Scientists uncover the genetic secrets of bird navigation

The Yellow-bellied flycatcher (Empidonax flaviventris) is a small insectivore of the tyrant flycatcher family that cannot produce the protein cryptochrome 4. The birds breed in North America and migrate to southern Mexico and Central America in winter. Credit: Carl von Ossietzky-Universität Oldenburg

Researchers have been unraveling the secrets behind how migratory birds navigate with remarkable precision across vast distances.

A team of scientists led by Dr. Corinna Langebrake and Prof. Dr. Miriam Liedvogel from the University of Oldenburg and the Institute of Avian Research “Vogelwarte Helgoland” has made significant strides in understanding this phenomenon.

Migratory birds use a natural “compass” in their eyes, which helps them detect Earth’s magnetic fields.

This compass is thought to be a specific protein called cryptochrome 4, found in the birds’ retinas.

The team’s recent studies, including their latest published in the journal Proceedings of the Royal Society B: Biological Sciences, have provided further insights into this intriguing biological feature.

The researchers analyzed the genetic makeup of over 360 bird species, ranging from tiny song sparrows to the exotic kiwi.

They discovered significant changes in the gene that produces cryptochrome 4, showing that this gene has evolved differently in various bird species.

Some birds, like robins, which are known for their long migratory journeys, have a highly sensitive version of this protein, allowing them to sense magnetic fields more effectively than birds like chickens or pigeons, which do not migrate.

In contrast, other bird species such as parrots, hummingbirds, and some tropical birds known as Tyranni have completely lost this gene.

This raises fascinating questions about whether these birds have developed a different mechanism to navigate or if they can manage without a magnetic sense at all.

The study also compared cryptochrome 4 to other related proteins involved in regulating the internal clock of birds.

These proteins have remained largely unchanged through evolution, highlighting their crucial role in maintaining daily rhythms essential for all bird species.

However, cryptochrome 4 has evolved variably, suggesting it has adapted to meet the specific environmental challenges faced by different birds.

One intriguing aspect of the research is the study of birds that lack cryptochrome 4. The Tyranni, for instance, despite some being long-distance migrants, do not have this protein.

This presents a unique opportunity to explore alternative navigation methods or to confirm if these birds can indeed navigate without a magnetic sense.

Looking ahead, the research team plans to delve deeper into the magnetic orientation abilities of these birds to better understand the function of cryptochrome 4 and its importance in bird migration.

This ongoing research not only sheds light on the fascinating world of bird navigation but also helps us appreciate the complex interplay of genetics and behavior in wildlife.

Source: KSR.