The question of whether the bald eagle population is dwindling in the Midwest continues to confound bird watchers along the Mississippi River.

The organizer behind an annual winter count conducted in January by hundreds of volunteers revealed fewer young eagles along the Mississippi River and its tributaries.

But the U.S. Fish and Wildlife Service maintains that the bald eagle recovery is progressing at an “impressive” rate.

Kelly McKay, a wildlife biologist based in northern Illinois, says his observation is that, if there are fewer eagles along the waterways, it’s because they are moving inland to find food. He thinks it’s because there are fewer gizzard shad in the water.

“If there’s something going on that’s a problem with shad, that’s eventually going to impact bald eagles,” McKay said. “You can’t eliminate 90 percent of a species food source and not start to see the impact to the population.”

If eagles can find enough food just a few miles inland, what’s the big deal?

“You get the one-two punch of increased collisions with cars because they are feeding on roadkill,” McKay said, “and you’ve got the problem of them picking up lead from hunter-killed deer.”

He says they also may feast on dead livestock, which could have unknown consequences. He admits his theory isn’t universally accepted — and says more research is needed to determine whether the eagle population is truly at risk.

The U.S. Fish and Wildlife Service says it is working with states on nesting surveys to produce an updated population estimate later this year.