Montana Best Times: Big Sky Birding Column

The Ubiquitous Bald Eagle: It Is Coming Nearly Full Circle Since the Days of Lewis and Clark (March 2005)

In the January issue of Montana Best Times, the discussion centered on the difference between a Carrier Pigeon, Homing Pigeon, Messenger Pigeon, and Passenger Pigeon. In this month's column we will learn about the ubiquitous Bald Eagle and the nearly full circle the population has experienced since the days of Lewis and Clark.

The year 2005 marks the 200th anniversary of the famed entry of the explorers Meriwether Lewis and William Clark on April 25, 1805, in what is currently called the state of Montana. Wouldn't it be interesting to know how Bald Eagles (Haliaeetus leucocephalus) are doing today compared to the days of Lewis and Clark?

The eagles and the island
Native Americans are without question the first ones to document the existence of Bald Eagles in Montana. However, they left no written record - only stories and customs passed down through generations.

The winter before Lewis and Clark ever entered Montana, the expedition was holed up in Fort Mandan in current-day North Dakota. It was at Fort Mandan they learned about the lay of the mysterious land they were about to explore the next summer. And the Hidatsas at Fort Mandan mentioned that a good indication they were entering the area of the "Great Falls" was the presence of an eagle's nest on the island below the falls.

The first written documentation of Bald Eagles in Montana by white explorers occurred on April 27, 1805, when Lewis and Clark entered the area at the confluence of the Yellowstone and Missouri rivers. Lewis wrote, "The Bald Eagle is more abundant here than I ever observed."

On May 7, 1805, as they traveled west up the Missouri River, a similar notation: "We continue to see great numbers of Bald Eagles."

The Corps of Discovery struck it rich on June 14, 1805, when they wrote what they noticed below a waterfall: "In this Island on a Cottonwood tree an Eagle has placed her nest; a more inaccessible spot I believe she could not have found; for neither man nor beast dare pass these gulphs which separate her little domain from the shores."

The falls, one of the five falls that comprised the original Great Falls, was named shortly thereafter "Black Eagle Falls." The island they were referring to is still there today and is known locally as Black Eagle Island, most likely in reference to older bald eaglets that are black in color when they are still in the nest.

There are two other Lewis and Clark accounts of Bald Eagles in Montana: Aug. 10, 1805 - "I saw several Bald Eagles" when writing about the upper Jefferson River; and on Aug. 3, 1806 Lewis on the Missouri River noted, "a number of Bald Eagles."

But the most significant notation about Bald Eagles for the Lewis and Clark Expedition all revolves around the discovery of the Bald Eagle nest below these falls near the current town of Black Eagle, a suburb of Great Falls, Mont. The last time the eagles nested on Black Eagle Island is difficult to determine, but to the best of my knowledge the nest was still standing in the 1860-1870s. Great Falls became a thriving metropolis in the 1880s, and the eagles and nest became a thing of the past.

But has it? Let's examine the history of the Bald Eagle by reviewing its status over the years and make predictions as to the future of Bald Eagles in Montana and North America, for that matter.

Decline and recovery
The Bald Eagle is endemic or native to North America. It's geographic range extends from Alaska to Newfoundland and from Baja Mexico to Florida. It can occupy a varying degree of habitat ranging from lake shores and coastlines to cyprus swamps and mangroves. It can feed on a variety of prey, but typically capitalizes on fish and waterfowl and occasionally carrion.

It was first described by Linnaeus in 1766 through a type specimen collected in South Carolina. In 1782 it was selected as our national symbol, because of its obvious large size, and talon and beak features, symbolizing power and strength. By the late 1800s and the early 1900s Bald Eagle numbers started to decline, mainly due to shooting and perceived competition with pioneers for food. The Migratory Treaty Act of 1918 mainly slowed down the onslaught of taxidermy and egg collections. In 1940, the Bald Eagle Protection Act was passed (in addition to a Golden Eagle amendment in 1962). Predator control measures and in some cases bounties were in place in some states until the mid-1950s.

After World War II, pesticides such as DDT came onto the scene around 1945, and aerial spraying for forest insects become popular. In 1962 Rachel Carson published "Silent Spring" which centered on the plight of birds through pesticide exposure. In 1967, the southern race of the Bald Eagle was classified as endangered, the northern race of the Bald Eagle threatened.

Egg-shell thinning was becoming commonplace in raptors (e.g. Bald Eagles, Peregrines) and some colonial nesting birds (e.g. Brown Pelicans), which created quite a stir nationwide. DDT finally got banned in 1972, and in 1973 the Endangered Species Act became law.

Lead poisoning and power line mortality became the issues for Bald Eagles in the 1980s. Once lead was banned from waterfowl hunting, coupled with a successful catch and release fishing program, Bald Eagle populations started to explode in most areas of North America. Except for habitat and subdivision problems in the Southwest and mercury contamination problems in the Great Lakes region, the Bald Eagle is well on the road to recovery in North America.

Numbers
So just how plentiful are Bald Eagles? In North America and on a continental scale, their population is estimated to be somewhere around 80,000 to 100,000 individuals. Most of these Bald Eagles are found in Alaska and Canada, however.

What about locally? In Yellowstone National Park, there were 14 nesting pairs in 1980, and there are 32 nesting pairs today. In the Greater Yellowstone area, there were 50 nesting pairs in 1980, and 146 nesting pairs in 2003.

In Montana, there were 37 nesting pairs in 1982, and well over 200 nesting pairs today. In fact, nesting Bald Eagles are so numerous in Montana, that it is becoming difficult to monitor all the new nest sites. So it is fair to say, Bald Eagles are doing remarkably well.

Waiting for return to Black Eagle Island
Will we ever know whether we have come the full circle in Montana, as far as Bald Eagles are concerned, compared to the days of Lewis and Clark? Probably not, because much of what they wrote about was qualitative and anecdotal in content. What we really needed to compare today to the past was quantitative and factual data. That simply doesn't exist from the distant past. But we do have a Lewis and Clark record of Bald Eagles nesting on an island downstream of Black Eagle Falls.

And if we want to judge whether we have come the full circle with the Bald Eagle since Lewis and Clark's time, then the final benchmark will be the day Bald Eagles return to nest on Black Eagle island near Great Falls. Regardless of whether that will ever occur in my lifetime, the simple fact that Bald Eagles have flourished in Montana like they have, is a success story in itself.

Now that the reader has a better understanding of the status of Bald Eagles in Montana, the next topic scheduled for the May issue of Montana Best Times will be ospreys.

Enjoy! And the Best of Big Sky Birding to you!