Testing has confirmed that HPAI was the cause of death for Teal, a Chilean flamingo chick, on Jan. 8; and Slater, a harbor seal, on Jan. 9, according to a news release. These are the first known cases of the virus at this zoo.

Their deaths came within a day of each other, the Chicago zoo said in a Jan. 15 news release. Teal, a months-old Chilean flamingo, died Jan. 8 and Slater, a 7-year-old harbor seal, died Jan. 9.

A harbor seal and a Chilean flamingo died from the bird flu this month at the Lincoln Park Zoo in Chicago, officials said. The flamingo died January 8 and the seal died January 9, the Lincoln Park Zoo said.

CBS News Chicago spoke to a wildlife expert at Anderson Humane in South Elgin. She said waterfowl like geese are among the main spreaders of bird flu.

The sources of exposure are unclear, but officials said it was almost certainly from contact with an infected waterfowl.

The Chilean flamingo, named Teal, hatched last fall and died Jan. 8. The 7-year-old harbor seal, named Slater, died the next day. Zoo officials say it was “near certain” that the disease derived from contact with a waterfowl that was infected with the virus.