Wisconsin DNR announces necropsy results for snowy owl found dead in New Glarus

Madison, Wis. – The Wisconsin Department of Natural Resources (DNR) on Wednesday announced the necropsy results for a snowy owl recently found deceased in New Glarus.

When the owl was found dead on Feb. 5, 2025 in New Glarus, there were no apparent signs of the cause of death. A DNR conservation warden collected the carcass so that it could be submitted to the National Wildlife Health Center in Madison for necropsy and diagnostic testing.

The most pronounced findings from necropsy were emaciation and numerous intestinal worms that impacted nutrient absorption, resulting in emaciation. Heavy loads of intestinal worms are fairly common in birds of prey, with some individuals particularly susceptible due to genetics, immune status or feeding habits.

Avian influenza was tested for but not detected.

MORE COVERAGE FROM WISCONSIN OUTDOOR NEWS:

New York stripers on the fly just what the doctor ordered

A day behind a beagle hunting bunnies is hard to beat

Christine Thomas: Running with the ‘red bulls’ is great fun

This owl’s accessible location, small territory and diurnal activity drew dozens of visitors daily, ranging from casual onlookers to avid wildlife photographers. Some sought their first snowy owl sighting, while others hoped to capture their best images of this charismatic and often-elusive migrant from the Arctic.

Its popularity ultimately raised concerns about the owl’s welfare, as some feared that too many observers had negatively impacted its ability to survive.

Despite no indication that human disturbance was involved in the owl’s death, this case highlights that looks can be deceiving. For most of its stay, the owl seemed to be doing fine, with many anecdotes of it being active and catching prey.

It did not appear to be starving. Yet, it was, for at least the final stages of its life. Moreover, the owl often allowed a close approach, suggesting it may have been trying to conserve limited energy reserves.

Survival for wild animals is a challenge, even without humans. Disease, predation, injury, weather, unfamiliar territory and inexperience are all natural factors that can lead to death.

Human-related causes, like vehicle collisions, secondary poisoning and electrocution, greatly amplify the toll for snowy owls that visit Wisconsin and other southern latitudes in winter.

The result is a mortality rate approaching 80% for snowy owls in their first year of life, as the New Glarus bird was, based on its feather patterns. 

The public can help snowy owls and other wild animals survive in a challenging environment by understanding their needs and giving them the time and space to conduct their daily activities naturally.

Visit the DNR’s Keep Wildlife Wild webpage for tips on deciding if a wild animal is in need of help.