March 9, 2021: Territorial Battle At Great Spirit Bluff

On March 9 at about 6:37am central time, GSB watchers witnessed a peregrine falcon territorial battle. Resident female Nova came back after a three-day absence and drove interloper Nina away. After ousting Nina, Nova copulated with Newman and disappeared again.

Are the falcons okay?

Neither falcon appeared to have been seriously injured in the fight. We zoomed in on Nova’s eyes – our primary concern – and they appeared to be fine. Either Nina or Nova could come back to Great Spirit Bluff, try to claim a different nest (the La Crosse US Bank nest box is the closest, at five miles away), or skip breeding entirely. Right now, raptor migration is in full swing. But all the activity should ebb within the next two weeks as everyone settles down. We believe that the falcons will eventually lay eggs, although the turmoil could push GSB’s schedule back. 

Why didn’t Newman defend either falcon? Is this unusual?

Female falcons [falcons] are about a third bigger than males [tiercels]. It would be very risky for a male to take on a larger female, especially at close quarters, so males usually fight males and females usually fight females.

It is not unusual for falcons to fight over territory, especially in the spring. But it is a little unusual for Nova to disappear. Usually a female peregrine shows up a little after the male, accepts her mate’s courtship, and chases other female falcons away almost as soon as they appear. But Nova disappeared between March 6th and March 9th, came back to fight Nina over the territory, and vanished again after copulating with Newman. Perhaps she is considering another nesting site or distracted by all of the activity around her. We’ll see what happens over the next few weeks. 

To learn more about falcons in general and GSB in particular, follow this link: To learn more about our work with peregrine falcons, check out our banding reports and papers: