Wisconsin Wildlife Officials Continue to Monitor for Bird Flu in Nesting and Migrating Birds

Monday, June 5th, 2023 -- 11:00 AM

(Paul Smith, Milwaukee Journal Sentinel) As an historic outbreak of highly pathogenic avian influenza continues to circulate across most of the world this spring, wildlife officials continue to watch for signs of the disease among nesting birds and those migrating north as well as assist with efforts to develop a vaccine to fight the virus in endangered wild birds and commercial flocks alike.

According to Paul Smith with the Milwaukee Journal Sentinel, in one hopeful sign, preliminary data show eaglets are surviving at a higher rate this year in Wisconsin bald eagle nests, according to a project organized by Madison Audubon, potentially indicating the disease is waning.

Since it was detected in North America in the winter of 2021, the H5N1 virus has spread throughout the US, into Mexico and Central and South America. It’s been documented in every state except Hawaii and on every continent except Antarctica and Australia, although many wildlife disease experts expect it to arrive there, too.

The virus has also affected mammals, including grizzly bears in Montana. The outbreak is already the deadliest ever for U.S. poultry producers, affecting 58.8 million domestic birds, according to the U.S. Department of Agriculture.

It has surpassed the 2015 outbreak of subtype H5N2 which hit about 49 million birds at U.S. farms. At a cost of $1 billion, that outbreak was deemed the most costly animal health emergency in U.S. history, according to the USDA.

The financial losses associated with the current bird flu strain have yet to be tallied, but are likely to exceed the previous outbreak. The toll on wild birds is much more difficult to assess. However, all signs point to the outbreak of H5N1 over the last two years as the deadliest version of bird flu ever documented among wild birds.

Feel free to contact us with questions and/or comments.