Aythya valisineria x americana Status: Accidental in spring Record: The only record is of an adult male at Glenn Cunningham Lake, Douglas
Ring-necked x Tufted Duck (hybrid)
Aythya collaris x fuligula Status: Accidental in summer Record: A drake was photographed in Cherry Co 10 Jul 2019 (Paul Timm, eBird.org).
Mallard x American Black Duck (hybrid)
Anas platyrhynchos x rubripes Status: Rare casual winter visitor Records: There are two documented records: 4 Jan 2020