It's springtime, and some 350 bird species will be winging their way to summer homes for the nesting season. How do they know where to go?

There’s still much to learn about how a bird’s brain works to guide it from point A to point B, especially when you’re talking about distances of hundreds or even thousands of miles. What we do know is that there are two things researchers have identified as important to a songbird’s inner GPS: vision and scent.

Scent is a surprising one, because we don’t always think of birds as having a sense of smell. As it turns out, scent plays a critical role in helping birds find their way around. In a famous 1972 study of homing pigeons, there were two sets of pigeons released, one that could smell and one that could not. Both were released from an unfamiliar location and the pigeons that could not smell were not able to find their way home, versus the ones were able to could. Scientists call this olfactory mapping, and because they don’t know yet which specific odors are relevant to birds, this opens a new realm of scientific discovery.

A bird can also visually detect magnetic fields, which provides them with a visual compass to guide their journey over long distances. Changes in the magnetic field are visible to birds, and the further you travel from the equator, the stronger it gets. How does it work? Scientists have identified a protein in the eyes of European Robins and Zebra Finches they believe makes the magnetic field visible to birds. (If you want to see a visual representation of how it appears to a bird’s view, click here and scroll down until you reach the series of images above the diagram of a compass.)

Scientists have put these navigational abilities to the test. For example, in one experiment, Russian researchers captured Eurasian Reed Warblers along the Baltic Sea before the birds could depart to their breeding grounds to the northeast, and transported the bird 600 miles to the east. When the warblers were freed, they were able to reorient themselves, and they set off to the northwest.

During migration, birds will be traveling a long way. You can help by giving them a safe place to refuel with a mix that has plenty of seeds, nuts and fruit. Lyric Fruit & Nut High Energy Mix serves up an energy-rich blend of fruits, seeds and shell-free nuts.