Looks Like a Loon, But is it REALLY a Loon??

There’s a bird swimming on the lake, but is it really a loon?? It may be worth while to look in a field guide to be sure. Loons are often confused with other waterbirds, especially Common Mergansers (Mergus merganser) and cormorants (Phalacrocorax spp.), that also have a sharply pointed bill and are often swimming with a similar profile.

Here are some ways to tell them apart:

Common Loons:

• Both male and female adult loons are black and white in their breeding plumage.
• In their winter or late fall plumage, loons have gray, dull feathers and loon very similar to juvenile loons.
• Juvenile loons have gray feathers in their immature plumage. They get their feathers at about 8-9 weeks old. At this point, they are almost the size of their parents.
• Loons start nesting in May and incubation lasts almost a month. If you see a gray bird with a black and white bird on the water in April or early May, you are probably seeing a Common Merganser.
• Loons only have 1-3 chicks. If you see a bird with more than 3 chicks, it is probably a merganser or other waterbird.
• Very young loon chicks are black and downy. When slightly older (~2 weeks to ~8 weeks old), they are brown and downy.
• Loons have unique vocalizations – wails, tremolos, yodels, and hoots. Other waterbirds do not have such calls.
• Loons do not normally walk on land because their body is so specialized for swimming and they cannot easily stand upright. They only come to shore to nest or if they are sick.
• Loons need to “run” on the water before they can take off and get airborne.

Common Mergansers: Of the three merganser species (Common = Mergus merganser, Hooded = Lophodytes cucullatus, and Red-Breasted = Mergus serrator), Common Mergansers are the ones most easily mistaken for loons.

Look for these characteristics of Common Mergansers:

• Male Common Mergansers are black and white in their breeding plumage (from ~November-June) – they are often mistaken for Common Loons.
• Female Common Mergansers are gray with a reddish head. Nonbreeding males (~July-October) and juveniles look like females.
• Mergansers usually raise many chicks (>3) and occasionally a female will end up with more than one brood, so sometimes one adult bird will have a dozen or more chicks swimming with her.
• Adult mergansers are smaller than adult loons, weighing ~3-4 pounds, while loons can weigh up to 13-14 pounds for a big male.
• Mergansers usually swim along shorelines in groups.
• Mergansers often come to shore or stand or sleep on logs along the shoreline.
• Mergansers can take off from the water.

Cormorants: In Northeastern North America, Double-Crested Cormorants (Phalacrocorax auritus) are sometimes mistaken for Common Loons. These characteristics of cormorants should help you distinguish them from Common Loons:

• Adult cormorants are all black except for a little color around their face.
• Juvenile cormorants are pale around the head, neck, and chest. They have a dark back and belly.
• Cormorants are capable of standing upright, and are often observed standing on posts and rocks near the shoreline.
• Cormorant feathers are not water-repellent, so they dry their feathers by extending their wings while they stand on shore. They spend much less time in the water than do loons or mergansers because they have to dry their feathers regularly.
• Cormorants can take off from the water, although they usually run for a short distance before becoming airborne.
• Cormorants have a very stiff tail that can stand upright when they are swimming.
• Adult cormorants weigh ~3-4 pounds, and so are smaller than adult loons.
• Cormorants have a long narrow neck that looks smaller than a loon’s neck.
• Cormorants often swim in groups.
• Cormorants are colonial nesters, and usually nest in trees or shrubs.