MOULTONBOROUGH, N.H. — Even with bare branches still anticipating winter snow, the landscape of New Hampshire’s lake region holds an estimable, eerie beauty.

Along with foliage, this time of year also sees an absence of one of New England's beloved waterfowl that is a haunting fixture along lakeshores.

This time of year, common loons leave their lake homes before they freeze to bob and fish in the warmer waters of the Atlantic Ocean. While they may be at their most elusive in the winter, there’s a group trying to prevent the beloved bird from disappearing altogether at the hands of an invisible enemy.

"These contaminants are ubiquitous and they're persistent and it makes one shudder to think what might all be out there that just hasn't been identified," said Tiffany Grade, a biologist at the Loon Preservation Committee.

Grade has been tracking a disturbing decline in the birds' population since the mid-2000s. Ever since, they’ve been testing no longer viable eggs in look nests on local lakes and what her team has discovered is a disastrous chemical cocktail lurking in the egg, including banned chemicals DDT and PCB.

"Here we are decades after the fact, and these are still showing up in these sediments. They're flushing into the lake and we're seeing them potentially impacting our loon population," said Grade.

DDT was a pesticide used heavily in the 1940s and 1950s in orchards. PCB was used in everything from electrical equipment to fluids for vehicles to sprays to keep the dust down in the summer on country roads. Both have been banned since the 1970s.

It’s not just the loon population in New Hampshire that these “legacy chemicals” have been found in, but in wildlife around the country and world – such as marine life up and down the east coast as well as waterfowl on the Great Lakes.

While the full extent of how these chemicals are impacting animals is still being studied, it’s been found that they can stunt growth, weaken eggshells, reduce reproduction and compromise immune function.

"This is not just the New Hampshire issue. This is a, this is a issue across the country," said Grade. "We just need more information to help us understand. You know where these areas of contaminants are both for the sake of protecting loons, other wildlife, but people as well."

The Loon Preservation Committee may be a small nonprofit, but they’re the one agency in the state who’s systematically testing species high up on the food chain measuring the impacts of these banned chemicals, which is an expensive endeavor. Grade hopes other organizations jump on board to figure out this issue not only for the sake of wildlife but for our sake, too.

"We need to make sure we understand. What the impacts potential impacts of these contaminants can be and that that's an open and transparent process," Grade said.

While this team works to figure out how to save these beautiful creatures, they also have a plea about watching what we release into our revered landscapes, because we may never be able to take it out.

"We know we can't plead ignorance anymore about what these chemicals can do, and we really need to be careful about it," said Grade.