Biology
The Common Loon in Michigan
The Common Loon is one of the earth’s most ancient birds, its ancestors having
originated
some 50 million years ago, and the modern Loon about 10 million years ago. The loons’ hauntingly beautiful
voice is matched by
its striking plumage, with a collar of white stripes and intricate patterns of
white and black feathers on wings and back.
The loon wanders endlessly. It summers on northern lakes and migrates in a
perilous journey to the seacoast each fall. Its return to familiar northern
lakes signals the end of a long winter. To many, the Common Loon is
wilderness, and beckons us to recall when life was simpler. To hear the loon as
we stir in the early morning light soothes the soul.
The loon is most at home on the water. Its legs and large, webbed feet are
set far back on the body, providing excellent propulsion underwater, but making
it difficult for the bird to walk on land. Its solid, rather than typically
avian hollow bones make it an excellent Diver-its name in the old world. Its
heavy body and high wing loading require it to run, and then fly along the water
for hundreds of yards to become airborne.
Small fish are the favorite food of the loon, although they may also eat
frogs, small invertebrates, crustaceans, and aquatic plants. A loon catches and
eats its food with its spear-like bill while diving underwater. Dives can last
for several minutes, during which the bird can cover considerable distances, and
apparently vanish.
The nest is always constructed near water. The female usually lays two eggs.
The male and female share in incubating the eggs for about 28 days, and the nest
is defended vigorously during incubation. The downy, black chicks leave the nest
soon after they hatch and depend on the adults for food for about eight weeks.
The young loon often rides "piggyback" on a parent, finding warmth,
safety and security atop the more experienced bird. They soon learn to fish, and
in the fall migrate alone to the sea, where they remain for three years until
they too return to their natal lake or nearby to raise another generation of
loon chicks. A loon may live as long as 20-30 years.
Common Loon populations in the United States have receded northward since the
advent of European settlement. Their range in the modern age finds them along
the northern tier of the continental US, in Canada and Alaska. At the
turn-of-the-century, Michigan Loons continued to breed throughout the state,
although southern nesting populations were declining. Now the majority of
breeding loons is restricted to Northern Michigan, and the Common Loon is,
unfortunately, anything but common here.
Threats to Loons-Natural and Man Made
§ Loss of nesting habitat due to lakeshore development
for homes, recreation, or campsites.
§ An increased number of humans on lakes.
§ Noise and disturbance from boats and personal
watercraft. Chasing loons, swamping nests with excess wake, washing eggs out of
the nest, or running over chicks or adults.
§ Getting too close to the nest or Loon family with a
boat or canoe.
§ Water quality changes that occur from septic
systems, acid rain, and mercury contamination.
§ Water level fluctuation with resultant flooding of
nests, or stranding the nesting adults too far from rapid escape to the water.
§ Entrapment and drowning in fishing nets on the Great
Lakes and oceans.
§ Accidentally landing on wet roads and parking lots,
which appear as open water. The heavy bird is easily injured by its own weight,
and may become infected and die.
§ Becoming ice bound by early winter ice. Birds can
quickly become hypothermic and perish.
§ Lead sinkers and fishing line causing injury,
entanglement, illness, and/or death.
§ Increase in predators such as eagles, mink, otters,
ravens, raccoons, and gulls; the latter two often caused by an increase in
population and garbage.
§ Competition from exotic and aggressive Mute
Swans.
§ Botulism infections may occur in periodic epidemics
with hundreds of loons dying on the Great Lakes.
§ Decrease in fish supply or other food due to over
fishing or contamination of water. A visual predator, the loon needs clear,
clean water to catch its prey.
Let’s Get the Lead Out
Every year, loons, swans, cranes, and other water birds die needlessly from
lead poisoning after swallowing lead fishing sinkers and jigs.
Sport anglers attach lead weights to fishing lines to sink hook, bait, or
lures into the water. Some anglers use lead-weighted hooks, called jigs. A
sinker or jig may accidentally detach from a line and fall into the water, or
the hook or line may become entangled and the line may break or be cut.
A fish eating water bird, like a Loon, may be attracted to bait on a hook. It
may swallow a sinker or jig attached to the line or to an escaped fish.
Lead poisoning is not a small problem. Between 1.5 and 2.5 million migratory
waterfowl die annually from consuming sinkers, jigs, or shot made from lead.
This is two to three percent of the entire North American waterfall population.
Lead poisoning
A bird that eats lead will become ill and die. Ingested lead enters the
gizzard, where a combination of stomach acids and abrasion breaks down the
metal. It then is absorbed into bloodstream.
A bird with lead poisoning will exhibit physical and behavioral changes
including loss of balance, gasping, tremors, and an impaired ability to fly. The
weakened bird is more vulnerable to predators, or it may have trouble feeding,
mating, nesting, and caring for its young. It becomes emaciated and often dies
within two or three weeks after eating the lead.
Just one lead sinker or jig can poison a water bird. On freshwater lakes of
the eastern United States and Canada, lead poisoning is the most significant
contributor to death in adult Common loons, causing at least 50 percent of known
deaths.
Safer Fishing Tackle
Lead poisoning does not have to happen. Sinkers and jigs do not have to be
made of lead. Many alternatives to lead fishing weights are available, and they
are both inexpensive and ecologically sound.
Anglers can use sinkers and jigs made from nonpoisonous material such as tin,
bismuth, steel, and recycled glass.
The MLPA has developed an educational brochure
for Michigan anglers to help them understand this problem.
New Regulations
To help prevent water birds from getting lead poisoning, Great Britain banned
the use of lead sinkers in 1987. In Canada, it is illegal to use lead fishing
sinkers and jigs in national parks and national wildlife areas. The U.S. Fish
and Wildlife Service is currently considering banning the use of lead sinkers
and jigs on national wildlife refuges. Several states will likewise soon ban the
use of lead.
Mercury Poisoning
Mercury poisoning is becoming a major problem for loons. Eating contaminated
fish and plants has caused mercury levels to become very high in some loons.
Because they are at the top of the food chain, tiny amounts of mercury from
sources such as automobiles, coal-fired power plants, and industrial pollution
are magnified in the fish consuming loons. Organic mercury, a neurotoxin,
affects behavior; affected adults parent inadequately, giving chicks less back
riding, providing insufficient food, leaving the chicks on their own too early,
and becoming weak and listless. A good summary of the effects of mercury on
humans and wildlife is reported in the 1995
Proceedings of the Canadian Mercury Network Workshop.
How to Help Loons and People Coexist
Though it is illegal to harass wildlife in Michigan, even more importantly,
the unintentional or intentional behaviors that result in the loss of even one
chick press this never Common species closer to disappearing from Michigan
waters forever. The Common Loon does not breed for the first three to four years
of its life. Usually laying only two eggs per year, average nesting success is
less than one chick per pair per year. There are probably less than 400 pairs
breeding in the state of Michigan. Each chick is precious, and the loss of even
a single chick threatens the species survival as a whole. The numbers of threats
to the loon are many and increasing.
During the past several years there been increasing numbers of reports of
loons abandoning their nests, being frightened from lakes, or even being injured
or killed by encounters with personal watercraft or high-speed
boats. Personal
watercraft can easily enter the shallow coves that are favored by nesting loons.
The terrified loons may abandon the nest and never be seen again following a
single, brief encounter. More than a 6-inch wake can in minutes swamp the nest
and result in loss of the eggs. The timid loons don’t easily tolerate close
disturbances from curious onlookers in boats and canoes, and a Loon frightened
from its nest exposes the eggs to predators that constantly watch for
opportunity, or exposes the eggs to the baking hot sun.
With a little understanding and care from humans, loons and people can share
the lakes. Loons have lived on these lakes for thousands of years. If humans
stay back and watch loons from afar, both can do well. Loons can tolerate boats
to within about 100 yards. Their natural curiosity may bring them closer if you’re
lucky. Avoid approaching them directly and give them space. Most importantly,
avoid nesting areas or artificial nesting islands marked with buoys.
If you see people harassing loons, report them to the Department of Natural
Resources, or your local sheriff. Watercraft registration numbers are essential,
and videotaping may make prosecution and conviction of such individuals more
likely.
Your lake association and DNR or conservation group can monitor lake water
for toxins. Keep a portion of your lake free from development, especially if you
know the location of the nesting area. Keep boats and personal watercraft in
good working order to avoid oil discharges into the water.
Join the Michigan Loon Preservation Association to keep updated on recent
Loon statistics, behavior, numbers, and to support research. The MLPA is a
non-profit, Michigan Audubon Society affiliate established over ten years ago.
Please write
to us at: Michigan Loon Preservation Association, c/o Michigan Audubon Society,
6011 West St Joseph Highway, Suite 403, Lansing, Michigan, 48917.

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