The Adirondack Center for Loon Conservation studies how well Common Loons are able to nest and raise chicks in the Adirondack Park and what gets in their way.

Since 2013, we have deployed motion-activated cameras at selected loon nests. These cameras quietly record thousands of images throughout the breeding season, allowing us to see what happens at the nest without disturbing the birds.

From over 325,000 photos over the past 13 years, we’ve learned more about loon behavior, clutch size, hatch dates, and how often nests are disturbed or preyed upon. The cameras have even revealed previously unknown threats, such as black bears raiding nests, and helped us track how stronger, more frequent storms and changing water levels affect nesting success.

This research directly guides how we protect loon nests in the Adirondacks. By sharing these images and stories with shoreline homeowners and visitors, we can show what disturbance looks like—and how giving loons space can help chicks safely hatch and thrive.

Common Loons (Gavia immer) are indicators of how air pollution impacts lakes and ponds in New York’s six-million-acre Adirondack Park.

Since 1998, ACLC and its partners have monitored the Adirondack loon population to measure exposure to mercury, a toxic pollutant that harms wildlife and people. Early research showed a clear pattern: loons with higher mercury levels have lower reproductive success than loons with low mercury exposure.

Stronger air emissions regulations, including the Clean Air Act Amendments of 1990 and the Mercury and Air Toxics Standards, have since reduced airborne mercury and acid rain, which has helped many previously acidic and mercury-laden Adirondack lakes begin to recover. As mercury and acid deposition declined across the Northeast, mercury levels in Adirondack loons leveled off after 2010 and previously acidified lakes began to recover.

Today, mercury and acid rain are no longer the primary factors limiting loon reproductive success in the region, though they remain a significant concern if emissions regulations were to be relaxed. This long-term research highlights how policy changes can improve ecosystem health—and how loons help us track the ongoing effects of environmental change.

We are seeing the impacts of climate change on breeding loon pairs in real time in the Adirondacks. More frequent torrential rainstorms can flood shoreline nests, washing away eggs and causing nest failure. Warmer winters are also changing ice patterns on Adirondack lakes. When lakes freeze later, some loons delay migration. If they are still present during their winter wing molt (when they cannot fly) and the lake suddenly freezes, they can become trapped in the ice, a growing problem known as “molt-migration mismatch.”

Climate change may also expose loons to new diseases, such as avian malaria, as warmer temperatures allow disease-carrying insects to expand their range northward. In addition, rising temperatures during nesting season could push the species’ breeding range farther north as warmer temperatures force incubating loons back into the water, reducing nest success and making the Adirondack Park, already near the southern edge of that range, an “ecological sink” in which more birds die or fail to reproduce than are replenished into the population through reproduction and immigration.

These combined pressures put the future of Adirondack loons at risk and highlight the urgent need for climate action and conservation.