunnel-like “egg chamber” (Grellet-Tinner et al. 2017)
    • Takes 30-45 minutes (Jones 1988a; Jones et al. 1995)
  • When the female approves of the chamber’s temperature, she lays the egg into it (Jones et al. 1995; Grellet-Tinner et al. 2017)
    • After laying, she stamps her feet to backfill the tunnel
    • Takes about 20 minutes
  • Male often disrupts the female’s work (Jones et al. 1995, except as noted)
    • After laying, male usually chases her away
    • Male closes the hole, if the female does not, to prevent heat loss (Jones and Göth 2008)
    • Male then makes repairs to the nest
• Paternity
  • In some cases, 20-44% of eggs laid within a mound may not have been sired by the mound owner (Birks 1997)

Incubation and hatching

• Incubation occurs as microbes (i.e., “microorganisms”) and fungi decompose organic matter that makes up the nesting mound (Jones and Göth 2008)
  • Male adds new material to the mound throughout the breeding season to maintain heat production
• Incubation period
  • 47-52 days (in managed care) (Elliott and Kirwan 2017)
    • Eiby and Booth (2008) report 42-47 days in Queensland
  • Relatively long incubation period
    • May allow time for a chick’s wings to more fully develop, to aid dispersal and to escape from predators (Dial and Jackson 2011)
• Effects of incubation temperature
  • Mechanism for sex determination in Brush-turkeys is unclear (Ortega et al. 2017)
    • Brush-turkeys possess classic avian sex chromosomes, but maternal conditions prior to ovulation might also affect egg composition and offspring sex ratio
  • Very high or very low temperatures increase embryo morality (Göth and Booth 2005)
    • Sex-biased mortality (Eiby et al. 2008)
      • Male mortality higher at high temperatures
      • Female mortality higher at low temperatures
  • Eggs incubated at lower average temperatures take longer to hatch (Göth 2007a; Eiby and Booth 2008)
    • Less benefit to chick at hatching:
      • Have less stored energy in their residual yolk
      • Weigh less
      • Take longer to dig out of the mound
• Nest temperatures (Eiby and Booth 2008)
  • Average 34-35°C (93-95°F); range: 24.5-40.7°C (76-105°F)
  • Embryos experience prolonged periods of less-than-optimal temperatures, but appear to cope with extremes of hot and cold
    • Heavy rain cools the eggs, resulting in delayed hatching and smaller young
• Hatching
  • Chicks in the same mound hatch at different times (Göth 2001)
  • Hatch at a large size (Starck and Sutter 2000)
    • Weight at hatching: about 80 g (2.82 oz) (Jones et al. 1995)
    • At 20 days old, weigh about 200 g (7 oz) (Marchant and Higgins 1993)
  • Break eggshell with their legs, feet, and back (Seymour 1991; Göth 2002)
    • This may create a space for breathing, while underground
    • Do not use an “egg tooth,” unlike other bird species
  • Begin breathing after breaking through the eggshell (Marchant and Higgins 1993)

Exit from the mound

(Seymour 1991; Göth 2002, except as noted)

• Parents do not assist
• Hatching occurs up to 1 m ( 3 ft) deep within mound (Darryl Jones, personal communication, 2018)
• Chicks rest after hatching
  • On average, 16 hours
  • Their lungs develop full breathing function
• After resting, dig upwards to the surface
  • Lay on back and scrape at soil with feet
  • Maintain space around themselves in order to breathe
  • Preen in between bouts of digging
    • Mud on feathers could cause hypothermia
• Takes 40 hours (range: 26-55), on average, to dig out of the mound
  • Includes resting time
• Also see Development

Role of males

• Regulate temperature of the incubation mound (Jones et al. 1995)
• Provide no other care (Göth 2002)

Role of females

• Provide no care (Göth 2007b)
  • Do not participate in incubation or after-hatching care
• Invest considerable time in mound/mate choice (Göth 2007b)

Chick description

• Feathers soft and downy (Elliott and Kirwan 2017)
• Cryptic coloration (Jones et al. 1995)
  • Body brown
  • Head often a lighter brown
  • Some parts reddish (chest, crown) or buff (neck, chin, throat, some of the head)
  • Chest and belly faintly barred with gray
  • Iris light brown
  • Bill, leg, and foot coloration similar to adults
• Wings
  • Large (Dial and Jackson 2011)
  • Well-developed feathers, fully developed at hatching (Elliott and Kirwan 2017; Starck 1993; Göth 2002)

Chick adaptations and behaviors

• Chicks are physically and behaviorally well-developed (Elliott and Kirwan 2017)
• Highly independent
• Solitary (Marchant and Higgins 1993)
  • Do not roost communally
  • May congregate around food or for shelter
• Seek high roosts and refuges when they sense danger (Jones and Göth 2008)
• Appear to learn to select edible foods through trial-and-error (Göth and Proctor 2002)

Reaching adulthood

• Grow quickly (Jones and Göth 2008)
  • By nine months of age, juveniles are nearly indistinguishable from adults (Jones and Göth 2008)
  • By 10 months, reach adult body mass
• Changes in plumage
  • At two weeks of age (Jones and Göth 2008)
    • Tail feathers first appear
    • Lose head and neck feathers
      • Colorful bare skin is exposed
  • By 13 weeks of age, brown feathers are replaced by black feathers (Wong 1999)
  • Also see Plumage

Wild populations

• Not well-studied (Jones and Göth 2008)
• At least nine years (Jones and Göth 2008)

Managed care

• No AZA estimates

Survival rates

• Hatching success rates are high (Jones 1988c; Eiby and Booth 2008; Elliott and Kirwan 2017)
  • More than 85% of eggs hatch
• Chick survival rates
  • Intense predation pressure during the first three weeks of life
    • 0-12% survival in one study in Brisbane, Queensland (Göth and Vogel 2002)
• Survival to subadult stage is low (Elliott and Kirwan 2017)
  • Only 3-10% survival

Predators

• Eggs, chicks, young
  • Cats (Marchant and Higgins 1993; Elliott and Kirwan 2017)
  • Foxes (Marchant and Higgins 1993; Elliott and Kirwan 2017)
  • Pigs (Marchant and Higgins 1993; Elliott and Kirwan 2017)
    • Eggs
    • Damage incubation mounds
  • Powerful Owl (Ninox strenura) (Göth 2012)
  • Monitor lizards (Kaveney 1958; Marchant and Higgins 1993; Jones and Göth 2008)
  • Possibly snakes (unconfirmed) (Marchant and Higgins 1993)
• Adults (Göth et al. 2006; Elliott and Kirwan 2017, except as noted)
  • Cats
  • Foxes
  • Dogs and dingoes
  • Quoll (Jones and Göth 2008)

An 1887 illustration of a male Australian Brush-turkey scratching leaf litter behind him, while building an incubation mound.

Image credit: G. Mirtzel. In: "The Brush Turkey." Scientific American 57(11): p. 162. No known copyright restrictions.

Australian Brush-turkey chicks have brown body plumage, often with tints of red on their head.

Chicks live independently of their parents and other chicks.

Image credit: Maureen Goninan via Wikimedia Commons. Creative Commons License 3.0.