The Hippo


May 31, 2020








Loons: A mixed year
Contaminants continue to harm loons

By Ryan Lessard

 New Hampshire’s loon population has been rebounding, albeit slowly, over the past 40 years. But man-made threats to loon health continue to cause mortalities, including a possible chemical dump in Squam Lake that has left just one loon chick on the lake this year — the first time that’s happened since 1975, when the Loon Preservation Committee started monitoring loons. 

“One loon chick is a dismal reproductive success,” said Harry Vogel, senior biologist and executive director of the Loon Preservation Committee.
Chemical factor
The link between the chemical contaminants, first detected during a spike in chemical levels in 2005, and loon health is still uncertain, but there is a strong correlation with the die-off of birds in the lake. 
This year, several of the birds, which are listed as a threatened species and protected by state and federal laws from hunting and harassment, failed to return to Squam Lake. Vogel said they suspect the birds died.
“It was a mixed year for loons, overall a challenging year,” Vogel said.
While in most parts of the state populations increased, Squam Lake saw a decrease. One of the biggest threats to loons is lead fishing tackle, which poisons the birds when they scoop it up and swallow it, but the problems in Squam are from different contaminants.
Vogel said since 2005 there have been relatively high concentrations of PCBs, DDTs, PBDEs, PFOA and PFOS detected in the loon eggs in Squam Lake, especially in the northern part of the lake. PCBs were once in an oil product used to keep the dust down on dirt roads and DDTs were used in insecticides. Both were banned from use nationwide in the 1970s because of harmful health effects on humans and the environment. PBDE is a flame retardant and PFOA and PFOS are used in making Teflon and similar materials. 
Between 2004 and 2005, about 44 percent of the loon population in Squam Lake died.
“We’ve never seen close to half the loon pairs on a single lake be wiped out in a single year,” Vogel said.
From 2005 to 2007, loon eggs in the lake had the highest concentrations of those chemicals, about two to nine times higher than those tested on other New Hampshire lakes. While levels have gone down, they’re still higher than elsewhere in the state.
Earlier this year, the Loon Preservation Committee submitted a report to state regulators regarding some detective work the committee did on the source of some of the chemicals. By testing crayfish, they were able to confirm that concentrations were higher in the northern parts of the lake. Then, by testing sediment, they could trace the PCBs to one tributary and DDTs to two other tributaries. The PCBs may have come old chemicals on old logging roads getting washed into the lake by storms, Vogel said. But the DDTs were either dumped intentionally into the watershed or an old barrel hidden in the forest could have rusted through, releasing the poisonous chemicals like a time-bomb. It could have taken a few years for rainwater to deliver them to the lake and another couple years for the chemicals to move up the aquatic food chain and end up accumulating in the loons. 
As for the PFOA and PFOS, Vogel said they’ve ruled out atmospheric deposition.  While they have yet to pinpoint the source, Vogel is fairly sure the chemicals were dumped or spilled at a specific location.
The committee is meeting with the state Department of Environmental Services, New Hampshire Fish and Game and the Department of Health and Human Services in the coming weeks to discuss ways to mitigate or clean up the contamination.
Lead tackle
The issue of loons swallowing lead jigs and weights used in fishing has been well-documented since the 1980s, Vogel said. Recent legislation has helped to tamp that down a bit. In June 2016, the use of lead tackle weighing one ounce or less was banned. But people are still using them. There are four known loon deaths this year from lead tackle plus a fifth “highly probable” case pending confirmation.
And these are not old jigs the birds are digging up, Vogel said. He said if the problem were ever-present, we’d see deaths throughout the season starting in April, but they always start in June and July, when humans start to go fishing. Plus, given enough time, lead tends to sink into the sediment.
The perfect storm
The metal and chemical contaminants are part of a perfect storm of factors that have been causing problems for loons in New Hampshire for decades.  
This year was especially difficult for loons; this spring was the fourth-wettest in the past 100 years for New Hampshire, and a number of storm events washed out loon nests.
Statewide, there was a slight growth in the population with a few pairs gained, according to preliminary numbers. 
“The bad news is we’re still probably only halfway toward a recovered loon population,” Vogel said. 

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