36th annual New Hampshire Mid-winter Bald Eagle Survey Update by Chris Martin

Posted on February 1, 2016
An eagle transitioning from immature to adult plumage seen near historic Roby's Store in Hooksett. David Lipsy photo.

An eagle transitioning from immature to adult plumage seen near historic Roby’s Store in Hooksett. David Lipsy photo.

We have just wrapped up the 36th annual New Hampshire Mid-winter Bald Eagle Survey, part of the national Mid-winter Bald Eagle Survey coordinated by the U.S. Geological Survey. The 2016 count results are comparable to our outstanding count numbers in 2015, which is fantastic considering how much open water there was all across the state, and how little the weather conditions forced eagles to concentrate in their typical wintering areas.

In contrast to last year’s bone-chilling weather, most of the state had very mild conditions on this year’s Count Day (Sat. Jan. 9 statewide, except Thurs. Jan. 7 in Lakes Region). A total of 94 volunteer observers participated in the 2016 Count Day, and located 89 individual eagles on Count Day alone, just one less eagle than 2015’s record high of 90 seen. Top regional honors for most eagles seen on Count Day 2016 go to the Lakes Region where 22 eagles were tallied on Count Day. The Connecticut River watershed was right behind with 21 birds, and the Merrimack River watershed was third with 18 seen.

Statewide Count Day Results: This year we located 89 Bald Eagles (58 adults, 30 immatures*, 1 unknown age) in New Hampshire on Count Day, just one bird less than the 90 seen on Count Day 2015. See the PDF graph showing Count Day results since 1981.

Statewide Count Period Results: The official “Count Day” occurs within a more inclusive two-week “Count Period,” which spanned the interval from January 1-15, 2016. We keep track of eagles seen during this 15-day interval. Any additional individual birds that are reported during the Count Period, and which are distinguishably different (by plumage or location) from Count Day birds, are added to calculate an overall Count Period total.

During this year’s Count Period, we documented a total of 115 Bald Eagles (79 adults, 35 immatures, 1 unknown age). As for overall long-term trends, the number of eagles counted during the Mid-winter Survey in New Hampshire continues to double roughly every 10 years; for the Count Period in 2015 we had 110 eagles, in 2005 we tallied 55 eagles, in 1994 we counted just 25, in 1984 we counted only 12.

So, where were all these eagles found during the 2016 Mid-winter Survey? We located the following numbers of eagles in the state’s five major eagle wintering areas (and a few elsewhere across the state) during the Count Day and the Count Period:

Adult pair of bald eagles seen near Reflection Pond on Androscoggin River during the Count Period. Ravenel Bennett photo.

Adult pair of bald eagles seen near Reflection Pond on Androscoggin River during the Count Period. Ravenel Bennett photo.

Androscoggin River – Total of 9 Bald Eagles seen, including 8 individuals (5 adults, 3 immatures) seen on Count Day (6 observers), with 1 additional eagle (1 adult) confirmed during the two-week Count Period. Ravenel Bennett found an adult pair on the Androscoggin River in Shelburne NH during the Count Period.

An immature eagle found on the Connecticut River near the Windsor-Cornish covered bridge. Judy Lombardi photo.

An immature eagle found on the Connecticut River near the Windsor-Cornish covered bridge. Judy Lombardi photo.

Connecticut River** – Pace-setting total of 34 Bald Eagles seen, including 21 individuals (14 adults, 7 immatures) seen on Count Day (14 observers counting for NH’s total), plus 13 additional eagles (10 adults, 3 immatures) confirmed during the two-week Count Period. Judy Lombardi saw an immature near the Cornish NH/Windsor VT covered bridge on Count Day.

Great Bay/Coastal – Total of 18 Bald Eagles seen, including 16 individuals (8 adults, 8 immatures) seen on Count Day (15 observers), plus 2 additional eagles (2 adults) confirmed during the two-week Count Period. Cheryl Mrozienski got up early to see an adult pair at their snowy Bow Lake nest at first light.

Lakes Region – Total of 23 Bald Eagles seen, including 22 individuals (18 adults, 4 immatures) seen on Count Day (19 observers), plus 1 additional eagle (1 immature) confirmed during the two-week Count Period. Exceptionally mild conditions w/o wind, open water everywhere, Libby Corbin saw an eagle while she was kayaking on Winnipesaukee!

These eagles were NOT counted in the 2016 Mid-winter Bald Eagle Survey! Susan Wrisley photo.

These eagles were NOT counted in the 2016 Mid-winter Bald Eagle Survey! Susan Wrisley photo.

Merrimack River – Total of 24 Bald Eagles seen, including 18 individuals (10 adults, 7 immatures, 1 unknown age) seen on Count Day (35 observers), plus 6 additional eagle (5 adults, 1 immature) confirmed during the two-week Count Period. David Lipsy and several other observers found this lovely sub-adult (counted as immature by protocol) in Hooksett. Susan Wrisley managed to photograph David Lipsy immersed in his pursuit of eagles.

Saco River/Ossipee River, and from elsewhere across NH – Total of 7 Bald Eagles seen, including 4 individuals (3 adults, 1 immature) seen on Count Day (5 observers), plus 3 additional eagles (3 adults) confirmed during the two-week Count Period.

A FEW NOTES ON TERMINOLOGY:

* Following the standardized rules of the National Mid-winter Bald Eagle Survey, all sub-adult plumage eagles (including those displaying almost full adult plumage but with minor remnants of immature plumage – often called “dirty adults”) are counted as “immatures” rather than as “adults”.

[** To avoid double-counting, VT and NH “partition” the Connecticut River, with VT credited with all eagles seen upstream from Wilder Dam, and NH credited for all eagles seen downstream from the dam, regardless of which state’s volunteers see the birds, or which state the bird was flying over or perched in.]

This was the 36th consecutive year that New Hampshire Audubon has coordinated New Hampshire’s part of the National Mid-winter Bald Eagle Survey, starting with the Winter of 1980-81. More information about the national survey, including a 25-yr (1986-2010) trend analysis recently published in Journal of Raptor Research (attached PDF), can be found HERE.

With completion of the 2016 Mid-winter Survey, NH eagle-watchers can turn our attention towards the upcoming eagle breeding season. Just 5-8 weeks from now, most of our breeding pairs will be laying eggs and beginning their 5-week incubation period. Please watch for, and report, any courtship or nesting activity that you may observe as NH Audubon continues to monitor and manage NH’s breeding eagles in collaboration with NH Fish & Game.

NH Audubon monitors Bald Eagle abundance and distribution throughout New Hampshire each year as part of an annual contract with the NH Fish and Game Department’s Nongame and Endangered Wildlife Program. We have also received outstanding financial support from TransCanada Corporation. Donations to NH Audubon’s Conservation Department in support of this work are always appreciated. And thanks once again to each and every one of you who donated your time and skills to participate in this year’s successful Mid-winter Bald Eagle Survey!