Northern fulmars are monogamous and rejoin their mates each year at the same nest site for breeding. If an individual's mate dies, they will mate with a young, inexperienced mate following year, but at the same nest site. Males and females associate at the nesting colony for a few weeks before they lay an egg. They copulate frequently, then both depart to forage during the pre-laying phase.
Mating System: monogamous
During the pre-laying period, females store sperm in their reproductive tract and begin the process of yolk formation, which takes about 23 days. After yolk formation, females ovulate, the egg is fertilized, and the female returns to the colony and lays her egg within a few hours of arrival. Egg-laying occurs about 3 weeks after breeding.
Northern fulmars begin to breed in April and lay their eggs in late May to early June in large colonies on ledges and among rocks. They may also nest in areas with more soil and vegetation than other seabirds and will even nest on buildings and walls. Nests are fairly simple scrapes, sometimes lined with bits of vegetation. From 80 to 99% of nests are re-used by at least 1 member of the original pair each year. Females lay a single, white egg and incubation lasts for 47 to 53 days. The process of hatching takes from 4 to 5 days. Young fledge at 49 to 58 days in early September, with the last young northern fulmars leaving their natal sites by early October. Sexual maturity is not reached until 5 to 20 years old (average 8 years in males, 12 years in females).
Breeding interval: Northern fulmars breed once yearly.
Breeding season: Breeding occurs in the late spring and early summer, beginning in May.
Range eggs per season: 1 to 1.
Range time to hatching: 47 to 53 days.
Range fledging age: 49 to 58 days.
Average fledging age: 53 days.
Range age at sexual or reproductive maturity (female): 5 to 20 years.
Average age at sexual or reproductive maturity (female): 12 years.
Range age at sexual or reproductive maturity (male): 5 to 20 years.
Average age at sexual or reproductive maturity (male): 8 years.
Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sperm-storing
Average eggs per season: 1.
Both parents incubate the eggs, staying on the nest for from 1 to 11 (average 4.6) days until relieved by the other parent. Males often take particularly long incubation shifts at the beginning of incubation, presumably to allow the female to recover from laying the egg. Young hatch with a light covering of down and are closely tended by parents for 10 to 16 days after hatching, after which parents primarily visit the nest to feed their young. They are able to thermoregulate at 3 to 6 days old. Parents feed their young by regurgitation in response to the chick's food begging call. Young fledge at 49 to 58 (average 53) days old, about 4 to 5 days after the parents have stopped feeding them. Young fledge at 115 to 119% of adult body mass.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female)