Magellanic penguins are a monogamous species that upholds their pair-bonds for many seasons. An unmated male attracts a mate first by calling, which is more accurately described as "braying" like a donkey. Once an interested female comes forward, the male will walk in a circle around her and eventually will rapidly pat her with his flippers. A breeding pair often performs mutual preening to uphold their pair-bond.
Male Magellanic penguins also fight each other for both nests and females. When males fight before females have laid eggs, the larger male typically wins. These winners are more likely to breed and thus have more chicks. The winners' nest sites tend to be more covered and protected from the elements as well. When fighting occurs after egg laying, the winner, regardless of size, is typically the owner of the nest that he is trying to protect.
Mating System: monogamous
Magellanic penguins nest close to shore. They prefer to build their nests under a bush, but will also dig burrows into substrate if necessary. They choose areas where the substrate is composed of small particles such as silt and clay and low amounts of sand. Magellanic penguins breed in dense colonies where nests may be only 123 to 253 cm apart. Adults will arrive at their breeding grounds in early September and lay two eggs in late October. The average annual reproductive success is 0.52 chicks per nest. The clutch hatches asymmetrically, and the first hatched generally is bigger and better able to obtain food from the parents. Thus, one chick typically dies from starvation unless there is an overabundance of food or the colony size is small. Eggs weigh 124.8 grams and are 7.5 cm long. The incubation period lasts for 40 to 42 days and the chick brooding period lasts from 24 to 29 days. The young fledge at 40 to 70 days old, typically during January to the beginning of March. Fledglings group together in creches and immediately take to the water, while adults remain on shore for several weeks to molt. Juvenile Magellanic penguins do not reproduce until 4 years of age.
Breeding interval: Magellanic penguins breed once every year after reaching maturity
Breeding season: The breeding season for Magellanic penguins occurs from September to February
Average eggs per season: 2.
Range time to hatching: 40 to 42 days.
Range fledging age: 40 to 70 days.
Range time to independence: 40 to 70 days.
Average age at sexual or reproductive maturity (female): 4 years.
Average age at sexual or reproductive maturity (male): 4 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate)
Average eggs per season: 1.
Average age at sexual or reproductive maturity (male)
Sex: male: 1040 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 1040 days.
Both male and female penguins defend their nest, eggs, and young. Once the clutch is laid, incubation duties are shared and initially each parent will perform a two-week long shift. Parents switch more frequently as the incubation period progresses. When the young hatch after 40 to 42 days, they are semi-altricial meaning they are downy, immobile, and completely dependent on their parents for food and temperature regulation. Parents continue to alternate incubating and foraging duties, and the young are fed through regurgitation. The young are constantly cared for and brooded for 24 to 29 days, after which the parents spend extended periods of time foraging and will return to the nest every 1 to 3 days. At 40 to 70 days old, the young fledge and immediately take to the water in large groups, or creches. Fledgling penguins do not receive further parental care, as the parents remain on shore to molt. Once the adults have fledged, mixed groups of juvenile and adult penguins migrate north to the wintering grounds.
Parental Investment: altricial ; male parental care ; female parental care ; pre-fertilization (Provisioning, Protecting: Male, Female); pre-hatching/birth (Provisioning: Male, Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female)