The fossil record is put together from evidence stored 1. under the right conditions and 2. found mostly by chance. It's not surprising there's nothing in the fossil record for a long time, although we can usually support that from something else in another part of the world.
And no, I'm afraid you're misinformed when you say "it's a bird or it's not." We've got a bunch of transitional birds. Sinosauropteryx prima is covered in feathers, but is shaped just like other little raptor dinosaurs at the time. Microraptor has feathers here and there. Our definite "early bird" Archaeopteryx was actually *more* lizardlike than some of those. . . here, have the whole list in source.
And some other transitional forms while I'm at it, second link.
I'm also confused how you can say Neanderthals were human. They were behaviorally different from us, which is part of what led to their extinction--they were slower and more cautious to explore while we ran rings around them. Their genes are also quite different, and it's very unlikely that a Neanderthal and a human ever had a child who could have children.