Any bird out of place seasonally or geographically, no matter how common the bird is elsewhere or at other seasons or easy the identification.
Notes written later, and particularly after a field guide has been checked, are much less credible.
Notes that read like a field guide are even less credible. The notes should be made before any field guide is checked. At this point getting a good unbiased description is much more important than putting a name on the bird. If your notes are good enough you will be able to name the bird after it has disappeared. And that is how reviewers will judge your notes.