A great find! Roseate Spoonbills are certainly capable of long-distance vagrancy, it's just that they don’t make it this far very often.
These back-to-back sightings remind me of driving all the way from Nekoma to Melvern Res. on 1 Sept 1986 to see a very distant Roseate Spoonbill (found by Marvin Schwilling if memory serves) by looking west from the Hoch Road causeway. A mere 500 mile trip for me, an absolutely brilliant decision on my part. However, I felt considerably less wise five days later on 6 Sept 1986 when Ted Cable and I saw another Roseate Spoonbill sailing over the Nature Conservancy area NW of Cheyenne Bottoms, just 30 miles from my house.
From: Birds & Their Habitats in Kansas [mailto:<KSBIRD-L...>] On Behalf Of Nick Varvel
Sent: Monday, August 28, 2017 9:11 PM
Subject: Re: Roseate Spoonbills
A pretty nice photo of the spoonbills was added to eBird. Wacky stuff.