on the Rise

Eagles and pelicans no longer a rare sight

by John Mielke

There are hundreds of bird species in Door County, and Rob Hults, executive director of the Open Door Bird Sanctuary near Jacksonport, credits a welcoming habitat with making that possible: The county has thousands of acres of preserved land, much of it with mature trees and an ample food supply.

Door County is a perfect home for the merlin falcon, pileated woodpecker, screech owl and many others, but two of the largest and most talked-about birds may be the bald eagle and the American white pelican. Not long ago, seeing a bald eagle or white pelican in Door

County was rare, but today, you don’t have to drive very far or look very hard to spot either one.

What happened? Why are they back?

The Pelicans’ Story

“Pelicans started showing up in Wisconsin in the early ’90s, specifically in lower Green Bay,” said Joshua Martinez, district ecologist for the Wisconsin Department of Natural Resources. “That was the first epicenter. The reason why they came here is still fuzzy.”

Most avian experts believe, however, that drought in North Dakota and South Dakota is responsible. Martinez said that drought caused a massive number of failed nest attempts in those two states, so pelicans may have had no choice but to expand their migration route – and they discovered Green Bay.

“They show up here and realize that nesting is capable for them,” Martinez said. “They saw that the food resource was extremely abundant, with all the small bait fish among all the other fish that we have here in the bay, and since then, they have continued to grow in population.”

Tom Erdman, a former curator at UWGreen Bay’s Richter Museum, noted that during the late 1970s, a single white pelican made news when it spent the summer off Chambers Island.

“In 1981, we had a flock of 24-25 pelicans roam around the state, stopping at Mead Wildlife Area [north of Stevens Point], Green Bay and down to the Horicon Refuge,” Erdman said.

On lower Green Bay, a flock hung around a double-crested cormorant colony for five or six years before its members finally tried to nest. The first nesting attempt in 1994 by two pairs of pelicans failed, possibly because researchers kept birds off the nests too long.

“In 1995, we had nine nests, and those produced the first young,” Erdman said. “This happened because our growing colony of cormorants had finally begun to switch from tree and platform nesting to ground nesting. Once the cormorants did this, the pelicans joined them.”

Pelicans prefer islands because they offer protection from predators, and pelicans don’t seem to mind co-nesting with cormorants. Maybe that’s because pelicans and cormorants not only nest together, but they also feed together. White pelicans feed on the surface, and cormorants dive.

“They’ll actually work together as a group,” Martinez said. “It’s kind of hilarious to watch.”

Will the pelican population continue to grow? Martinez said that while there is plenty of food, the availability of nesting space will be key. But he doesn’t see that becoming an issue anytime soon.

For those who enjoy watching the white birds with a nine-foot wingspan floating on the air currents above Door County, there should be plenty of opportunity to enjoy that sight.

The Bald Eagles’ Comeback

If you like a good comeback story, you have to love what’s happening to the bald eagle in Wisconsin and Door County. Erdman said that eagles were originally scattered around the county, including on Detroit and Washington islands.

“When Spider Island was made part of the federal refuge system back in 1913, there was an eagle nest and a great blue heron rookery, too,” he said.

Three letters played a big role in changing all of that: D, D, T. The highly toxic pesticide was used in agriculture throughout the state and in Door County orchards after World War II, replacing lead arsenic, which had been applied since the 1890s. Because of the shallow Door County soils and the fractured dolomite surface, DDT quickly entered the aquatic system and was magnified throughout the food chain.

“It was stored in the birds’ fat reserves and affected the calcium metabolism needed to produce quality eggshells,” Erdman said.

To put it mildly, the bald-eagle population declined. Erdman helped former Wisconsin Department of Natural Resources (DNR) researcher