The common loon is a master of the deep, but struggles on solid ground.

Nature · Published 3 October 2026 Swipe more like this →

In short: With solid bones and specialized anatomy, the common loon is a formidable underwater hunter. Yet, this aquatic prowess comes at a cost: their legs are positioned so far back on their bodies that they are notoriously clumsy on land, requiring long stretches of open water to achieve flight.

The common loon, or Gavia immer, is a marvel of evolutionary adaptation for an aquatic life. Unlike most birds, which possess hollow, buoyant bones, the loon has solid bones that reduce buoyancy, allowing it to dive with ease. When hunting, these birds can expel air from their lungs and flatten their plumage to minimize drag, while their heart rate slows to conserve oxygen during underwater chases. To secure their slippery prey, they rely on sharp, rearward-pointing projections on their tongues and the roofs of their mouths.

Their life cycle is defined by a slow maturation process. While juveniles are independent by about 12 weeks, they typically spend their first two years on coastal waters before returning north. Breeding usually does not begin until the bird is around six years old. Despite this slow start, they can be remarkably long-lived; the oldest recorded individual was a female at least 29 years and 10 months old when identified in 2016, having been originally banded in 1989.

The loon's reliance on water is absolute. Because they require a 'runway' of 30 yards to a quarter-mile of water to gain enough speed for takeoff, they are vulnerable to becoming stranded on small ponds or even wet surfaces like highways, which they may mistake for water. During midwinter, they undergo a complete molt, rendering them flightless for several weeks. While their populations are currently considered of least concern, they face ongoing threats from human encroachment, pollution, and the ingestion of toxins, prompting the United States Forest Service to grant them special status.

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