If you sense there haven't been as many bald eagles around the Quad-Cities this winter as in some years, you're right.
Kelly McKay, the Hampton-based wildlife biologist who conducts the Mid-Winter Bald Eagle Survey for the Quad-Cities area, said he counted a total of 1,258 birds along his 81½-mile route in January compared to 2,199 in 2018. That's down 941.
The reason is weather. December was relatively mild in the northern United States, meaning rivers stayed clear of ice and food was available, giving the birds no reason to fly south in search of open water, McKay explained.
By the time temperatures turned cold over the past three weeks, the season was well underway and McKay said he suspects the eagles will just "tough it out where they are" rather than flying south. That's because they would just have to turn around in a few weeks to fly north when nesting season begins at the end of February and early March, he said.
"If we don't get significant ice cover in December or early January, you just never get the big eagle numbers," he said. "All in all, it's been a pretty lackluster year."
McKay counts eagles along the Mississippi River from Clinton to New Boston, Ill., as well as a one-mile stretch at the confluence of the Mississippi and Rock rivers. The counts are part of a national survey administered by the U.S. Army Corps of Engineers. The goal is to collect, analyze and maintain long-term population data on the once-endangered eagle.
McKay conducted this year's count on Jan. 10, 11 and 15 when temperatures ranged from 17 to 32 degrees. "It had just started to get cold," he said. "The ice cover over the entire stretch was only about 9 percent. It was a lot different than it is now."
Of the birds counted, 851, or 67.6 percent, were adults, and 395, or 31.4 percent, were immature birds. That ratio speaks well for the overall health of the population, he said.
Two other observations:
• Lock and Dam 14 near LeClaire and Lock and Dam 15 in Davenport have been "destroyed" as areas where eagles flock in large numbers, McKay said.
While that may surprise eagle enthusiasts who frequent both sites and see anywhere from 20 to 30 birds, this number is down substantially from what McKay said he saw in the 1980s when he began doing eagle counts with Elton Fawks. Fawks (1908-1989) was an East Moline citizen-scientist whose data helped make the connection between use of the pesticide DDT and declining eagle populations in the 1960s.
The change at 15 may be temporary due to activity surrounding the rebuilding of the downstream lock wall, McKay said.
But the site at 14 "is an example of loving the resource to death," he said.
"It's the photographers. There are days when 100 people walk right up to the trees. I personally wish the Corps wouldn't allow it, but that's not going to happen."
To accommodate visitors, the parking lot at the lock and dam has been expanded "right into the trees," McKay said. "That's their (the eagles') major foraging habitat."
On the Illinois side, new housing has removed or disturbed foraging habitat.
• A decrease in the amount of dead gizzard shad, a type of fish, visible along the river that traditionally accounted for a large part of an eagle's diet. McKay has been concerned about this for several years.
The fish die because of a lack of oxygen caused by the water icing over; it's a normal biological process and nothing to be alarmed about he said. But if something is happening to the gizzard shad, that could have implications for eagles, McKay said.
McKay believes a lack of shad is one of the reasons eagles are flying further inland, to eat gut piles (from deer), road kill or dead livestock. "People see more birds inland and they think it's a good sign. To me, that's not a good sign."
Fisheries specialists with the Iowa Department of Natural Resources have vigorously disagreed with McKay's assessment, saying their annual samplings show that the gizzard shad population as flat, neither increasing nor decreasing.
But, McKay said, "if I'm right and there is a shortage of fish and that source of inland food isn't available (because of deep snow cover) then they (the eagles) are in a really tough spot."