Eagle Roost Count February 14, 2010 Lower Wisconsin River

Hello all of you fine eagle enthusiasts:We collectively counted 16 less eagles yesterday than we did two weeks ago. Twenty-eight eagles (65%) also concentrated in off-river roosts rather than in roosts along the river. Kay Roherty reported two separate carcasses near Leland Roost that 12 of the 17 eagles that used Leland Roost in the evening were feeding on during the day. The uniform and relatively deep snow cover may be limiting food availability in these off river roosts even though the number of eagles using off-river roosts has remained relatively constant since December. Also of interest, an immature (4-year-old) eagle with an unusual amount of white on it’s back was seen using the Leland roost. This bird has also been seen on Eagle Island in Prairie du Sac on Eagle Days (mid-January) and last week. The lack of eagles using upriver roosts suggests a shift of eagles from upriver roosts in mid-January to off-river roosts now.

Up until Sunday the river was open from the dam down to Ferry Bluff and then again near the Highway 23 bridge. On Sunday, Jeff Jahn reported the river ice across from Arena suddenly breaking up during the day. Thus, eagle use of the river was still predominantly down-river and not upriver. If food is relatively equally distributed along the river from the dam to Lone Rock then this suggests that eagles, when given an alternative, will not remain up-river. Alternatively, there is more food in the down-stream reaches as compared to the dam. Why this would be so I cannot guess. Three to four eagles were seen near Blackhawk canoe rental during the day on Saturday. This area is near Ferry Bluff Roost but the Cody’s did not see any eagles flying into Ferry Bluff Roost on Sunday.

Of course, with the lower number of eagles during this count it is also likely that birds have shifted much further downstream to Eagle Valley on the Mississippi River or further down the Mississippi River in Iowa or Illinois. When we had telemetered eagles in the area (2000-2003) several birds made similar shifts during cold periods of the winter.

On Saturday I also saw an adult golden eagle near the McDonald (and Fox) roost in the afternoon. An adult golden eagle was also reported near the Fox Roost in mid-January (along Cassell Road) so this might be the same bird. Perhaps it is using the Fox Roost and is one of the age unknown birds seen using that roost yesterday. The bird could also be using the Ederer/Been Roost.

As always, thanks much for your efforts.

Jeb

Count Results:

Adult Imm. Unkn. Total

Blackhawk 0

Sugarloaf 1 1

Ferry Bluff 0

Fox 1 5 6

McDonald 0

Jones Slough 2 2

Lone Rock 4 2 6

Big Hollow 3 3 6

Ederer/Been 3 1 1 5

Leland 12 5 17

TOTAL 24 11 8 43

Volunteer Hours: 40