While it's tragic and alarming to see a massive die-off, it's not uncommon for birds that travel in such large populations.

Dozens of dead and sick birds are washing ashore on Lake Michigan beaches in Illinois and Wisconsin, suspected of having the bird flu, according to state officials. The birds, typically Red-breasted and Common Mergansers,

The outbreak started in December and has now spread from a few reports in the suburbs to hundreds in the city, along Lake Michigan, over the last week.