What identification challenge do the drab coloration of females and young males sometimes present to observers?

Answer

They are occasionally mistaken for warblers

Because females and first-year males are colored a drab yellowish-green, they can sometimes be confused with warblers if they are not observed closely enough to see other identifying features.

What identification challenge do the drab coloration of females and young males sometimes present to observers?
raritybirdavianorioleorchard