A bird's eyes interact with its brain in a region called “cluster N”, which probably helps the bird determine which way is north. Tiny amounts of iron in the neurons of a bird's inner ear also help in this determination. Most surprisingly, a bird's beak helps contribute to its navigational ability.

How can birds navigate so well?

Birds may use similar chemical reactions in their retinas, where photochemical reactions could lead to nerve signals which help them to orientate." Scientists have shown that animals can use a variety of cues to help them migrate long distances and return to the same breeding or feeding grounds.

Why do birds make the return journey?

Migratory birds fly hundreds and thousands of kilometres to find the best ecological conditions and habitats for feeding, breeding and raising their young. When conditions at breeding sites become unfavourable, it is time to fly to regions where conditions are better.