Hey guys, I found this button a month or two back. Looks like a skinny eagle with a ribbon in its beak, also appears to have a shield near its breast. Button is cuff size with a Scovill MFG' Co Waterbury backmark
The button you found is a post-civil-war (Indian Wars) era Illinois State Militia officer's button. It shows the 1868-&-later version of that state's seal. See button IL-1A1 in the button book by Alphaeus H. Albert.