Found this today on the IBET (IL Birders Exchanging Thoughts) message board concerning a baby least tern being adopted by a snowy plover.
Here is the site: http://birdphotographers.net/forums/showthread.php?t=40445
The IBET posting is at ILbirds@yahoogroups.com. May need to enroll to the list for access. It is very informative on Illinois birding. I used a lot of information from watching this to locate
knowledgeable birders and the best locations for my visit to the Chicago area. Good grassland species to be found. I had around 20 lifers on my visit.