a simple prop

Okay. So, last weekend I was out shopping. The nearest major body of water was the Ohio river, about 20 miles away. While I was in this suburban shopping center in southwest Ohio, I looked up to see two birds that had the coloration of typical gulls but the body forms and flight style of falconiformes. They were extraordinarily lovely, and I was without a clue.

Based on the description of E. leucaris I found, these two birds were superficially similar, but they were well outside the range where these birds are found. Does anyone have a clue what I might have seen? (I’ve seen some lovely birds since I moved to this part of North America, but nothing like this pair of white-and-black falconiform birds circling over a suburban shopping center.)