Barnacle goslings are the baby offspring of barnacle geese. Barnacle geese build their nests on cliffs near the sea, sometimes as high as 700 feet above the ground. This leads to a dangerous situation where the goslings occasionally fall out of the nest before they are able to fly. Amazingly, the goslings are able to survive these falls which allows the species to continue to thrive. This article will examine how barnacle goslings are able to survive falls from such extreme heights.
How high do goslings fall from?
Barnacle geese typically build their nests on cliffs along the coasts of northern Europe and eastern North America. They choose nesting sites situated 100-700 feet above the ground, most commonly around 230 feet high. This is an astounding height for such a small, fragile baby bird to fall from. Based on the preferred nesting heights of barnacle geese, goslings likely fall anywhere from 100 to 700 feet to the ground below. That’s equivalent to a 7-70 story building! Falls from such heights would be fatal for most animals, but barnacle goslings have adaptations that allow them to survive.
What percent of goslings survive falls?
Researchers have found that while goslings do occasionally fall from their cliffside nests, the survival rate is quite high. One study conducted in Norway monitored 158 gosling falls and found that only 12 falls (7.6%) resulted in death. The other 92.4% of goslings survived the fall. Another study found 89% of goslings survived falls from nests 200 feet or higher in Scotland. The high survival rate suggests the goslings have physical attributes and instinctual behaviors that protect them during free falls.
How do goslings survive the impact?
When falling from such heights, the primary threat to goslings is the force of impact with the ground. However, goslings have several key adaptations that help them survive the collision:
Lightweight bodies
Goslings are very lightweight, weighing only 4.3-5.5 oz at birth. Their tiny bodies reach terminal velocity quickly, minimizing acceleration forces. The limited weight also reduces the impact force when hitting the ground.
Collapsible skeletons
Bird bones are hollow, reducing their weight. But goslings have especially flexible cartilage and thin leg bones that can collapse on impact, absorbing some of the shock.
Fluffy down feathers
Newly hatched goslings are covered in dense, fluffy down feathers up to 1 inch long. This downy coat cushions the impact and protects the gosling’s body.
Parachute posture
Goslings instinctually spread their wings and flatten their bodies when falling. This increases wind resistance and slows the fall, much like a parachute. Outstretched wings also distribute the impact over a larger area.
| Adaptation | Impact Reduction Mechanism |
|---|---|
| Lightweight body | Minimizes acceleration forces and impact energy |
| Collapsible skeleton | Absorbs shock by compressing on impact |
| Fluffy down feathers | Cushions the body like padding |
| Parachute posture | Increases drag to slow fall and distributes impact |
How do goslings orient themselves to land safely?
While their physical attributes protect goslings from impact, proper body orientation is also critical for safe landings. Fortunately, goslings have instinctual behaviors that cause them to reposition themselves as they fall:
Righting response
Goslings display innate righting behaviors to face upright. If tumbling through the air, they will spread a wing on the downward side to roll back upright. This ensures they land on their feet.
Parachute posture
In addition to slowing the descent, holding the wings spread wide and straight keeps the body horizontal and feet downward prior to collision. This is the optimal position for landing.
Leg extension
Just before impact, goslings extend their legs to be ready for contact and bending their knees to help absorb some energy. Their feet also have thick pads for shock absorption.
Neck withdrawal
Retracting the neck protects this critical but fragile area and prevents whiplash injuries.
| Instinctual Behavior | Landing Assistance |
|---|---|
| Righting response | Rotates body to upright position |
| Parachute posture | Orients feet downward |
| Leg extension | Prepares legs for impact |
| Neck withdrawal | Protects neck from injury |
How do parent geese help goslings survive falls?
Parent geese also demonstrate behaviors both before and after falls that improve the survival chances of their goslings:
Nest site selection
By choosing nest locations with soft landing spots like shrubs, grass, or sand below, geese give their goslings the best chance of surviving tumbles from the nest.
Brooding posture
Parent geese sit very still and upright in the nest to avoid nudging goslings over the edge. Their feathers form walls around the nest for containment.
Watchful waiting
After a fall, parent geese remain close by watching over the gosling until it recovers and begins walking on its own. This protects from predators.
Frequent feedings
Geese feed goslings frequently so they have energy stores to withstand falls shortly after eating. This rapid nourishment helps goslings bounce back quickly.
| Parental Behavior | Survival Assistance |
|---|---|
| Nest site selection | Provides soft landing surface |
| Brooding posture | Prevents accidental tumbles |
| Watchful waiting | Protects from predators after fall |
| Frequent feeding | Provides energy to recover quickly |
How do goslings behave after surviving a fall?
Goslings are quite resilient after surviving falls, displaying these instinctual behaviors:
Brief immobilization
Immediately after hitting the ground, goslings will remain still for several minutes to recover from the shock and assess for injuries. This also reduces predator detection.
Righting reflex
Once alert, goslings quickly flip themselves upright using their wings if they landed upside down or on their sides.
Calling
Goslings will start peeping loudly soon after getting upright. This attracts the attention of the parents.
Walking
The goslings soon regain mobility and start walking around unsteadily on land. Their legs may be slightly splayed initially after impact.
Swimming
If landing in water, goslings will start paddling with their feet to reach the shore. This innate swimming ability also helps them survive falls into water bodies.
Following parents
Once reunited with parents on shore, goslings will follow them closely on foot to the nest or a new brood foraging area.
Conclusion
The amazing ability of barnacle goslings to survive falls from extreme heights is made possible by their specialized physical attributes and innate behavioral instincts. Lightweight bodies, collapsible skeletons, cushioning down feathers, and parachute postures all help the goslings endure the impact forces when hitting the ground. Righting responses, leg extensions, and neck withdrawals then properly orient their bodies for safe landings. Parent geese also demonstrate caregiving behaviors that improve their goslings’ survival chances after tumbles from the nest. While fatal falls unfortunately still occur in a small percentage of cases, these adaptations allow barnacle goslings to continue thriving as a species despite their perilous nest locations high on cliffsides. Their resilience serves as a remarkable example of how evolution has shaped some species to survive environmental hazards that would prove lethal to most other animals. Clearly, barnacle goslings have a robust set of defenses that allows them to sustain their improbable lifestyles as high-rise nesters.
