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DNR: Nutritional deficiency to blame for dead and sick Canada geese on Iowa River

Canada geese tuck their heads back to stay warm while lying on ice formed on the Cedar River in Cedar Rapids on Sunday,
Canada geese tuck their heads back to stay warm while lying on ice formed on the Cedar River in Cedar Rapids on Sunday, Feb. 14, 2021. (Andy Abeyta/The Gazette)

CORALVILLE — A nutritional deficiency following a long winter is thought to be causing dozens of geese to get sick or die on the Iowa River.

More than 100 Canada geese and at least one mallard were found sick or dead near the low-head dam by the Iowa River Power Restaurant on the Iowa River since first reported to the Iowa Department of Natural Resources last week, according to DNR State Wildlife Veterinarian Rachel Ruden. The sick geese were showing neurological symptoms were and taken to wildlife rehabilitators, Ruden said.

DNR staff have been working to determine the cause of the sickness.

“At this time, on-site observations, gross findings on necropsy and clinical signs are highly suggestive of a nutritional deficiency exacerbated by the severe winter weather we have been experiencing across the state,” Ruden said in an email.

Ruden said the geese and ducks in the area were seen eating a shad, a fish with high levels of an enzyme known as thiaminase. She said high-shad diets have been linked to thiamine — or vitamin B1 — deficiencies in other species. That deficiency can lead to impaired brain function and death, Ruden said.

“We are waiting on additional diagnostics to confirm this diagnosis, but we anticipate the situation on the ground to improve as temperatures warm and waterfowl regain access to other food sources and foraging sites,” Ruden said.

Comments: (319) 339-3155; lee.hermiston@thegazette.com

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