What you need to know about bird flu. Public health experts are closely watching avian influenza, which has affected chickens and cows and sickened some Americans.

Nearly 119,000 birds have been culled at a farm in California after a bird flu called H5N9 was detected among the poultry

After multiple recent reports of ducks and geese washing up dead on Chicago's lakefront, Illinois wildlife officials tell Axios they believe the deaths are the result of a bird flu resurgence caused by warmer weather.

The infected birds "present with tremors and little ability to move," said a local conservation group tracking the outbreak.

Monitors with an area bird tracking organization say that they've determined that a number of ducks have succumbed to bird flu​ along Lake Michigan.

Monitors with an area bird tracking organization say that they've determined that a number of ducks have succumbed to bird flu​ along Lake Michigan. Marissa Sulek reports.

Officials urged residents of the Chicago area not to touch -- or let their pets touch -- dead or sick birds as a bird flu outbreak sickens and kills many across the region.