Over the course of any given year, our loon biologists field a lot of questions about loon biology, behavior, and migration patterns. As we prepare for the 40th Annual Loon Count in 2023, we wanted to share answers to some of the most Frequently Asked Questions!
Do loons return to the same lake year after year, and nest in the same place every year?
Once a chick fledges and migrates to the coast for its first winter, it won’t return to lake breeding grounds until it’s two to five years old. Then it may wander between lakes over a few breeding seasons before settling on a lake to breed—either the same lake where it was raised as a chick or one within a dozen miles of its natal lake. Once settled on a breeding territory, loons show high site fidelity—returning to the same lake each spring, year after year. Loons typically stick with the breeding territory until they lose to a challenger. Loons will also use the same nesting site repeatedly, though may move to a new nesting site within their territory if, for instance, they’ve had low success at a site or the habitat has changed.
Do loons mate for life?
No, pair bonds last, on average, six to seven years. Pairs often change when a loon challenger takes over a territory or a mate doesn’t return to the territory after the winter. Therefore, loons can be said to engage in serial monogamy.
Loons start to breed when they are about six years old. Once they have a territory and a mate, loons can potentially produce one brood of chicks per year. Typically, they lay one to two eggs at a time and both parents incubate the eggs for about a month. Loons can re-nest if their first nest isn’t successful, but they won’t produce more than a single brood in a season. On average, loon pairs successfully hatch and fledge one chick every other year.
How long do loons live?
Most common loons live to be about 20, but some die before then, and some live longer, with one documented at 35 years old!
Where do Maine loons go in the winter?
Because our lakes freeze, Common Loons normally migrate in late fall to salty waters including coastal bays and coves, the mouths of coastal rivers, and sometimes even areas up to 60 miles offshore in New England’s coastal waters. Adults leave before juveniles and both will often gather in social groups before making their way to wintering grounds. Loons that breed on Maine’s lakes often don’t migrate very far, even overwintering right off the coast of Maine. Some of Maine’s breeding loons do travel farther south, however, to overwintering sites in New Jersey, Maryland, and beyond. Wherever they travel, most will return to the same four to eight square mile area every winter.
How do they adapt to being in a saltwater environment in winter?
Loons likely do not drink saltwater. However, they do have a salt gland above the eye that helps get rid of excess salt they ingest from feeding on marine fish, crabs, and other marine organisms.
Is flooding from boat wakes a threat to loon nesting success and chick survival?
Because loons feet are located far back on their bodies, loons can’t walk on land. As a result, they nest right on the shoreline, which makes their nests vulnerable to flooding by boat wakes. Eggs can also be washed out of a nest by boat wakes. Every year people report eggs off the nest and floating in the water. Wakes are the most likely cause, although loons can sometimes knock their eggs into the water if they are alarmed and leave the nest quickly. To protect shorelines from erosion, all boaters in Maine are required to travel at headway speeds (non-wake-producing speeds) within 200 feet of shore or islands. This law helps protect wildlife from disturbance and loon nests from boat wakes. However, a recent study looking at a new type of motorcraft known as a wake boat or ballast boat, which produces a wake large enough to surf behind, found that a 500 foot distance from shore may be necessary to protect property and wildlife from these larger wakes.
What is the present situation with loons and lead poisoning and has the lead tackle law helped?
Based on many years of data on causes of loon deaths in Maine, it appears that the number of lead poisoned loons is going down as a result of legal restrictions on the use and sale of certain sizes and weights of fishing tackle. Public outreach about lead poisoning from lead tackle and opportunities to turn in lead tackle have also contributed to the reduction in loon deaths from lead tackle. Yet, lead poisoning continues to be one of the leading causes of death for Common Loon adults in Maine. Additional steps and cooperation are needed to get lead out of tackle boxes and to curb the use of lead tackle purchased in other states and brought into Maine. Also, painted lead jigs are still legal in Maine even though paint does not protect loons from lead poisoning if ingested, and sometimes the paints themselves contain lead. Tackle that is heavier or larger than the current restrictions can also contain lead and other metals like zinc and cadmium, which, while legal to use, are also toxic to loons.
Are bald eagles becoming a threat to the loon population?
Eagles are a top predator and loon chicks can be an easy prey item. However, Common Loons and Bald Eagles have coexisted across the same North American range for many thousands of years. With more eagles all across Maine, loons may be adapting by improving their defensive tactics. For example, Common Loon adults have been seen protecting their chicks from eagle predation, and one eagle was even killed by a loon several years ago when the eagle tried to attack the loon on the nest. When you see an eagle harassing a loon, try to remember – the eagle recovery is a conservation success story and they need to eat too!
We’re seeing more loons getting trapped when lakes freeze. Why does this happen and how can we help loons stuck on frozen ponds and lakes?
Loons need a long ‘runway’ to be able to take flight. When lakes start to freeze, it reduces the area of open water and they can get stuck. Loons might stick around too long because they are either injured or otherwise unfit for the journey or hatched late and weren’t ready to make the journey before ice formed. Sometimes fully healthy loons simply stay too long, possibly lulled by a warm fall. If they begin a molt that normally takes place once they reach their wintering area, they can be caught flightless when the ice closes in.
Winter loon rescues are dangerous and take special equipment and training. Maine has not had the expertise to undertake this in the past, however, the Biodiversity Research Institute began coordinating ice rescues in 2021 and worked with several fire departments to aid in these rescues. If you find a loon stranded in ice, do not attempt to rescue it yourself; instead please call the Biodiversity Research Institute (207-839-7600) for help and let Maine Audubon know as well by emailing firstname.lastname@example.org.
The answers provided here include input from our loon biologists at Maine Audubon, as well as responses given over the years by our loon partners at Maine Department of Inland Fisheries and Wildlife, Tufts Veterinary Clinic, St. Joseph’s College, Maine Lakes, Biodiversity Research Institute, the Loon Preservation Committee and Vermont Center for Ecostudies.