Ever heard of a bird hibernating in a lake? Probably not, because birds don't actually do that. Nevertheless, hibernation was one of the theories that scientists had to describe where birds went during the winter before they understood migration patterns. Another leading theory was that birds migrated into space, spending those long winter months on the moon! So how did scientists figure out the truth to birds' migratory paths?
Around 1900 a scientist named Hans Christian Mortensen decided to band several birds in order to track where they went. When a white stork that had been banded in Hungary was found in South Africa, the mystery began to reveal itself. But it wasn't until 1984 when the first bird, a bald eagle in Maryland, was fitted with a transmitter that could send signals to satellites, allowing scientists to actually track the bird's whole migration, not just to points where it was found and captured.
With this modern technology, we have come to understand migration paths more in depth, and some of the migrations we have tracked are truly amazing. Take that of the Bar-tailed Godwit, who travels from Alaska to New Zealand, or 7,000 miles in only eight days! Or the Arctic Tern that travels from the North Pole to the South Pole - or 25,000 miles!