Eagles feast on deer
PHOTOS BY GARRY BRANDENBURG — Bald Eagles have great vision. And great vision allowed at least one eagle to spot a dead deer, killed by a vehicle strike most likely, not too far from the road shoulder off highway 330 northeast of Albion. The date of these images was Jan. 7, 2024, just prior to the onset of our first big snow storm of the winter. Once the deer carcass was located, many other eagles were quick to spot the buffet line of opportunity. When this author observed the 'crowd,’ with most just waiting for their turn, there were at least 12 eagles, both immature and mature, sitting in the bean field. My long lens was put to good work recording images of a predator/prey interaction. The transfer of nutrients and energy that once supported the life of the deer is now supporting the life of many eagles. It is nature in action.
Bald eagles are regal birds, very big birds and as birds of prey, offer opportunities to observe how they go about their struggles in life to survive. They eat fish primarily if they are using open water habitat below river dams.
Lake Red Rock is just one such place to view eagles all winter long. A fish called shad will commonly go through the gate system of Red Rock dam, become stunned by the turbulent water, and as these fish float downstream, eagles make easy pick ups of fish to eat.
Eagles have a wingspan of 6 to 7.5 feet. Males and female adults look alike with their typical white head feathers and white tail feathers. The body feathers are dark brown to black. If sitting, an eagle will appear to be about 3 feet tall. Body weight will range from eight to 15 pounds.
Female bald eagles are physically larger than males. Primary foods are fish, but waterfowl is fair game and injured waterfowl will be quickly spotted by sharp eagle eyes. Carrion is also on the menu.
Winter survival is a balancing act of finding foods and expending as little energy as possible to do so. So the ethical thing to do at or near an eagle nest is to not approach the nest which may cause the adults to fly away. Using a ground blind to observe eagles is one way to keep disturbance low.
Vehicles are great ground blinds so stay inside and let your binoculars do the work. All winter and next spring, do tune into the Decorah Eagle Nest Camera to observe from the distance and comfort of your warm home and laptop or desktop computer.
Elsewhere in Iowa, which is everywhere, bald eagles continue to scope out the landscape for any and all types of foods, and while the eagles are doing their thing, a dedicated group of eagle volunteers will be tabulating eagle numbers. These volunteers drive standard routes and
note all eagles they see along the way.
Nest monitoring is more specific. In Iowa, there are between 250 and 350 nests. Here, the objective is to document eagle pair activity at each nest, the result usually being the successful hatch of at least one, maybe two, sometimes three and rarely but still possible, four eaglets. A successful nest raised four eaglets at Lake Red Rock in 2023.
During 2023, eagle surveys over 1,663.5 miles of waterways were conducted during January. The count found over 2,900 eagles! That makes an average of almost two eagles per river mile. Our Mississippi River rated very high in this survey. The lower reaches of the Iowa River rated
higher eagle densities, and an important element of the survey teams was to keep track of immature numbers in contrast to adult eagles.
The proportion of immature eagles has since 1991, been very close to 30 percent. In January 2023, the rate was 32 percent.
Immature eagles have a lot to learn if they are to survive. Luckily, their brain is hard-wired to accomplish those tasks of finding food. Immature eagles retain the brown feathers of their head and tail until about the fourth year of life.
Several molts of these feathers occur to eventually allow the full white head and tail to become conspicuous. The white head may have a bit of a lead on development, and the tail is the last to become white to stay white.
Nest monitoring in 2023 of 329 eagle nests was checked on from late winter into early spring and summer. Successful nests numbered 66 percent. Twelve nests failed, and the remaining nest sites had an unknown outcome.
The average number of fledglings was 1.77 per nest — a very high rate, a good thing. So when all of the data for 2023 was summarized for all active eagle nest site territories and the young birds produced, a total of about 720 new eaglets took the airways over Iowa. There is a good chance that in 2024, a repeat successful year will take place.
Eagles have lots of things to accomplish. Most they can control. Some they cannot.
Eagles are vulnerable to a disease called Highly Pathogenic Avian Influenza, and they sometimes become electrocuted by high voltage power lines. A few may get struck by vehicles if the feeding eagle is so intensely concentrating on eating a dead raccoon, rabbit, or deer.
Their life is tough, but this bird is resilient. Overall, the Bald Eagles of Iowa are doing well.
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Winter wildlife sightings are fun. Sometimes, they are just a happenstance of you being at the right place at the right time. If so, enjoy the gift of free nature viewing.
If you are the adventurous type and want to make things happen, a hike into any one of the county parks this winter may reward you with critters large and small. Big critters are deer, an obvious big game animal, and then there are the much smaller animals of the prairie, forest of wetland.
Good observational skills and good use of binoculars will help you find all kinds of living species going about their daily life. They are engaged in life’s struggle to find food, shelter and other protective cover. Winter cover is their home and it must work to allow them to live another day. Storms with snow, ice or rain complicate things for them. Avoiding predators from the air or on the ground is a must. To say that all wildlife must remain diligent and aware of what is going on is an understatement.
Overall, they cope. Habitat development to enhance wildlife survival potential is something to plan during the winter for implementation next spring and summer. It will pay off in the long run.
My meager winter wildlife forays have allowed me to see several flocks of wild turkeys feeding in open fields. Of particular note, the turkeys were (I think) of a weather change prior to the snow storm, so they were finding all they could to eat before snow covered the ground too deep.
I have seen a large flock of mallard ducks on the Iowa River, in a bend of the watercourse, in a spot isolated from most human disturbances. It was good to see at least 28 mallards in that group.
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Deer antler measurement requests are trickling into this author. I am an official measurer for archery taken big game for the Pope and Young Club, and I am also certified to conduct scoring for the Boone and Crockett Club, who like and want the data from all species of North American big game regardless of weapon type used to take the animal.
Some very nice white-tail deer antler sets have been presented for the tape. I have the owner assist in the process as base lines are determined and marked, as any non-typical points are separately measured (if they exist), and then the score sheet gets the data entered to help produce a picture of the symmetry and mass for each antler set.
Archery minimum score for the Pope and Young Club is 125 for typical deer antlers, and 155 for non-typical deer. As a rule, a white-tail needs to have 15 inches or more of non-typical point totals to determine if it will score higher in the non-typical category. Non-typical inches are added back to the basic antler frame measurement totals.
Boone and Crockett minimums for white-tails are 160 to receive an award and 170 to go into the all-time lineup. Non-typical whitetail minimums are 185 and 195, respectively.
Coming up soon, on March 1, 2 and 3, 2024, is the Iowa Deer Classic Show at Hy-Vee Hall and convention center in Des Moines. Some of Iowa’s best white-tail deer heads and antler sets will be on display for the public to observe, and the show features all kinds of other hunting opportunities, not just deer, and all the gear required to help improve your future deer hunting excursions.
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Deer harvest numbers, so far, with all regular seasons over, and few special late seasons in select spots of Iowa remaining, shows a total Iowa deer harvest of 100,756 as of last Wednesday. Of those, about 47,000 plus were female deer, and another 53,000 plus were male deer.
Marshall County deer hunters during archery and gun seasons took about 560 deer.
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A gift for yourself, or other nature enthusiasts is a park atlas. It is published by the Marshall County Conservation Office. The atlas features descriptive photo maps and an index to all public areas in Marshall County.
There are parks, wildlife areas, fishing areas, river access sites, refuges and many public hunting areas. There are wetlands, native and/or reconstructed prairie grasslands, and forested lands. Green Castle has an enclosure that holds a small American Bison herd. They are behind a safe fence, to protect them from wandering, and to keep the public safe from these seemingly ‘domestic’ animals — which, in truth, are still wild and unpredictable.
And of course, there is the Grimes Farm and Conservation Center, where educational programs for all ages are presented, and wildlife dioramas depict species of our forest, prairie and wetlands. The park atlas cost is $10. Purchase your copy by stopping by the Grimes Farm.
The atlas can be your guide to local outdoor adventures. Enjoy.
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Garry Brandenburg is the retired director of the Marshall County Conservation Board. He is a graduate of Iowa State University with a BS degree in Fish & Wildlife Biology.
Contact him at:
P.O. Box 96
Albion, IA 50005
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- PHOTOS BY GARRY BRANDENBURG — Bald Eagles have great vision. And great vision allowed at least one eagle to spot a dead deer, killed by a vehicle strike most likely, not too far from the road shoulder off highway 330 northeast of Albion. The date of these images was Jan. 7, 2024, just prior to the onset of our first big snow storm of the winter. Once the deer carcass was located, many other eagles were quick to spot the buffet line of opportunity. When this author observed the ‘crowd,’ with most just waiting for their turn, there were at least 12 eagles, both immature and mature, sitting in the bean field. My long lens was put to good work recording images of a predator/prey interaction. The transfer of nutrients and energy that once supported the life of the deer is now supporting the life of many eagles. It is nature in action.
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