Loon Project of the Northern Midwest
By Walter Piper, Professor of Biology, Schmid College of Science and Technology
Chapman University, Orange, CA 92866 | Loonproject.org
Loons, as you probably know, are one of the most loved animals across most of the northern part of North America. Their haunting, human-like calls echo across northern lakes, especially at night, and have come to epitomize the northern wilderness. Loons, being a crucial part of the aquatic ecosystem, are "sentinels" for water quality.
Where loon populations are suffering, we are also seeing declines in water quality, which means that human recreational activity like fishing and boating is impacted.
Loons need a runway for takeoff — from 30 yards up to a quarter-mile (depending on the wind) — for flapping their wings and running across the top of the water in order to gain enough speed for lift-off. Photo credit: Linda Grenzer
Loon populations in the Upper Midwest of the United States and into Ontario, Canada are in trouble. In Wisconsin, where we have been conducting a detailed long-term study, we’ve seen a 22% decline in the population in less than 3 decades! Based on our population estimates, loon numbers are decreasing by 6% annually – a shockingly high number that means that lakes on which many vacationers have always heard loons are now falling silent.
Since learning of loon population declines two years ago, we have been investigating the causes of the declines in Wisconsin. Just this year we’ve found that the physical condition of both chicks and adults there is strongly related to water clarity. Clear water gives good visibility for chasing fish, which means that adults can find food for their chicks; murky water makes foraging difficult, resulting in less food for chicks and their parents. We are following up on these findings now, but we already know that loss of water clarity threatens loons in Wisconsin.
The likely reasons for Wisconsin’s decline in water clarity are:
Excessive fertilizer, pet, and human waste that gets washed into lakes by rainfall and causes increases in phytoplankton
Increased rainfall related to climate change, which exacerbates #1
increased boat traffic near loon families, which – our evidence shows – impairs foraging of loon families, contributing to mass decline.
Once we nail down that water clarity is indeed the issue, we can make recommendations for how lake residents might reduce harmful phosphorus and nitrogen inputs into lakes, which boosts phytoplankton to make water less clear. If human recreation turns out to be contributing to the loon decline, we can explore new rules restricting disturbance of loon families.
Loons are water birds, typically coming ashore only to mate and incubate eggs. Loon parents and their 2 chicks can eat about a half-ton of fish over a 15-week period. Photo credit: Linda Grenzer
If we can confirm and understand what is hurting our loon populations in the Upper Midwest – and halt the current breeding decline there – we will likely be able to anticipate problems arising in Canada and help take steps to protect against population decrease there as well. Although there is evidence that loons are declining in central Canada, our most immediate concern is the decline of loons in the upper Midwest (MN, WI and MI), which is the heart of loon country in the United States.
Of course, we hope to conserve loons in the Upper Midwest, not merely document that the population there is in decline. We have begun to work with local water quality experts to pinpoint factors that are causing the reduction in water clarity that is hurting loons. Our hope is that we can then recommend changes in treatment of shorelines and water sources that can curtail the problem.
Focus on Loon Conservation and Expansion into Minnesota
In 2023 and subsequent years, our goal is to continue building a brand new study population in Minnesota. Our plan in Minnesota is to learn whether chicks and adults there are suffering from water-clarity-related declines similar to those in Wisconsin. If so, this would tell us that water clarity is a regional problem for loon populations in the Upper Midwest, not just a local problem confined to Wisconsin.
How our study to track the loon population in north-central Minnesota has progressed:
In 2021 and 2022, we marked loons intensively near the town of Crosslake, and we now have members of breeding pairs marked on 57 territories.
Continued marking and measurement of breeding success in the new Minnesota Study Area in 2023 and 2024 should allow us to expand our marked population to 105 breeding pairs and produce an assessment of the MN loon population by 2025. (Naturally, next steps in Minnesota will be dictated by whether we discover that the population there is stable, declining, or increasing.)
We are currently raising funds to support our building of the Minnesota Study Area. With generous donations, we will be able to complete the banding of our Minnesota study population (105 territorial breeding pairs) by 2024 and meet our deadline of a population assessment by 2025.
This map shows both the Wisconsin and Minnesota study areas.
Needs for Project Funding
Our need for funding is critical. Although we acquired financial support for our work from the National Science Foundation (NSF) for 14 years, a shift in programs at NSF has made long-term funding for our long-term loon study more difficult to acquire, prompting us to explore ways to continue our research using other sources of funds. That is why we are now asking for the public’s help.
So far, we have scraped together enough funding to “tread water” in Minnesota. That is, we can send a skeleton crew to Minnesota to measure rates of territorial return and capture and mark more loons late in the year. But current funding levels do not permit us to gather the kind of high-resolution data we need (i.e. weekly visits to each territory to measure breeding success) to meet our goal of making a population assessment of Minnesota by 2025.
We have set up a donation link on the Chapman University website for anyone willing to support this effort — every little bit helps and we are grateful for your support! DONATE HERE
Loons are very photogenic, of course, and we acquire the bulk of our photo and video content from Linda Grenzer. You can see her work and appreciate the loons in our study area via our blog posts and on Instagram @loonproject.
About Loon Project
The Loon Project is a 30-year investigation of loon behavior, ecology, and conservation in the Upper Midwest of the U.S. by Walter Piper, a professor at Chapman University (Orange, CA).
The central focus of the investigation has always been the territorial and breeding behavior of the common loon in northern Wisconsin. Maintaining a population study of 105 territorial pairs in Wisconsin, we’ve marked these birds with colored leg bands for identification and tracked them to learn more about their habits, tendencies, and lifestyle.
Over the past 3 years, we have focused attention on loon conservation after learning that our Wisconsin study population declined by 22% in the past 25 years. In 2021, we expanded our study into Minnesota because of concern that the population declines might be widespread.
Topics studied:
POPULATION & REPRODUCTION:
Changes in genetic parentage of loon chicks
Do loons mate for life?
In what ways has the loon population in northern Wisconsin declined?
Rapid aging of male and female loons
HABITAT:
Negative impacts of black flies on loon breeding success
Which bird is choosing the nest location?
How do male and female loons benefit from long-term residency on a single territory?
How do young adults find and settle on territories?
BEHAVIORS:
Old male loons have become very vocal and aggressive in defense of their territories
Territorial aggression and fights to the death by male loons
WATER QUALITY:
How has water clarity changed in northern Wisconsin and how does that affect loons? Sadly we are finding that chicks, males, and females all weigh significantly less than they did 25 years ago!