Why Do We Count Eagles?

Every two weeks-from early December to late February- Ferry Bluff Eagle Council (FBEC) volunteers count the eagles that use 6-8 traditional night roosts in the Lower Wisconsin River area. Volunteers go where they can get a good view of the eagles entering the steep protected valleys to spend the night. The totals help give FBEC an estimate how many Bald Eagles are in the area, as well as examine the number of adults and immatures present on a given date.

The counts are invaluable information used by FBEC to document the number and location of eagles in the area. Having conducted the roost counts since 1988, FBEC has established the best database on eagles in the area – a useful tool in working with governments, landowners, and others interested in eagle conservation.

Variability in when eagles concentrate in the Sauk Prairie area is likely due to the interaction between eagle behavior and the vicissitudes of winter weather and winter’s effect on food availability.  Looking for these patterns in the data across all of these years is a valuable role for FBEC and is critical for our understanding of winter eagle behavior.  When laws are made to protect eagle habitat, for example, the range of dates is important to consider.  Collectively eagles have concentrated in the Sauk Prairie roosts (Sugar Loaf and Blackhawk) any time from early December to late February.  In any one year, however, eagles have concentrated their use of these two, up-river roosts for only 3-6 weeks of this period.  Eagle use of down-river roosts often occur when up-river roosts are vacant or eagles leave the Lower Wisconsin River entirely. Dates that prevent disturbance need to reflect long-term use and not any one year.

The roost count data that FBEC collects thus provides a marvelous tool that we can use to not only try to understand eagles better but to guide the many activities that our community engages in each year.  Information that our many volunteers have worked so hard to collect is being used frequently to address a myriad of questions such as the timing of eagle releases, evaluating the significance of disease outbreaks to whole populations, public understanding (i.e. Where have our eagles gone?), appropriate timeframes for construction along the river, and a host of other issues.  We are always amazed at how many ways these data can be utilized, and it is gratifying that FBEC can make this information available each year.  While the Sauk Prairie community and surrounding areas continue to grow and develop, these data will become even more valuable as we attempt to merge the interests of eagles and people in a sustainable manner.

Current Roost Count Summaries

Bald Eagles In Sauk-Prairie & Spring Green Area

The link below goes to our e-newsletter Roost Count Summary page. You will find table and graphs that we track Bald Eagle population in the Sauk-Prairie and Spring Green area currently, based on bi-weekly roost counts conducted by Ferry Bluff Eagle Council (FBEC) volunteers. Up-river roosts include Black Hawk and Sugar Loaf. Down-river roosts include Ferry Bluff, Fox, McDonald, Lone Rock and Ederer/Been.

December 21, 2021 Roost Count

See the count report here.

Bald Eagle
Bald Eagle