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Eagle watching — Who is watching who?

Photo by Garry Brandenburg — Bald Eagle pairs are busy with eagle nesting duties. The time line started last fall with pair bonding. Now in mid February a nest site has likely already been selected, a new nest built, or a former nest remodeled, to prepare for mating and egg laying later this month. Egg laying can happen at the end of February. Eaglets hatch in late March or early April. There are approximately a dozen known eagle nests in Marshall County going into 2021.

EAGLE NEST WATCHING by people may be a later winter activity for some folks. Congratulations if you are one of those people inspired by this annual wildlife renewal story being played out near you. If you know where to look, an active eagle nest is not too far away from wherever you live. Observe from a distance with binoculars or a spotting scope. Enjoy your eagle observation forays.

We are fortunate to have the Decorah eagle nest site camera up and running. By simple computer clicks, one can watch eagle goings-on anytime of the day or night, rain or snow, wind or clear blue skies. In fact somewhere in the world people are tuned in to the Iowa eagle nest observation site. That is nice to have. The camera system is set up and maintained by the Raptor Resource Project, a non-profit organization for the preservation of falcons, ospreys, hawks and owls and eagles.

Statewide eagle nesting territories that are known is nearly 400. Perhaps not all of these are active, most are however. An average of between one and two eaglets survive to fledgling stage. This could result in 800 to 1,200 new eaglet chicks hatching by early April. Biologists estimate the statewide overall nest success rate at 1.38. Experienced pairs with lots of knowledge inside their eagle brains can successfully hatch and raise three baby eagles to flight status. The female eagle at Decorah’s camera nest site was estimated to be 17 years old in 2020. She now will be going into year 18.

Several of the former young eagles from Decorah have been radio tracked by GPS technology. One of those stayed close to the nest site at first, then flew up the Mississippi River valley and continued its adventures all the way north to the sea shores of Hudson Bay in Ontario Canada. After a brief stay up north, the bird eventually flew back to the northeast Iowa vicinity. Good information on flight paths were obtained from little radio tracker devices.

Eaglets hatched at Decorah are assigned a number, such as D-20, 21 or whatever the current nomenclature reflects for an accurate count. Decorah eagles are not given names in order to prevent viewers from regarding them as pets.

“Traditional names can create an undue tendency to anthropomorphize. While the human emotions that may be attached to the eaglets are understandable, an alpha-numeric system for referencing them may help us distance ourselves to observe the wonder of wildlife and nature at work.”

WARMER WEATHER is a welcome change for us. We will enjoy it while it lasts. After our deep freeze reminder from Mother Nature of what she can do when the high altitude jet stream oscillates far to the south, our more “normal” winter weather pattern returns. It is typical every winter to have a cold spell and a warmer time within the winter season. Snow cover can melt a bit, and give us reassurance the spring season is on the way.

With a temporary February thaw, water will find its way into waterways, small streams and eventually to the Iowa River. The pressure of new water inflow will raise those thick layers of river ice. As more and more water enters the river, ice will weaken, slowly at first, and eventually break up. This author has observed fast river ice breakups and slower more moderate ice decay times. A short thawing time frame with night time freezing temps may make the entire river ice spectacle a non event. And of course there have been past years when the thaw was longer lasting, runoff from snow cover was rapid, the river became swollen beyond capacity quickly, and the result was lowland flooding.

A factor in river ice breakup are restriction points where ice blockages may occur, usually at bridge abutments. Once an ice jam begins, all the resulting ice floating from upstream cannot pass. So it just piles up, crashing into each other to make an even larger restriction. It gets worse. Flowing water under these ice chunks does not stop. It keeps flowing and constantly looking for escape avenues under or off to the sides of the ice jam. That is when low land flooding happens quickly.

A frequent example of just Bald Eagle pairs are busy with eagle nesting duties. The time line started last fall with pair bonding. Now in mid February a nest site has likely already been selected, a new nest built, or a former nest remodeled, to prepare for mating and egg laying later this month. Egg laying can happen at the end of February. Eaglets hatch in late March or early April. There are approximately a dozen known eagle nests in Marshall County going into 2021.

one ice jam scenario is from Timmons Grove downstream to the old railroad bridge about 3/4 mile to the east. This bridge has low level steel beams and a narrow passageway for water flow. Ice can get stuck here easily. When it does, an ice jam can begin, enlarge and grow even bigger. It is then possible for that ice jam to back up broken ice all the way upstream toward Stanley Mill bridge west of Albion. Water under that ice, and any incoming flow from all other area drainages, will cause floodplain lands to flood.

There is no way to predict with confidence how late February and March weather will affect, fast or slow, snow pack disappearance. All we can do is anticipate and adapt. What this author has seen and experienced in past times is a bit of each option. One year I recall thick ice chunks floated out of the active river channel into Timmons Grove County Park. And then those big flat 12 inch or more thick parcels floated in the flood water over-topping highway 330 north of the river bridge. Many of those huge ice chunks became high centered and stuck on the centerline of the highway, effectively adding another blocking mechanism to already high water. Highway crews had to dispatch large end-loaders to push those ice chunks into the east ditch. Time will tell how history books will record ice breakup this year.

PERMANENT ICE FISHING HOUSES on state waters had a mandatory removal date of Feb. 20. This is more common in Iowa’s Great Lakes regions such as Okoboji, Spirit Lake or Clear Lake among others. The reason for this regulation is the potential for weakened ice preventing removal of those structures. It has happened before that ice houses sank. Now the expense of removal falls on the ice house owner And it is not cheap to accomplish that task. Each winter season is different. If ice conditions do not weaken, a short time extension can be made. Still, it remains a reminder that ice fishing houses need to be removed soon.

IZAAK WALTON LEAGUE SCHOLARSHIP application for high school seniors, or already enrolled college students, desiring to study conservation or environmental course work at a college or university level, may wish to consider a scholarship application from the local Izaak Walton League. This is a competitive grant. It requires a demonstrated commitment that is backed up by grades and references. To review the application, one can go to the local Ikes website which is marshalltownikes.com/scholarship.html. Applications must be received before March 15. Send completed applications to PO Box 327, Marshalltown, IA 50158.

Here is a wish for 2021: We have all heard about a “fountain of youth.” Let’s replace that with a “fountain of smart.”

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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