This is a category for birds that are only known from fossil evidence or oral traditions.

Several early taxa are not unequivocally classified as birds or dinosaurs; for these, both inclusion in this category and Category:Feathered dinosaurs is feasible. As soon as a taxon is generally accepted to be a bird or a dinosaur, it should only be listed in one of the aforementioned categories as appropriate.

A note on the use of subcategories and page listings:

A page should be listed here if it deals with:

• a taxon above the rank of genus
• a genus or species which occurred over several geologic periods or epochs.

Other genera, species and subspecies should be listed under the appropriate subcategory.