"I come down here almost every day because I know the eagles will be coming in," Allison told the Journal & Courier.
More than 20 eagles, bald and golden, were on the West Lafayette side of the river Friday morning behind Williamsburg on the Wabash apartments.
An avid birder, Allison has enjoyed taking photos of them since he got his first Kodak camera at the age of 11. Now retired from a 40-year career in the grounds department at Purdue University, he can spend more time studying his favorite animal.
"Oh, they're beautiful," said Terry Griffith, an employee at the apartment complex. "Especially when you get to watch them fish."
Most of the eagles seen Friday migrated from Canada in November in search of open water to fish. They'll likely fly back north in March. However, there's no shortage of eagles in Indiana, said John "Barny" Dunning, professor of wildlife ecology at Purdue.
The state has 150 to 175 territorial pairs, he said.
Fifty years ago such a sight would've been surprising.
But after 30 years on the endangered species list, the species now is considered fully recovered, Dunning said.
The birds of prey still are protected under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act.
Bald eagles are primarily fish eaters. After World War II, DDT was made available as an agricultural insecticide; run-off would end up in rivers and lakes and kill fish.
The insecticide was not fatal to adult bald eagles, but it had a devastating impact on reproduction.
"They would lay eggs with no shell," Dunning said. The female would sit on her clutch of two or three eggs and crush them with her body weight.
So the U.S. Environmental Protection Agency banned DDT in 1972, which allowed the bald eagle to recover.
The comeback pleases Allison.
"I like to see them in their natural habitat instead of sitting in a zoo somewhere," he said.