Penguins head to higher, rockier ground primarily to protect their eggs and chicks from flooding. In Antarctica and the sub-Antarctic islands, melting snow and ice can destroy nests at low elevations, so many penguin species climb steep slopes and trek inland to find dry, well-drained terrain for breeding. It’s not about enjoying the view; it’s a survival strategy shaped by some of the harshest nesting conditions on Earth.
Snow Melt and Flooding Drive Penguins Uphill
The single biggest threat to a penguin nest at low elevation is water. As Antarctic summer arrives, snow and ice begin to melt, and that runoff flows downhill directly through nesting areas. Melting snow can chill or drown eggs and chicks, and excessive snow drift can bury nesting penguins entirely. For a species that lays just one or two eggs per season, losing a nest to flooding is a serious reproductive blow.
Gentoo penguins illustrate this clearly. They prefer nesting sites around 115 meters above sea level along the shore because snow at higher elevations tends to melt first, giving them dry ground earlier in the breeding season. The higher a nest sits, the less likely it is to flood as surrounding snow melts through the summer. Researchers studying Adélie penguin colonies have mapped flood risk across nesting sites using surface water flow models, confirming that nests in low-lying areas with large upslope snowfields face significantly greater flood risk than those on ridges and elevated ground.
Ice-Free Rock Is Extremely Scarce
Less than 5% of the Antarctic coastline offers terrain that is free from permanent ice and snow. Penguins need bare rock or gravel to build their nests, typically piling small stones into a mound that keeps eggs off the frozen ground and allows water to drain away. That means suitable nesting habitat is in fierce demand, and much of it happens to be on elevated, rocky slopes rather than flat coastal ice.
Adélie penguins, one of only two species that breed exclusively in Antarctica, face especially strong pressure to find these rare patches of exposed ground. Their colonies cluster on rocky outcrops, ridgelines, and volcanic terrain, sometimes at sites with elevation changes of 150 meters or more. At a colony like Cape Crozier on Ross Island, the landscape features large ridges and hills that create variable microclimates. Some of these elevated spots offer better wind shelter, less snow accumulation, and superior drainage compared to flatter ground closer to the water.
Steep Slopes Don’t Bother Some Species
Chinstrap penguins take mountain nesting to an extreme. They actively prefer steep, rocky slopes and seem unbothered by terrain that would challenge most ground-nesting birds. Their largest colony sits on the volcanic slopes of Zavodovski Island in the South Sandwich Islands, where roughly two million chinstrap penguins breed on the flanks of an active volcano. The steep terrain offers abundant exposed rock, good drainage, and early snowmelt, all of which make it prime real estate despite the climb.
Chinstrap colonies are scattered across the Scotia Sea region, from the South Sandwich and South Orkney Islands to the South Shetland Islands and the northern Antarctic Peninsula. In nearly all of these locations, the birds choose rocky surfaces well above the waterline rather than nesting on flat coastal ground.
How Far Penguins Will Travel
Emperor penguins hold the record for inland treks, traveling 50 to 120 kilometers from the coastline to reach their breeding sites on stable sea ice. Some colonies form even farther from open water, requiring walks of up to 75 miles. This seems counterintuitive since penguins feed exclusively in the ocean, but the stability of the breeding surface matters more than proximity to food. Emperor penguins need thick, flat sea ice that won’t break up during their months-long breeding cycle, and that ice is found well away from the coast.
King penguins spend 30 to 50% of their time on land and may walk several kilometers between their breeding colonies and the sea on each trip. Other species make shorter but still demanding journeys. Royal penguins on Macquarie Island collectively walk about 63 kilometers over the course of 22 round trips during a single breeding season.
The Energy Cost of Climbing
Walking is genuinely hard work for penguins. Their upright posture and short legs make them among the most energy-inefficient walkers of any bird. Multiple studies have confirmed that penguins burn significantly more calories per step than other ground-walking birds of similar size. Yet the total energy spent on walking turns out to be a surprisingly small fraction of their seasonal budget.
For king penguins, all that walking to and from the colony adds up to only about 1% of the energy they spend while on land. Emperor penguins making a 400-kilometer round trip over a breeding season use roughly 4% of their total seasonal energy on walking, which is meaningful but manageable for a 35-kilogram bird carrying large fat reserves. Royal penguins spend even less: an estimated 0.006% of their breeding-season energy budget goes toward their 63 kilometers of walking. So while the trek looks punishing, the caloric cost is small enough that the survival benefits of a well-drained, elevated nesting site far outweigh the price of getting there.
Terrain Shape Affects Nest Success
It’s not just elevation that matters. The specific shape of the terrain around a nest influences whether eggs survive. Slope steepness affects how well water drains away, but too much slope increases the chance of eggs rolling out of the nest. Wind exposure is another factor: ridges and hills create sheltered pockets on their leeward sides, but they also generate semi-permanent snow drifts that can bury nearby nests.
At Cape Crozier, researchers found that the colony’s dramatic terrain, with ridges rising to 150 meters, creates a patchwork of microclimates. Some subcolonies sit in well-drained, wind-sheltered spots with high breeding success, while others just a short distance away face heavy snow drift and flooding. By contrast, a flatter colony like Cape Royds, with only about 20 meters of elevation change, has more uniform conditions across the entire site. The tradeoff is that flatter colonies offer fewer of those prime elevated spots, which limits how large the colony can grow.
Penguins aren’t consciously analyzing drainage patterns, but over generations, the birds that choose higher, rockier ground successfully raise more chicks. That selective pressure has made mountain-seeking behavior a deeply ingrained part of penguin breeding biology across multiple species.