I know that you can think of some thing.
Fossil evidence helped prove the theory of continental drift because similar fossils could be found on separate continents, in rocks of roughly the same age, surrounded by layers that matched each other, and in some cases, found nowhere else in the world.
Examples include Mesosaurus and Lystrosaurus. Both are reptiles found in places now separated by oceans. Neither could have swum such great lengths across salt water.
Another example includes the plant Glossopteris, a fernlike plant from about 250 million years ago. That plant has been found in small areas in Africa, South America, Australia, India, and Antarctica, all in small sections that lined up in Alfred Wegener's (the guy who developed the theory of continental drift) view of the supercontinent Pangaea. It should be note that those other fossils also lined up too. Glossopteris has a seedlike structure to it that was too large to be carried such great distances by wind and not strong enough (too fragile) to survive a trip by water. You ask what about birds? That's quite a distance for a bird to travel while carrying a large seed.
All of this together, along with evidence from landforms that matched up just like the fossils, and evidence from climate helped convince Wegener that continental drift had happened.
