The Barnacle Goose (Branta leucopsis) is an Arctic-breeding bird known for one of the most dramatic and perilous parenting behaviors in the animal kingdom. Shortly after hatching, the tiny, flightless goslings must launch themselves from cliffs often hundreds of feet high. This shocking freefall, which can look like a death plunge, is not a choice but a severe biological necessity forced by the parents’ initial need to protect their young from danger.
Nesting Location Selection
Adult Barnacle Geese choose high, sheer cliff faces and rocky outcrops that are inaccessible to land-based predators like the Arctic fox and polar bear. This elevation provides safety for the incubating female and her clutch of eggs during the 25-day incubation period. However, the location that secures the eggs creates a life-threatening dilemma for the newly hatched goslings. The parents trade a short-term risk of predation for a massive, immediate risk of injury for their young.
Necessity of Leaving the Nest
The high cliff nests lack suitable food sources for the rapidly growing young. Barnacle Goose goslings are precocial, meaning they can walk and forage immediately after hatching, but they are not fed by their parents. The ledges only offer sparse mosses or lichen, insufficient to fuel the goslings’ growth.
The family must move quickly to the rich, grazing marshlands and tundra below to find the grasses the young need. Goslings will starve if they do not reach the feeding grounds within 36 to 72 hours of hatching. This timing is constrained by their physical development; they must be light enough to absorb the impact, which only works during these first few days of life.
The Fledgling Freefall
The descent is initiated by the parents, who call repeatedly from the base of the cliff to encourage the young to jump. The day-old goslings, unable to fly, plummet hundreds of feet toward the ground. Their survival is due to specific physical characteristics.
Goslings are extremely lightweight, and their dense downy feathers act like a cushion to absorb the impact. Their bones are also notably soft during this early period, helping them survive a fall that would be fatal just a week later when their skeletons are more rigid.
Approximately 90% of the goslings manage to survive the initial fall, often bouncing off rocks and slopes on their way down. However, the noisy commotion of the descent attracts predators waiting below. Upon landing, the parents must quickly herd their dazed young away from opportunistic scavengers like gulls and Arctic foxes. Despite the high success rate of the fall itself, the gauntlet of predators on the ground means that only about 50% of the goslings survive their first month of life.