As rivers and lakes in northern states and Canada freeze, hundreds of bald eagles migrate south searching for open water and fishing. Late January is the peak time to observe eagles in central Illinois.

“There are numerous places I’ve observed bald eagles, many of them along the Illinois River front,” said Ken Wagner, 44, of Pekin. “Some of the places I’ve seen the eagles were on the river islands at Starved Rock State Park, dead trees at Lake Chautauqua near Havana, and I’ve also seen one near Henry, Illinois, near the bridge.”

Wagner became a nature enthusiast at a young age.

“Ever since I was a toddler, my parents have taken me to the great outdoors,” Wagner said. “We did loads of camping and nature walks. Later on in life, I became an avid fisherman. While fishing, I would observe the wildlife around the lakes and rivers: snakes, birds, turtles, butterflies, you name it. With most of my observations of eagles, they are usually sitting on bare branches, but I have also seen eagles in mid-flight. I have photos and video.”

Tom Lerczak is a natural areas preservation specialist with the Illinois Nature Preserves Commission and author of the 2011 book “Side Channels: A Collection of Nature Writing and Memoir.” According to Lerczak, eagles feed on fish including gizzard shad, which are native to and highly abundant in the Illinois River, and Asian carp, a non-native and invasive species, which has experienced a population explosion in the Illinois River in the past decade.

“Asian carp have a reputation among Illinois residents as being a notorious nuisance, but they are actually quite beneficial to the eagle population,” Lerczak said. 

Because eagles feed on fish, they are dependent on open water that does not freeze over. Lerczak said, for this reason, eagles are more likely to be found along rivers than backwater lakes. The Peoria Lock and Dam, downriver from the Shade-Lohman Bridge, has a high concentration of eagles this time of year, although there is no access point suitable for public observation. 

Mike Miller is the supervisor of environmental and interpretive services at the Peoria Park District and an active member of the Peoria Audubon Society (PAS), a chapter of the National Audubon Society. Miller named the Creve Coeur boat ramp, along Wesley Road past the Peoria Lock and Dam, as a prime location to spot eagles.

“The barge activity, fleeting, and operation, tend to keep the water warmer, even on cold winter days,” Miller said. “You can see eagles sitting on the ice or in trees, or catch them flying from point A to point B. They also like to steal food from each other, so you can definitely see some of that ‘me-first’ behavior.”

Miller also said that downtown Peoria, near the RiverPlex, allows for good public accessibility to the river, and another good opportunity to observe eagles.

Another active viewing spot, Lerczak said, is Cooper Park along Peoria Lake, just south of the McClugage Bridge in East Peoria. The Illinois River flows through the middle of lower Peoria Lake, and eagles may easily be seen by walking along the sandy lakeshore.

“I guarantee there will be eagles there flying around,” Lerczak said.

Every winter, the PAS conducts a census of eagles in the area. Last weekend, teams of volunteer counters tallied the number of adult and juvenile eagles spotted along the Illinois River between Henry and Havana. Although the numbers are not yet finalized, Miller said that between 100-110 eagles were spotted.

“Those are good numbers,” Miller said, “especially considering the cold winter weather we have been experiencing and the fact that so much water, especially the backwater lakes, is frozen.”  

Lerczak partially attributes the healthy eagle population to winter-warming trends, central Illinois has been in a winter-warming trend since the 1980s, said Lerczak. In colder winters, eagles are more concentrated, with higher numbers in a condensed, common area, Lerczak said. In warmer winters, eagles are more spread out along the river.

“I can remember when a nest was rare to find,” Lerczak said. “Now they are quite common.” Eagle nests can be spotted north of the McClugage Bridge, Miller said.

Lerczak and Miller agreed that, ideally, juvenile eagles, distinguishable by their darker plumage and very little white in their feathers, should make up one-third of the total eagle population. This year’s PAS eagle census found that approximately 30 percent of the eagle population were juveniles, Miller said.

“Low numbers of juveniles could indicate a problem with reproduction,” Lerczak said. “That was one of the first indicators that there was something harmful about [the synthetic pesticide] DDT.”

DDT became available for public sale in 1945 and was heavily promoted for agricultural and household uses. Before DDT was banned in 1972, the eagle population plummeted. DDT ultimately was discovered to negatively affect bird eggshells.

Lerczak cautions that, although the eagle population is recovering from the DDT-era, “I’d say more chemicals are being used in the environment than ever before.”

There are several precautions that inexperienced and amateur birdwatchers can take so as not to further jeopardize the local eagle population. The most important rule of etiquette is not to approach eagles or nests.

“Eagles in the wild need to conserve their energy,” Wagner said. “So, it’s always best not to startle them.”

Lerczak said, “If you approach them, they will get startled and fly away, which would be a waste of energy. If you are watching eagles from the car, do not get out of the car, and do not make any sudden noises, such as slamming the car door.”

Lerczak said that eagles should be observed at a distance. 

“You definitely want to have binoculars with you,” Lerczak said.

Wagner echoed Lerczak’s advice. “I would never want to be around them during nesting. I already had a goose hit me upside the head as I approached its nest. Can you imagine what that would be like with a raptor?”

It is also not a good idea to feed eagles. “Avoid feeding them because it could hinder their independence in the wild,” Wagner said. 

“You don’t ever want to introduce new things to a wild animal’s diet,” Lerczak said, “I’ve heard of people trying to feed eagles bread, or meat or animal carcasses. This actually verges on wildlife harassment.” 

Lerczak maintains that eagles can hunt and supply plenty of food by themselves and that they would not be attracted by bread.

“Eagles are predatory birds, eating geese and ducks, whatever they can find, including carcasses,” Lerczak said. “One time, I saw an eagle chasing a goose. Geese are fast flyers, but this eagle managed to catch up with the goose and knock it down from the sky.”

Chicks will hatch in February and March, and leave their nests around May and June. The eagles that do not return north come springtime are considered resident birds. Illinois, said Lerczak, now boasts the second-highest winter eagle population in the country, behind only Alaska.

Although eagles are trying to conserve their energy through the winter, Lerczak said there is “fantastic action” to be seen simply by waiting and watching.

“Eagles are solitary, territorial birds, and don’t usually travel in flocks,” Lerczak said. “They will travel in pairs when they are breeding. Right now, you will undoubtedly see some breeding behavior. Eagles display courtship by chasing each other, grasping talons, and then dropping from the sky like stones. Be patient and enjoy what you can simply by watching.”