MIDDLEBURY, Conn. — It was about 10 degrees outside, a few minutes before sunrise, when 63-year-old Tom Zissu pulled his 2005 Toyota Camry into a dormant amusement park along Lake Quassapaug. A biting wind made it feel much colder.

Zissu drove past colorful rides dusted with snow, past booths covered with tarps and plywood. He parked near the lake edge and pulled out a small pair of binoculars. Much of the lake was frozen, but there was still a large patch of open water a few hundred yards offshore. Zissu scanned for bald eagles around the edge. There were only crows and Canada geese.

Zissu is one of dozens of volunteers across Connecticut who braved freezing temperatures to conduct the annual mid-winter bald eagle survey. The survey is conducted simultaneously across the lower 48 states. The idea is for everyone to head out at the same time on the same day each year, providing a good relative measure of the eagle population, along with collecting important habitat data.

“It’s going on across the state, this watch right now,” Zissu said. “There’s people all over, on the Housatonic (River), on the Connecticut River, on the Thames River and some other major reservoirs and things – wherever there’s open water. It requires a lot of manpower and they couldn’t afford that, so they have the volunteers help them.”

After about 20 minutes, Zissu headed back to his car to warm up. Then he stepped back outside to scan the lake again. He remained along the lake shore for another four hours, repeating the procedure.

NOT A HOTSPOT

Zissu, of Woodbury, didn’t spot any eagles. Quassapaug isn’t a hotspot. He has spotted one or two eagles in each of the past couple of years. He’s a regular volunteer for the Connecticut Department of Energy and Environmental Protection, having gone through one of its “master wildlife conservationist” programs.

Connecticut’s eagle population gets a significant bump every winter, as northern birds leave behind frozen lakes and rivers and head south to find open water. Bald eagle numbers have soared across the state in the past few decades, thanks to conservation efforts.

“When I started, we were excited by counts of 25 birds,” said Jenny Dickson, a wildlife biologist who has worked for the state for about 25 years. “Now, we are getting to the point where we are getting hundreds of birds. That really tells us we have come a long way with conservation.”

The midwinter survey found 108 eagles in 2010, then 104 birds the following year, then 93, 107 and finally 143 eagles in 2014. In 1986, the oldest data available online, 23 eagles were counted.

The information gathered not only shows the health of the population, but also highlights areas that need protection, Dickson said.

“To successfully survive winter, there are places that are very important,” Dickson said. “What can we do to make sure those areas are still protected and useful to the birds?”

STILL THREATENED IN STATE

Last year, 197 volunteers participated in the count. Organizers expected about the same number this year. The data will be collected and compiled sometime after the end of this month. Connecticut’s Department of Energy and Environmental Protection coordinates the count in Connecticut. The effort is coordinated nationally by the U.S. Army Corps of Engineers and the U.S. Geological Survey.

Bald eagles were declared endangered under the U.S. Endangered Species Act of 1973, according to DEEP’s website. The lethal pesticide DDT was banned in 1972. Government began to actively protect habitat and nests. In 1995, the U.S. Fish and Wildlife Service changed the bird’s status to “threatened” and in 2007 the eagle soared off the federal watch list entirely. Connecticut still classifies the bird as threatened. It also enjoys significant protection under the Bald Eagle and Golden Eagle Protection Act of 1940 and the Migratory Bird Treaty Act of 1918, according to DEEP.

Those protections include steep penalties for individuals who harm the birds.

For Zissu and others, seeing the birds is a thrill. He has a strong interest in wildlife and would have gone into the field himself, but he was no good at chemistry. Instead, he went into insurance, a field from which he recently retired. He has been able to pursue his passion as a volunteer, helping DEEP with counts of eagles, Canada geese and amphibians, among other efforts.

“You always get pretty excited to see an eagle,” Zissu said. “You don’t see them that often, even though there’s more now than when there was DDT.”