African Penguin (Spheniscus demersus) Fact Sheet: Reproduction & Development

Monogamous

• Promiscuous copulation has been observed, however (Eggleton and Siegfried 1979)

Courtship (from Eggleton and Siegfried 1979 unless otherwise noted)

• Mate selection
• Female selects male
• Mating behavior highly ritualized
• Characteristic displays
• "Ecstatic Display"
  • Male advertisement of ownership and reproductive availability
  • Largely performed standing (rarely seated)
  • Slowly stretches head and bill toward sky, opening bill as head raises
  • Flippers raised at side nearly parallel with ground
  • Breast and base of throat begin silent heave that turns into throbs, ending in a full bray as the head is thrown back with bill open wide
  • Flippers beat back and forth in rhythm with breast heaves
  • Entire cycle complete within a few seconds to a minute; may be repeated for an hour or longer
• "Oblique Stare Bow" (OSB)
  • Performed by prospecting, unmated females; behavior is returned by interested males
  • Bill dips low, onto breast, pointing at ground
  • Neck retracted or extended and arched over bill
  • Interested males will approach with OSB and may initiate courtship displays and copulation
• Courtship and copulation
  
  • Males attempt to attract females
    • Male approaches with OSB
    • Receptive females perform OSB as well
    • Male "sidles" female, both performing the same actions; male, with female following, returns to nest site where both maintain OSB
    • Male then crouches, bows head bringing bill close to body and vibrates his head side to side (known as the "Vibrating Head Shake" or VHS)
    • VHS followed by a symbolic nest scrape; male lies on breast, scraping backwards with one foot
  • Pre-copulatory display, "Arms Act"
    • A male approaches the receptive female with a bowing posture
    • Male arches head over hers, resting ventral surface of his chin and neck on the top of her head; his chest pressed against her back
    • Male gently pats female's sides with his flippers; he gently attempts pushing her to a seated position
• Copulation
  • Generally occurs at nest, sometimes elsewhere in colony or on beach
  • Female sits and male mounts, patting her sides with his flippers and treading on her back with his feet
  • Female holds tail stiffly upright while holding head horizontal
  • Male bends over female, holding crest erect; he vibrates his bill placing, his tail over hers
  • 69-228 seconds in duration (from mounting to dismounting)

Nest selection

• Nest site selected by male (Brown et al. 1982)

Timing

• Prolonged breeding season with several peaks (Crawford et al. 1990; Crawford et al. 1999)
  • Breeding recorded in all months (Wolfaardt et al. 2009)
  • Birds begin laying first clutches as early as January across most of their range
• Breeding is highly variable within years, between seasons, and even between colonies on the same island within the same year (Crawford et al. 1990; Crawford et al. 1999; la Cock et al. 1987; Wolfaardt et al. 2009)

Nest construction

• 3 primary types; forms vary from island to island, and even within colonies on the same island
  • Burrows
    • Dug into sandy soil or guano
    • Traditional nesting technique; removal of guano by humans has made construction difficult at some nesting sites (Seddon and Van Heezik 1993a)
  • Burrow dimensions from one study (Frost et al. 1976a):
    • Mean depth = 56.2 cm (22.1 in)
    • Mean entrance height = 18.2 cm (7.2 in)
    • Mean entrance width = 32.6 cm (12.8)
  • Similar to, but smaller than those of the Magellanic penguin (Frost et al. 1976a)
  • Shallow scrapes (from Frost et al. 1976a; Seddon and Van Heezik 1991b; Sherley et al. 2012)
  • Depressions in sand, guano, or other soft substrate
  • Made using the bill, wings, and feet
  • Covered nests
  • Constructed under large rocks, boulders, or vegetation (la Cock et al. 1987; Seddon and Van Heezik 1991b; Sherley et al. 2012)
• Uncommonly constructed nests
• Nests reported in abandoned buildings (Sherley et al. 2012)
• Cave breeding reported in a small mainland population, Namibia (Simmons and Kemper 2003)
• Nests are lined with collected materials
  • Materials include twigs, feathers, bones, and stones (Eggleton and Siegfried 1979)
  • Collected by both parents
  • May be stolen from other nests

Clutch Characteristics

• Egg shell chalky, white
  • Mean shell thickness 0.6 mm (c. 0.02 in), in one study (Yom-Tov et al. 1986)
• 1-2 eggs per clutch (Brown et al. 1982; Crawford et al. 1999; Williams 1995; Seddon and Van Heezik 1991b)
  • Laid in 2-4 day intervals
  • First egg larger than second for two-egg clutches, generally (Seddon and Van Heezik 1991b; Williams 1995)
• Rarely three eggs in a single clutch
• Egg mass
• 99-118 g (Yom-Tov et al. 1986; Brown et al. 1982; Williams 1995)
• Egg dimensions (Williams and Cooper 1984)
  • First egg
    • Length: 62-76 mm (2.4-3.0 in)
    • Breadth: 47-55 mm (1.9-2.2 in)
  • Second egg
    • Length: 54-72 mm (2.1-2.8 in)
    • Breadth: 48-55 mm (1.9-2.2 in)
• Hatching
• Asynchronous
• Weigh c. 60 g (Brown et al. 1982)

Incubation (from Seddon and Van Heezik 1991c unless otherwise noted)

• "Sit" on eggs for 38-41 days (Brown et al. 1982; Seddon and Van Heezik 1991a; Sparks and Soper 1987)
• Sexes equally share incubation duty
• Incubation shift typically 2 days
• 11⁺ day shifts observed without indication of abandonment following shift change

Chick (from Seddon and Van Heezik 1993c unless otherwise noted)

• Development
• Proceeds quickly
• Eyes closed or partially so until about 6 days of age
• By 14 days, chicks are able to hold themselves upright
• By 3 weeks, chicks can stand and walk
• May leave the nest to explore for distances of 20 or more meters, returning to feed in late afternoon
• Molting
• First molt
• 325-710 g (0.7-1.6 lb) or around 14 days of age (Brown et al. 1982)
• Second molt
• 40-60 days (Brown et al. 1982)
• Lost before replacement by juvenile plumage (Brown et al. 1982)
• Aggressive toward others while losing down
• Fledge
• 70-90 days, mean 87 days in one study (HBW 2013; Seddon and Van Heezik 1991a)
• First hatched sibling may fledge more quickly, data unclear
• Size at fledge (Seddon and Van Heezik 1991a)
  • Range in weight: 1750-3000 g (3.9-6.6 lb)
  • Mean weight: 2252 g (5.0 lb) at fledging, in one study of 32 chicks
  • No clear difference in fledging weight between siblings

• Care
• Fed by both parents
• Chick begs  to induce parental feeding (Seddon and Van Heezik 1991a)
  • Food offered  by direct beak-to-beak regurgitation
• Form creches, or small groups, when left unguarded by parents; possibly for protection against weather, predators, or aggressive adults (Seddon and Van Heezik 1993a)

Juvenile (from Brown et al. 1982 unless otherwise noted)

• Juvenile plumage complete: 70-80 days
  • Adult plumage: 13-22 months (Whittington et al. 2000)
• Begin leaving home island: 70-118 days
  • Remain away for about one year
  • Return to land for molt

Adult (from Brown et al. 1982 unless otherwise noted)

• Age at first reproduction
• 4 years typical; range 2-7 years (Crawford et al. 1999; Crawford et al. 2000a; Whittington et al. 2005)
• Adults molt annually (Wolfaardt et al. 2009)
  • Every 221-546 days, with a mean of 349 days
  • During the molting process, adults remain on land and do not eat
  • Molting individuals are found on beaches, at nest sites, and in burrows
  • Typically completed between September and January

Wild populations

• Not reported

Managed care

• Median life expectancy
  • 17.8 years (male, female data combined) (AZA 2024)

Predation

• Cape fur seal, Arctocephalus pusillus pusillus (Crawford et al. 2001; David et al. 2003; Makhado et al. 2013; Marks et al. 1997)
  • Primarily of birds at sea, mostly adults; immatures also preyed upon
  • Ambush adults with full bellies on returning from foraging trips to feed chicks (P Whittington personal communication)
• Kelp gull (Larus dominicanus), sacred ibis (Threskiornis aethopicus), and rats (Rattus spp.) consume eggs and small chicks (Frost et al. 1976a; Frost et al. 1976b)
• Feral cats (Berruti 1986)
• Mole snakes (Pseudaspis cana) - one study on Robben Island (Dyer 1996)
• Possibly sharks, based on an examination of injuries to birds on islands and adjacent beaches of Algoa Bay (Randall et al. 1988)

Disease

• Avian cholera, Pasteurella multocid (Crawford et al. 1992)
• Spread via carcasses of dead birds and as a water born disease, originating from secretions of the nose and mouth

Annual survival rate

• 33-70% of adults in one study, 1979 to 1985 (la Cock et al. 1987)
• Annual survival rate at Dassen Island calculated as 0.84 (Wolfaardt et al. 2009)

African Penguin breeding colony.

Image credit: © Harvey Barrison from Flickr. Some rights reserved.

African Penguin parent arranging eggs in nest. It is uncommon for African Penguins to lay three eggs in a single clutch.

Image credit: © Mike Scott from Flickr. Some rights reserved.

African Penguin chicks, Boulder Beach, South Africa.

Image credit: © Daniele Colombo from Flickr. Some rights reserved.

Berruti (1986)
Brown et al. (1982)
Crawford et al. (1990)
Crawford et al. (1992)
Crawford et al. (1999)
Crawford et al. (2000a)
Crawford et al. (2001)
David et al. (2003)
Dyer (1996)
Eggleton and Siegfried (1979)
Frost et al. (1976a)
Frost et al. (1976b)
HBW (2013)
la Cock et al. (1987)
Makhado et al. (2013)
Marks et al. (1997)
Randall et al. (1988)
Rutgers and Norris (1970)
Seddon and Van Heezik  (1991a)
Seddon and Van Heezik  (1991b)
Seddon and Van Heezik  (1991c)
Seddon and Van Heezik  (1993a)
Seddon and Van Heezik  (1993b)
Seddon and Van Heezik  (1993c)
Sherley et al. (2012)
Simmons and Kemper (2003)
Sparks and Soper (1987)
Spellerberg (1975)
Whittington et al. (2000)
Whittington et al. (2005)
Williams (1995)
Williams and Cooper (1984)
Wolfaardt et al. (2009)
Yom-Tov et al. (1986)