Squam Lake: A Case Study in Loon Preservation
- Jun 13
- 4 min read
Fifty years of data reveals a warning for us all
On a still summer morning on Squam Lake, the sound arrives before anything else: a long, wavering wail. It is unmistakably the Common Loon —one of North America's most ancient and recognizable birds. With its jet-black head, dagger-sharp bill, and boldly checkered back, the loon carries an air of prehistoric authority.
Squam Lake, nestled among the foothills of central New Hampshire and made famous by the film On Golden Pond, has been home to loons since long before cameras arrived. It has also been home, since 1975, to the Loon Preservation Committee (LPC). For nearly five decades, LPC has monitored, studied, and fought for loons across New Hampshire, and nowhere has that work been more urgent — or more instructive — than on Squam itself.
A Perfect Storm
For much of the late 20th century, Squam's loon population appeared to be recovering. In the mid-1990s and early 2000s, the lake averaged 14 pairs of adult loons and roughly 10 chicks hatched each season. In the banner year of 2003, fifteen chicks fledged. There was every reason for optimism.
Then, between the fall of 2004 and the spring of 2005, something went terribly wrong. In a single year, Squam's paired loon population fell by 44 percent — from 16 pairs to just 9. It was, according to LPC, the largest single-year decline ever recorded on a large lake in the organization's history. In 2007, only a single chick was hatched on the entire lake.
LPC researchers, including biologists Tiffany Grade and John Cooley, Jr., began piecing together the cause. When they submitted unhatched loon eggs for contaminant analysis, the results were alarming: Squam's eggs contained an "alphabet soup" of toxic compounds — PCBs, PBDEs (flame retardants), PFAS ("forever chemicals"), DDT and its breakdown products, and dioxins — at levels up to six times higher than eggs collected from other New Hampshire lakes. Isotope testing confirmed the contaminants came from within the lake itself, not from the loons' ocean wintering grounds.
Further sediment sampling found three specific contamination hotspots in Squam's tributaries: one site registered PCB levels 2,900 times above background levels. These findings were shared with the New Hampshire Department of Environmental Services, which in early 2020 issued new, more restrictive fish consumption guidelines for Squam Lake based on elevated PCBs. The loons had, in effect, served as the canary in the coal mine — or, as Grade and Cooley put it, as "an indicator species not just for the health of the aquatic environment and other wildlife, but for people as well."
Complicating the chemical crisis was another killer: lead fishing tackle. A single lead split-shot sinker, once swallowed, will kill a loon within two to four weeks. New Hampshire banned the sale and use of small lead jigs and sinkers in 2016, and LPC's lead tackle buyback program at loonsafe.org continues to remove the hazard from circulation.
Social Chaos and Slow Recovery
The population collapse triggered a subtler crisis. Loons are long-lived (25 to 30 years) and deeply territorial. When so many established pairs vanished from Squam, new birds — so-called "floaters" from other lakes — moved in to fill the vacuum. Constant territorial battles that disrupted incubation, caused nest abandonment, and sometimes led to the deaths of chicks. The lake's productivity remained well below the statewide average for years afterward.
Recovery has been slow and deliberate. LPC's signature tool is the artificial nest raft — a floating platform that mimics a natural island nest, buffering loons from predators and water-level fluctuations. First deployed on Squam in 1977, rafts now operate on more than 100 New Hampshire lakes and, on average, account for roughly a fifth of all loon chicks hatched in the state each year.
Photo credit: Kittie Wilson.
Where Things Stand Today
The most recent data from LPC's Squam Lake Loon Initiative offers cautious encouragement. In 2025, Squam hosted 15 territorial pairs, with 7 chicks hatched and 5 successfully fledged — a modest but meaningful output monitored by LPC's full-time Squam Lakes Biologist, Tiffany Grade. And in what may be the most tangible sign of progress, only a single loon death from lead poisoning was recorded statewide that year — evidence that the buyback program and legal restrictions are working.
Squam Lake, then, is both warning and inspiration. It is the place where the crisis was sharpest and where, year by year, the work of recovery continues — one raft, one egg, one haunting call at a time.
NOTE: Tiffany Grade will be our guide on Squam Lake for our upcoming Field Trip: Exploring Birdlife in the Squam Lakes Region
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