The common loon, scientifically known as Gavia immer, is a large diving waterbird that breeds in forested lakes and large ponds across Canada and the northern United States. With its striking black-and-white plumage and distinctive yodeling calls, the loon is a symbol of wilderness and a familiar sight to many who enjoy outdoor recreational activities in northern regions.
However, to the untrained eye, the common loon can be mistaken for similar looking diving birds that inhabit the same aquatic habitats. This article will examine what other species of waterfowl resemble the iconic loon, discuss how to differentiate them, and provide an overview of their identification, habitat, and behavior. Equipped with this knowledge, birdwatchers and nature enthusiasts will be better able to positively identify loons in the field.
Birds Commonly Mistaken for Loons
Several species are frequently confused with the common loon due to similarities in appearance and behavior. The birds most often mistaken for loons include:
Horned Grebe
The horned grebe (Podiceps auritus) is a small waterbird that breeds across northern North America. Like loons, they have black heads and necks, along with white underparts. However, horned grebes are much smaller with slender, pointed bills. Their necks lack the thick black and white stripes of loons. In breeding plumage, horned grebes have distinctive yellow tufts behind their eyes that loons lack. They also have flared tail feathers.
Red-throated Loon
The red-throated loon (Gavia stellata) is a closely related species that overlaps in range with the common loon. As its name suggests, it can be identified by its reddish-brown throat patch, which common loons lack. Red-throated loons are also smaller with slimmer bills than common loons. Their backs have more white speckling. In breeding plumage, red-throated loons have rusty color on the head and neck.
Eared Grebe
Eared grebes (Podiceps nigricollis) are small waterbirds with black necks and prominent ear tufts. Like loons, they are adept divers and swim low in the water. However, eared grebes have sharp, thin bills and lack the hefty spear-like bill of a loon. Their necks also appear slimmer and more slender. Compared to loons, they have proportionately larger heads and fluffier rear ends.
Western Grebe
The western grebe (Aechmophorus occidentalis) is a large grebe species found in western North America. They share the black-and-white coloration of loons but can be identified by their thinner, swan-like necks. Western grebes have long, pointed bills and lack the chunky head profile of loons. In breeding plumage, they have colorful yellow feathers on their heads.
Double-crested Cormorant
Like loons, double-crested cormorants (Phalacrocorax auritus) are large, black waterbirds. However, cormorants have slender, kinked necks and longer, hooked bills. When swimming, they ride higher in the water with their bodies partially submerged unlike the low, flat profile of loons. Breeding cormorants sport two head crests that give the species its name.
Distinguishing Features of Loons
When differentiating loons from lookalike waterbirds, there are several key identification markers to look for:
Size and Shape
Loons are large, bulky birds measuring 25-50 inches in length with wingspans of 42-60 inches. They have short, stout bodies with thick necks and large dagger-like bills. Loons sit low and flat in the water rather than riding high like cormorants and grebes.
Plumage
Adult common loons have black heads and necks with white speckling and stripes. Their backs are black and their underparts are white. The plumage is strikingly bold and crisp compared to more subdued lookalikes. The cheek patch is also distinctive. Juvenile loons have drabber gray coloration.
Behavior
Loons spend most of their time swimming underwater rather than perched on land. They propel through the water using their feet to “fly” through the water in search of fish. Loons need a lengthy runway across the water to take flight. In flight, they maintain a flat profile with the neck and feet extended.
Species | Key Identification Features |
---|---|
Common Loon | – Large, heavy spear-like bill – Thick neck with crisp black and white stripes – Checkered back and white underparts – Red eyes – Low, flat body profile in water |
Horned Grebe | – Small waterbird with thin, pointed bill – Slender neck lacks bold pattern – Yellow ear tufts in breeding plumage – Flared tail feathers |
Red-throated Loon | – Smaller with slimmer bill than Common Loon – Rusty red throat patch – Speckled back |
Eared Grebe | – Small with thin, pointed bill – Long ear tufts – Small head and fluffy rear – Rides high in water |
Western Grebe | – Long, thin neck – Slender yellow bill – Colorful yellow head feathers |
Double-crested Cormorant | – Long, thin neck with hook bill – Rides high in water – Partial back crest |
Habitat and Range
Understanding where loons live and breed compared to similar species also aids identification:
Common Loon
Common loons inhabit lakes, ponds, and reservoirs across Canada, Alaska, and the northern U.S. states. They prefer large, clear bodies of water with plenty of small fish.NEST. Loons nest along quiet forested shorelines and sheltered bays.
Horned Grebe
Found on small ponds and marshy wetlands across Canada and into the central U.S. Breeds on floating vegetation mats in shallow water areas. Winters along Pacific and Atlantic coasts.
Red-throated Loon
Occurs on coastal areas and inland lakes throughout Alaska, Canada, and northern U.S. Nests along Arctic coasts and tundra lakes. Winters farther south along seacoasts.
Eared Grebe
Inhabits small ponds and wetlands throughout western North America. Breeds across central U.S. and southwestern Canada. Winters along Pacific coast to Mexico.
Western Grebe
Breeds on lakes and marshes of western North America. Winters along Pacific coast from Mexico to Canada. Occurs offshore and along marine habitats.
Double-crested Cormorant
Along coasts, rivers, and lakes across North America. Nests on islands and cliffs. Winters along southern U.S., Mexico, and Central America coasts.
Behavior and Ecology
The behavior of loons also sets them apart from similar species:
Diving
Loons are pursuit divers that use their feet for underwater propulsion. They chase and catch small fish, diving up to 200 feet below the surface. Loons may stay submerged for up to 5 minutes.
Swimming
Loons sit very low in the water with their bodies flattened. They use their feet like boat paddles to “fly” through the water. Their legs are positioned far back on their bodies to aid swimming.
Flight
Loons require an exceptionally long runway over water to gain enough speed for takeoff. In flight they hold their necks and feet extended. Their wings make distinctive rapid wingbeats.
Voice
The wailing, yodeling calls of loons are a distinctive sound of northern wilderness areas. Males and females perform duets to defend territory.
Predators
Loons face threats from eagles, large gulls, and snapping turtles, which may raid nests. Pollution and lead poisoning also endanger some populations. Conservation efforts are ongoing.
Conclusion
While several waterbird species bear resemblance to loons, careful observation of size, shape, plumage patterns, habitat, behavior, and other clues enables confident identification. Loons are icons of northern aquatic habitats, where their haunting cries reverberate across clear lakes. Understanding how to properly differentiate loons from similar species will enrich birdwatching experiences and ensure accurate records that contribute to conservation. With a bit of practice, even novice birders can master loon identification and appreciation.