Director Lee Jackson says they first heard about it in early February, and began preparing.
"So because we heard about this in late winter, some of those birds we just didn't put back outside and a few birds that were still outside, we moved in."
The zoo has about 100 individual birds, representing 21 species, ranging in size from finches to parrots and ostriches.
In addition, Niabi has stopped using any poultry products to feed its animals.
"And we have protocols in place for what to do if we find a wild bird dead in the park, and basically any bird that we find dead, whether it's a collection bird or a wild bird, gets sent to the University of Illinois for testing."
Jackson says the zoo has a relatively small collection of birds, after letting the numbers fall slowly in recent years, and now he's glad they did.
Opening day for the new season is still set for April 18th.