Loons in Mercer, WisconsinWhat do loons look like? Loons are powerful, streamlined birds with red eyes, greenish black head, long tapered beak and black and white checkerboard plumage. 

How large are loons? The common loon (Gavia immer) stands approximately 25 inches tall, weighs between 8 and 11 pounds and has a wingspread of 5 feed. 

Are there different species of loon? There are four species of loons that exist in the northern hemisphere. The Common Loon, the Arctic Loon, the Yellow-Billed Loon, and the Red throated Loon.  The Common Loon is the only one found in northern Wisconsin, Michigan, Minnesota and Canada whereas the other (3) species are found in Northern Canada and Alaska. 

Are loons good swimmers? Loons are supreme rulers of their aquatic domain. With legs located well back on their sleek bodies, loons are superb swimmers easily capable of catching fish for food. 

Are loons good divers? Unlike other marine birds, loons have dense bones which permit them to dive to depths of 200 feet and remain submerged for 5 to 10 minutes. 

Do loons ever come to shore? Loons do come ashore but only to nest. With legs positioned behind their balance point, loons have great difficulty walking or even standing.  It is not unusual for loons to support some of their weight on land with their chests. 

Loons in Mercer WisconsinWhy are loons eyes red? The red is caused by a pigment in the retina that filters light when loons dive beneath the waters surface and allows for sight.

How can one tell the difference between the male and female loon? It is impossible to determine the sex of a loon without observing its internal organs. 


Where do loons go during the winter? Loons migrate south and east shortly before ice covers the lakes.  Exactly where they go is still not fully determined although it is generally believed loons winter somewhere along the southern Atlantic and Gulf Coasts.

Do loons migrate in flocks? Yes, in late autumn, generally well before the great freeze, loons congregate on large lakes and fly south together. 

Do immature loons return to the North Country after their first migration south? Young and immature loons are believed to spend two or three years in coastal waters beforemaking their first trip back to the North Country. 

How many loons inhabit a lake? Loons are territorial birds and generally only one pair is found on each lake, except for very large bodies of water where several pairs inhabit a lake. 

What size body of water can support a loon population? Research conducted by Wisconsin Project Loon Watch indicates that loons inhabit bodies of water as small as nine acres. 

Why are loons sometimes observed in large gatherings during the summer? This is a social preparation for migration. 

What do loons eat? Loons feed primarily on fish, frogs, crayfish, mussels, leeches and aquatic insects. By the end of summer the young fledglings are capable of feeding themselves. 

Why are loons observed running across the water? Because of their large size and weight, loons require about 1/4 mile of lake surface to become airborne and thus appear to run across the water before taking off.

Are loons strong fliers? Once airborne, loons are powerful fliers. Pilots have clocked them flying at speeds up to 80 mph. 

How do mates locate each other? It is assumed that loons return to the same lake every year.  Males claim the same territory and await the female’s return.

Why do loons make so many weird calls? Loon calls have been identified into four classifications: Wail, Tremolo, yodel and hoot.

  • The wail is perhaps the call most frequently heard.  A loon will wail when it becomes separated from the chick or if its mate fails to return. 
  • The tremolo is an aggressive response given when disturbed by a boater or predator. 
  • The yodel is also an expression of aggression and is given by the male during a confrontation.
  • The hoot symbolizes a call of curiosity and/or happiness.
The sounds are apparently a learned communication between the birds. To hear the richness of their harmonics is clearly a unique experience. 

Why do loons sometimes stand up on the water with their wings extended? Loons rise up on the water to preen themselves, to stretch their wings or to dry their wings after a drive. 

When approached, why do loons sometimes stand up on the water with their wings tacked to their sides, like penguins? The “penguin dance” is a sign of extreme agitation.  This behavior symbolizes that the loon’s territory has been violated.  The penguin dance is generally combined with frantic calls and is one of the last defense actions
available to loons.  Anyone observing such a response should retreat immediately. 

Loons in Mercer, WisconsinWhy do chicks ride on their parents backs? With their young on their backs, the adult loon can provide better protection from predators both above and beneath the waters surface.  This is an opportunity for the young to conserve energy and body heat. 


Do loons mate for life? Loons are believed to mate for life, but more research is needed in this area. 

Do loons have a courtship ritual? Yes, Courtship consists mainly of head dipping and shallow dives. In spring, loons are frequently observed chasing each other across the surface of a lake; this is primarily territorial behavior not courtship ritual. 

What does a loon nest look like? The nest consists of reeds, sticks, grasses and muddy vegetation from the bottom of the lakes.  This material is loosely formed in the shape of a mound, roughly 1.5 feet in diameter, with a slight hollow in the middle.  Both the male and female participate in nest building which is completed by mid-May. 

Where do loons construct their nests? Because of their difficulty moving about the land, loons build their nests within a few inches of water. When a nesting loon is disturbed, it slips off the nest and submerges to keep the location of its nest unknown. 

How many eggs does the female lay? Soon after construction of the nest, the female lays two eggs. 

What size and color are loon eggs? Loon eggs are roughly 3 1/2 by 2 1/4 in size with a thick shell and are olive green color speckled with brown spots. 

How long do loons live? The common loon may live twenty years or more. 


(This page was taken from the Mercer, Wisconsin web site

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