Answers from the Experts: Loons

Answers from the Experts: Common Loons May 18, 1995

Get ready... Here are 8 pages of Questions and Answers from experts Dave Evers and Terry Daulton. Terry directs Wisconsin's LoonWatch program, and added her great knowledge about loons to this report! Dave is now heading out into the field for another summer of loon research. Just imagine how many hours of careful study it has taken to find answers to the questions you asked!

From MINNESOTA: We are students at Winona Area Learning Center.

Q. We would like to know how you catch the loons that you band.

A. Well, all the work is done by night. I use strong spotlights that are 10x brighter than your car's lights. I can only catch adults that are with chicks since I rely on their parental protective instinct. When I get close to the family I start playing calls and also give little chick peenting calls. These calls make the adults very curious as to whether the loon in front of them is friend or foe. Since we have the lights on them, they can't see we are a boat full of people, instead they need to respond to the loon calls they hear. Once we get close enough I catch them with a large fish net. The entire capture happens quickly and at a very slow speed since I basically call the loons in toward the boat. After we band and take blood and feathers we release all the loons (usually within 30 minutes after capture) back in their home. By the next day they have forgotten what had happened that night.

Q. We want to know if the loons are hunted illigally by poachers ?

A Not often, although ocassionally a loon will be shot mistakenly (as a duck).

Q. Do loons migrate in large groups like geese, or do they migrate alone?

A. THey do not migrate in flocks but singly or in loose groupings.

Q. Do loons ever stop in Winona, MN? If so, when?

A. Loons would come through Winona shortly after ice out, in April.

Winona Area Learning Center

From MINNESOTA: Hi David, People at Cloquet High School want to know:

Q. Does the mercury in lakes ever "go away?" Can it "settle out" to the bottom of lakes and lie undisturbed, or must it forever be part of the food chain, ending up in fish and loons?

A. Mercury can settle out into bottom sediments and become less available to the food chain. In contrast, if lakes become acidic mercury that's in the bottom sediments can actually be disolved into the water.

Q. What methods are available to remove mercury from lakes?

A. There are no current methods used on lakes.

Q. How deep do adult loons dive to find fish?

A. O average, loons dive for 42.6 seconds. On small, clear lakes with good fish populations, dives are shorter. On acid lakes, dives are somewhat longer because there are generally less fish.

Q. How deep have baby loons been found?

A. Loon chicks do not truly dive until 8 days old. At that time they can dive on average for 30 seconds.

Q. Will mercury be passed by an adult to the eggs? Does it have an effect like that of DDT on eagle eggs?

A. Yes, the mercury is passed on to the egg, and the chick will have higher levels. The effect is not eggshell thinning, as with DDT, but is lack of motor coordination in chicks because the mercury affects their nervous system.

Q. Does intake of mercury cause loons to live shorter lives? What are their normal life spans?

A. Loons have reproductive FAILURE if they eat fish with higher than .4 parts per million. Reproduction is impaired when the fish have .3 parts per million. (Reproductive failure means the young do not survive.)

Q. Is there a difference in the amount of mercury that a loon takes in while living in its northern range (i.e. Minnesota) versus its winter range?

A. We have very little data on mercury uptake in wintering areas. Uptake in Minnesota can vary depending on the lake chemistry. Lakes in Northeast Minnesota have high mercury.

Q. What could we expect to learn about the kind and amount of food that a loon eats just before migration--does it "stock up" on fish that might have more mercury in them at these times, or is the summer loon forage a higher source of mercury?

A. We believe that fish eaten in the summer are the problem. Here's why: Feathers can be tested for mercury, and feathers that have grown during the wintertime (on the wintering grounds, before migration) do not seem to contain high levels.

Q. What kinds and sizes of fish are the worst sources of mercury for loons?

A. Larger fish are worse because they concentrate the mercury since they are at the top of the food chain. Walleye are worse than minnows, for example.

We hope this isn't too many questions; we're very interested here about loons. They seem to symbolize a good environment. Our pride in our region shows when we point out loons and their songs to visitors. It's as though by having loons, our part of the country is extra special.

Sincerely, Rick Schroeder Cloquet High School

From MINNESOTA: Dear Mr. Evers: We are seeing loons on our lakes around Chisholm. Hoot, Hoot. We have two questions. Mr. Abraham's 5th Grade Class Chisholm, Minnesota

Q. Do loons grow larger or faster in lakes that have a fatter (more oily) prey? Example: Northern trout lakes with white fish or ciscos in them versus typical lakes with perch, chubs, and suckers.

A. I really don't have an answer for your first question. Actually, this is intriguing enough to maybe investigate in the field. Maybe I could capture chicks on lakes with 2 different prey bases and weigh the birds and take measurements of their wing feathers to determine growth rates.

Q. When do loons change from their winter plumage to the beautiful dark green-black and white? Does this take place on the coast or on their way back to the north?

A. Adult loons change into their black and white breeding plumage (or alternate plumage) from late February to late March. This happens on their ocean wintering waters just after they lose all their wing feathers in January. For the first 3 years of a loon's life it is all gray (like an adult in winter plumage). At the end of the third year, the loon molts into the better known black and white plumage for the first time. It does this in July. Every year afterwards it molts into its breeding plumage earlier and earlier until around 6-7 years of age when it molts the same time as the older adults.

From MINNESOTA: Hi, we're from Stillwater, MN and we have a couple of questions for you

Q. What is the loon's migration route South to the Pacific?

A. Generally from Alaska south along the coast. We need additional data on this area, however.

Q. What is the percentage that die on the all-around trip?

A. This is not known.

Q. Do poachers kill loons on their migration path in other states?

A. There may be occasional killings, but it is not seen as a large problem.

Q. Do loons eat exotic foods that would be hazardous to their health on their migration trip?

A. Sometimes. For example, there was a large die off of loons in Florida in the 1970's. They were mainly eating crabs which made them susceptible to a parasite. It is thought that they were eating the crabs due to elevated mercury which reduced their ability to catch fish.

Matt Looney, Robert Walker and Nathan Hiles 6th Grade Lily Lake Elemenatary 0834llel@InforMNs.k12.MN.US

From PENNSYLVANIA: I like the migration about the loons.

Q. Why do the loons stay until mid-November?

A. Loons generally stay until fall, and some will stay until ice up, even beyond November. There are some sightings of looons on inland lakes in the south in winter, so no all spend the entire winter on the coasts.

Q. Do loons like hot or cold weather?

A. Loons may not "like" or "dislike" weather, but it may make their life more challenging. For example in the summer loons may be harassed by insects which come out on warm days. cold temperatures would require that they eat more to keep the energy up.

By: Michelle Rutherford Mrs.Mcewen's class


Mr. Evers: The Biology classes at Apollo High School have the following questions for you.

Q. Why does the eye color of loons change from summer to winter?

A. We are not sure, but there are two theories: The red color may be part of the breeding plummage, or it may help with underwater vision.

Q. What is the average number of chicks raised by the female?

A. The exact answer is .77 chicks per pair, on average. If this does not make sense to you, think of it this way. All loon pairs don't successfully raise young each year. However, for every two loon pairs ther would be 1.5 chicks, and for every four pairs, three chicks would survive.

Q. What is the trend of the mercury level in loons?

A. We don't have enough data to determine a trend, but we do know that mercury is higher on acidic lakes.

Thank you very much, From: Apollo High School


Hello! We're from Pelican Rapids High School in Pelican Rapids Minnesota. Pelican Rapids is located in the northwestern part of Minnesota at 46.38 degrees Lat. and 96. 06 degrees Long. We have some questions about loons we would like you to answer. Please use above address for your answers.

Q. What species of fish do the loons feed on?

A. Many species such as: perch, crappie, walleye, ttrout. Perch is a favorite.

Q. What is the fall migration of loons leaving MN?

A. Fall migration occurs in October through November.. Adults leave first & juveniles last. There are large staging areas, with hundreds and hundreds of loons, such as at Lake Mille Lacs. (See if you can find it on a map.)

Q. How much of a runway do they need to take off? A. Usually about 1/4 mile.

Q. Where are the summer breeding grounds?

A. Generally loons nest on quiet, clear lakes where there are few huan distrubances and good nesting areas.

Q. How long do they live?

A. About 25 years, at the most.

Q. How big do they get? A. 7-10 pounds.

Q. How fast do there wings flap when they fly? A. They flap 255 times per minute!

Q. How many eggs do they lay? A. Usually 2.

Q. Do they return to the same nesting spot yearly?

A. Often they return, but not always. Sometimes they will "skip" a year.

Q. What is the reason for the loons black and white color? A. There is no clear reason.

Q. How often do the loons mate?

A. The courtship sequence takes 3-10 minutes. They usually mate during the day, not the morning or evening.

Q. Do the loons fly the whole time when they migrate, if not where do they stop over?

A. They do not fly non-stop, but rest on lakes, reservoirs and on the Great Lakes during migration.

Thank you for taking the time to answer our questions!

Yours truly, The students at Pelican Rapids High School 10 grade biology class. jcarpent@InforMNs.k12.MN.US

From: MASSACHUSETTS: Hi Mr. Evers! The fifth grade science class at Newton Country Day School in Massachusetts would like to ask you some questions about loons. Here are our questions:

Q. Are loons intelligent birds? Would they fly into traps easily? If so, why? -Christi Gannon

A. Actually Chrisi, I think all birds are intelligent, at least they are all smart enough to survive thousands and thousands of years. I think loons are more interesting than most other birds because it seems as though each one of them has an individual personality. They are very curious creatures and have a lot of time to be adventuresome. When we have them in the hand they are usually very calm and seem to accept the temporary intrusion into their life ... somehow knowing that we mean them no harm and just want to better understand their lives. Loons don't fly in traps necessarily. We catch them at night with spotlights and large hand nets.

Q. How did you get interested in studying loons? -Mary Taggart

A. Mary, my interest in loons started innocently enough while I was working as a biologist with a Nature Center. I wanted to start a research project that would make a difference and thought it would be best to work with a rare animal in the area. There were only 5 pairs of loons in my area and they were in danger of disappearing due to all the shoreline development and boating. From there it kindof ballooned into a much bigger study. It's interesting how many people become hooked on loons while working with on this project. The loons really have a way of drawing you into their world.

Q. Why did you want to study these birds and what made you want to? -Ashley Marks

A. Well Ashley, my initial interest came from a feeling of wanting to make a difference in the world. I thought that my work with a species that was rare in southern Michigan could help it surivive. I'm not sure where this feeling came from. When I was younger I did spend a lot of time outside watching nature and always curious at how it worked. As I became older I discovered a lot of the questions I had could no longer be answered because of the way we treat the Earth. So I think there was a growing feeling that I needed to do something to help stop our assault on the World or at least slow it down to where we started working with it instead of against it. Loons are an ideal species to observe since they spend all their time in the middle of a lake. How many species of birds can you watch their entire daily routine?

Q. Do you have to go to college to be able to study loon migration? If yes, how many years? Is it hard, or fun or both? -Patricia Foster

A. It does help to attend college, Patricia. A bachelor of science in ornithology or ecology will take you much farther toward a job studying something like loon migration. I only know one person that actually spends all of his time studying loon. Maybe you will be the second. It is a lot of fun to come up with a question and actually follow through with it. It takes 4 years for a B.S. degree. Nowadays you really need to go a couple more years and get a Master of Science degree to compete with all the other people that like to work with birds.

Q. What is the most common place in Massachusetts that we will find loons? -Lindsay McKenna

A. The most common places are reservoirs. These have litttle disturbance because they are protected as part of the water supply system.

Q. How did loons get their name? -Katrina Capizzi

A. "Loon" comes from the early Scandanavian word "lumme" which means clumsy. This refers to their slumsy behavior on land.

Q. How long can loons hold their breath for while they are under water? -Sarah Fallon

A. The average loon dive is about 50 seconds. They can dive for much longer, however.

Q. How long does it take for a loon to learn how to fly? -Meaghan Mackesy

A. Juvenile loons begin trying to fly at about 10 weeks and are generally able to fly by 11-12 weeks of age.

Q. How many loons are left on this earth? Where are they most likely to be? -Lauren Basile

A. There are about 400,000 common loons in North America. Most are in Ontario, Quebec and other Canadian provinces.

Q. Do you have to go to college to be able to study loon migration? If yes, how many years? Is it hard, or fun or both? -Patricia Foster

A. You can start studying loon migration in you own "backyard"! Researchers generally have 4 year college degrees, master's degrees or even a PhD.

Q. How long do common loons live? -Alli Tahmoush

A. About 25 years maximum.

Thank you very much! Fifth Grade Science at Newton Country Day NSH10ED@AOL.COM

Journey North 125 North First Street Minneapolis, Minnesota 55401 Phone: (612)339-6959