Loons are fascinating waterbirds that spend their lives in lakes, rivers, and along coastlines across North America. One of the most iconic sounds of the northern wilderness is the eerie, wavering call of the loon echoing across a lake at dusk. As night falls and darkness blankets the water, you may wonder – where do loons go to rest? Where do these birds spend the night hours? Loons spend their nights resting comfortably on the water, floating on the lake surface with their heads tucked into their feathers. Read on to learn more about the nighttime habits of these iconic waterbirds!
Loon Habitats
Loons inhabit a variety of aquatic habitats across North America, including:
- Lakes – Loons prefer larger lakes that are over 20 acres in size. Lakes provide ample open water for loons to float on and dive beneath. Many loons return to nest on the same lake year after year.
- Rivers – Some loon species, like the Yellow-billed Loon, inhabit rivers in their breeding ranges. Rivers provide habitat similar to lakes.
- Coastlines – During migration and winter months, loons can be found along coastlines and estuaries. Nearshore areas provide habitat for feeding and resting.
In summer months, loons spend most of their time on freshwater lakes and ponds within their breeding territories. Here they build their nests, raise chicks, and molt into their winter plumage before migrating south. During migration and winter, loons expand into broader aquatic habitats along coasts, estuaries, and large rivers.
How Loons Spend Their Nights
When darkness falls across their watery habitat, loons remain resting on the water rather than flying to land. Since their bodies are specially adapted for swimming and diving, loons are quite comfortable spending nights afloat on the lake or river surface.
There are several key reasons why loons spend nights resting on the water:
- Buoyancy – Loons’ solid bones provide ballast and their waterproof feathers help them float stably on water overnight.
- Vulnerability on land – Loons’ legs are set far back on their bodies, which makes walking on land very difficult. At night on land they would be vulnerable to predators.
- Energy conservation – Flying takes energy! Remaining peacefully on the water allows loons to conserve energy.
- Territory protection – By staying on their breeding lakes at night, loons protect their nesting territories from competing loons.
- Safe from predators – Large lakes provide protection since loons can easily escape predators in open water.
How Do Loons Float and Balance on Water?
Loons possess special adaptations that allow them to float gracefully on the water for extended periods. Several key structural features help loons achieve balance and buoyancy:
- Dense bones – Loons’ bones are solid rather than air-filled, which provides ballast and weight to counteract their buoyant bodies.
- Feather density – Loons have thick layers of waterproof feathers that help trap air and keep their bodies floating high in the water.
- Foot placement – Having feet located so far back aids swimming, but it also helps adjust and maintain balance while floating.
- Wing adjustments – Loons can subtly adjust their wing and tail feather positioning to maintain optimal balance as they rest on the water overnight.
During the day, loons use their feet like rudders to stop and steer themselves on the water. At night, their legs hang down into the water for balance and stabilization as they rest. If you watch loons floating on a lake at night, you will see that they frequently paddle their feet to re-position and maintain balance through the hours of darkness.
How Do Loons Sleep on Water?
When loons spend nights floating on lakes and coastal bays, they are not always fully sleeping. Loons actually exhibit periods of deep sleep mixed with light dozing and alert wakefulness.
Some key facts about how loons sleep on the water:
- One brain hemisphere remains awake – Loons will sleep with only one hemisphere of their brain awake at a time, keeping one eye open to watch for threats.
- Bill tucked under feathers – Loons rest with their bill tucked into their back feathers to conserve heat.
- Paddle feet to reposition – Loons often paddle their feet to turn and reposition while dozing to maintain optimal balance.
- Sleep in pairs or groups – On breeding lakes, loons will sleep relatively close together, often in pairs or family groups, which allows for synchronized activity.
- Alert when disturbed – Loons resting on water will quickly become alert and defensive if distrubed by a predator or passing boat.
So while loons may appear to be serenely sleeping as they gently drift across the moonlit water, they are actually only partially sleeping. Their remarkable ability to rest on the water helps keep them safe from land-based predators that may try to ambush them at night.
Where Do Loons Spend Winter Nights?
When loons migrate away from their summer breeding lakes in fall, they winter along coastlines where they find new nocturnal roosting habitats. Here are some of the places loons spend nights during winter:
- Nearshore bays – Sheltered, shallow bays provide calm water for loons to float and feed.
- Estuaries – Estuarine areas where rivers meet the ocean provide habitat similar to lakes.
- Reservoirs – Some inland reservoirs resemble lakes and attract wintering loons.
- Power plant outfalls – Warm water from power plant discharge attracts baitfish, which in turn attracts loons.
- Docks and marinas – Well-lit, protected marinas can provide habitat for night-roosting in winter months.
During winter, loons may gather in loose flocks numbering in the hundreds on coastal bays where they spend nights together resting on the ocean surface. These flocks provide safety in numbers from potential threats.
Winter Adaptations for Roosting on the Ocean
Spending nights floating on the ocean requires some key physiological and behavioral adaptations:
- Salt gland function – To drink saltwater, loons rely on specialized salt glands above their eyes that concentrate and excrete excess salt.
- Countercurrent circulation – Vascular countercurrent circulation helps loons retain core body heat, even in frigid ocean environments.
- Offshore energy waves – Loons rest within or just beyond the crashing waves where ocean swells gently rock them at night.
- Group floating – By floating together in a flock, loons can synchronize their movements and spacing to help one another stay balanced on the swell.
Thanks to these adaptations, loons are well equipped to float rested on the ocean’s surface, even during storm conditions. Their winter nights are spent drifting over the rhythmic swells, paddling their feet, and sleeping with one eye open beneath the twinkling stars.
Threats to Loons at Night
Despite their aquatic adaptations, loons still face some threats and disturbances while resting on the water at night:
On Breeding Lakes
- Territorial conflicts – Aggressive fights between loons defending territories.
- Predators – Large fish, otters, mink, and raccoons may occasionally prey on loons.
- Human recreation – Boats or noisy shoreline activity can disrupt loon nesting.
- Fishing tackle – Loons can ingest lost fishing gear and lures, which are often lethal.
On Ocean Wintering Areas
- Oil spills – Oil destroys the waterproofing and insulation of feathers.
- Gill net entanglement – Loons diving at night risk becoming entangled in gill nets.
- Pollution – Ingesting heavy metals reduces loon immunity and reproduction.
- Climate change – Storm impacts, habitat loss, and prey declines may increase with warming.
Wildlife managers use floating rafts, warning signs, fishing tackle collection, and oil spill response to help reduce risks to loons resting on lakes and coasts at night. With supportive conservation policies, these iconic waterbirds will continue drifting across moonlit waters through the night.
Conclusion
Loons lead an aquatic lifestyle, and they extend that adaptation to their sleeping habits as well. Rather than taking flight to rest on land, loons remain floating on lakes, rivers, estuaries, and bays at night. Their dense bones provide ballast in the water, while overlapping waterproof feathers trap air to keep their bodies buoyant. Loons have special adaptations like solid bones, salt glands, and foot positioning that enable them to rest comfortably on the water. They sleep with one eye open and remain alert to potential dangers. While threats exist from habitat loss, pollution, and human disturbance, most loons continue to persist in their iconic nocturnal habit of drifting across the moonlit waters at night. Their eerie calls at dusk transition to serene silence under the stars as loons rest peacefully until dawn.
