Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

Two eagles in flight © Don Blegen

The cold winter months of December through February are good times to find and watch bald eagles in Wisconsin.
© Don Blegen

December 2012

Eagle tag

Musing about promiscuous play, or is something more?

Don Blegen

On windy days in late fall, I watch eagles play aerial "tag" above my house. Sometimes a dozen or more eagles soar and maneuver, diving upon one another, performing breathtaking acrobatic maneuvers of evasion and pursuit.

Walt Whitman, the great 19th century American poet, apparently witnessed this long ago:

Eagles flying © Don Blegen
Wisconsin offers many opportunities to view eagles.
© Don Blegen

Skirting the river road, (my forenoon walk, my rest,)
Skyward in air a sudden muffled sound, the dalliance of eagles,
The rushing amorous contact high in space together,
The clinching interlocking claws, a living,fierce, gyrating wheel,
Four beating wings, two beaks, a swirling mass tight grappling,
In tumbling turning clustering loops, straight downward falling,
Til o're the river pois'd, the twain yet one, a moment's lull,
A motionless still balance in the air, then parting, talons loosing,
Til o're the river pois'd, the twain yet one, a moment's lull,
Upward again on slow-firm pinions slanting,their separate
diverse flight,
She hers, he his, pursuing.

- Walt Whitman, The Dalliance of Eagles

Coincidentally, I live along what locals call "The River Road" between Spring Valley and Elmwood, next to the Eau Galle River, a migratory path in western Wisconsin, a path that all sorts of migrating birds use in both spring and fall. Many of these birds, like ducks, geese, swans, cranes, warblers, etc., just move on through. But for some reason, the eagles do not. They accumulate for a while here in the autumn.

There may be several eagles roosting every night in the tall white pines on the bluffs behind my house, gradually accumulating to several dozen. On days when the wind is strong out of the northwest, they come out to play tag. The immature birds outnumber the adults by about four-to-one, indicating very good reproductive success among Midwestern bald eagles. It doesn't seem to matter, though, whether they are adults or younger birds when it comes to playing tag. Sometimes it will be an adult playing with an immature. Sometimes vice versa. Sometimes immature on immature or adult on adult.

They fly into the autumn wind until the wind slows or stops them, the eagles hovering motionless until they stall, then wheeling and coursing downwind, losing altitude and picking up speed, until they have enough velocity to rise again into the wind. Quite often one eagle will maneuver into a position where it can dive upon another just as it turns to face the wind.

I have tried to research some reason for this behavior, without much real success. Some sources say it is a courtship thing. Walt Whitman certainly seemed to think so. But there are a couple of things wrong with that idea. Eagles mate for life, so why this promiscuous play? Whitman's "dalliance" would certainly violate that lifelong bond. Both mature and immature eagles play this game with each other. Also, eagles mate in spring, so why this aerial play in the fall?

As one eagle dives upon another, sometimes they will just fly in tandem, barely brushing each other. But sometimes it is more like an attack. The one being attacked will do a half-roll to an upside down position, talons extended to meet the talons of the diving bird. Once in a while they will grasp talons and go into a falling spin, around and around, dropping perhaps a hundred feet before breaking apart.

This is Whitman's "living, fierce, gyrating wheel." Some claim they have seen eagles in a spin fall to the ground and die. I have never seen that happen. But I have seen them break apart only 50 feet or so above the ground. In the recent birding movie The Big Year, there is a great sequence of this spinning behavior. It is spectacular.

There seems to be a common belief that eagles mate in midflight, and that this tag and spinning behavior is a prelude to midflight copulation. I doubt that very much. Eagles mate like chickens or any other bird, usually right on the nest. And in the spring, not in the fall.

So what's going on here? It may be that eagle tag is practice for later serious courtship. It may be that it is a dominance thing, establishing some kind of eagle pecking order. Or it may have a much simpler explanation.

If I were an eagle, I would like to demonstrate my flight skills. If I were young, I would like to show off a bit, show those old timers (and those lovely young lady eagles) my aerial mastery. If I were an old veteran, I would like to show those young whippersnappers a thing or two and put them in their place.

I have seen an eagle deliberately swoop over another eagle perched in a tree and do a full barrel roll above the sitting bird. A challenge? Or an invitation to come out and play? I think they might be doing it simply because they enjoy it, because it's fun. It sure looks like fun to me!

BALD EAGLES

Bald eagles have enjoyed a remarkable recovery in Wisconsin and nationwide since being placed on the state and federal endangered species lists in the 1970s. Eagles were removed from Wisconsin's endangered list in 1997 and from the federal list in 2007. See why bald eagles winter in southern Wisconsin and learn about one popular event built around these birds. Bald Eagle Watching Days in Sauk Prairie is held in January. See the video on DNR's YouTube channel at:

Watch us on YouTubeWatch a video of Bald Eagle Watching Days  

Don Blegen Photographer, author and retired biology teacher writes from Spring Valley.