Iowa Natural Heritage Foundation: Bald Eagles Soaring Back to Iowa

It was a cold December morning, and several bald eagles (Haliaeetus leucocephalus) were hunting for breakfast along the Des Moines River, just downstream from the Gladys Black Refuge. A dead cottonwood leaned precariously over the water, marking time before its inevitable plunge to the river below. Several eagles of varying ages and coloration were perched among the branches of this gnarled monarch.

All were scanning the river below. There, winter’s icy grip had plunged the water temperature to an intolerable level for many gizzard shad (Dorosoma cepedianum), the eagle’s favorite prey. These fragile fish were dying in great numbers.

Suddenly an adult eagle launched … gliding out and over the river. Then with a quick pirouette and a well-executed dive, he snatched a fish from the river below. Returning to the lookout tree and clutching a small shad, he had barely landed when a juvenile eagle landed beside him. Immediately, the juvenile began pummeling the adult with his wings. And, although the adult used his own wings to block the blows somewhat, he eventually dropped the shad and flew away. Quickly, the juvenile spiraled down to the river and snatched the fish.

Why did an experienced adult allow itself to be robbed, without putting up much of a fight? Surprisingly, I witnessed the robbery of several more adults by juveniles that winter.

Later, Pat Shlarbaum, an Iowa DNR biologist, told me that adult eagles seem to sense these thieves with brown coloration are juveniles. And their paternal instinct causes them to give up the shad. As adults, they can usually catch another fish with little difficulty, while a young eagle might still be on his learning curve.

This was just one of the many fascinating behaviors I have witnessed during 14 years of bald eagle photography. During this lengthy initiative, most of my time has been spent along the Des Moines River, at various points between the Red Rock spillway and Mahaska County road T-29.

A favorite haunt has been a property adjacent to the Gladys Black Refuge, an INHF project site. Like Gladys, I’ve been thrilled to view and photograph eagles in this area. The refuge is truly a special place for bald eagles — and INHF and many others have ensured it will stay that way.

Bald Eagles soaring back to Iowa