Common Loons On Rattlesnake Lake and Chester Morse Lake

Breeding Grounds

• Lakes and ponds
• One brood per season

Courting and territorial rituals

• Bill dipping, splash diving or surface diving followed by search swimming and inviting
• “Penguin dancing” birds raise up into a vertical position with wings spread
• Yodel calls signal territorial ownership

Nests

• On aquatic vegetation at the edge of shallow water which can be a problem when the lake has a fluctuating level.
• Nests built by male and female.
• The loon has legs set very far back on their bodies so walking on land is almost impossible hence, they build a platform-type nest big enough for the bird to land on with or without a depression to hold eggs.

Eggs

• Colored olive brown/green with black or brown markings
• Eggs are about 3" in diameter
• Usually 1-2 eggs per brood
• Most common mating system is monogamous for one season - one male mates with one female

Incubation

• Both parents incubate eggs
• 26-31 days incubation period to hatching
• Young are mobile at hatching but remain at nest and swim to nursery pools for feedings
• Flying from nest happens 75-80 days after hatching
• Young are tended by both parents

Food

• During the breeding season they feed at a “nursery pool” located some distance from the nest.
• They eat small fish and aquatic invertebrates like snails, shrimp or crayfish
• Food is pursued and swallowed underwater

Young

• Incubation occurs as the eggs are laid resulting in asynchronous hatching. This draws the hatching period out over several hours or days
• Downy chicks ride on the backs of swimming parents
• Learn to swim after two days

Conservation Issues

• Loss of nesting habit
• Acid rain threatens lake fish used as food
• Boaters scaring birds from nests leaving the eggs vulnerable to predators
• Loons will use artificial platforms

Other Interesting Information

• Loon nursery pools are where they feed. They are located at water’s edge where the lake bottom drop off in steep enough to allow underwater arrival and departure for adults. Water should be clear to spot their prey yet shallow enough to limit the size of predators. There needs to be a rich food supply to feed chicks for 11 weeks. Chicks swim to the nursery pool two days after hatching.
• Young chicks are transported on the backs of their parent. They use their bills to clamp down on the feathers of the transporter. This way they can ride down underwater as well as on the water surface.

By Susan Rafanelli ­ Education Center Volunteer