Researchers are increasingly exploring alternatives to traditional laboratory animals to gain deeper insights into the human brain. According to a recent scientific review, birds may offer valuable insights into human mental disorders, particularly those related to stress, mood, and cognition.
For decades, neuroscience research has relied heavily on rats and mice. However, these animals are relatively easy to study and manipulate experimentally; they lack some complex behaviors that are highly relevant to human mental processes. In contrast, birds exhibit sophisticated behaviors that more closely parallel aspects of human cognition and emotional regulation.
One notable example is long-distance migration and navigation, which involve stress regulation, emotional control, and decision-making. These behaviors are widespread among birds and do not exist at all in small rodents. Millions of migratory birds travel annually between breeding and wintering grounds, guided by internal biological clocks and external environmental cues.
The duration of daylight or the photoperiod is the primary control of migration timing. This process tightly coordinates hormone levels, such as thyroid hormones and gonadotropin-releasing hormone. Interestingly, other hormonal systems are also present in humans and are already used in the treatment of mood disorders through interventions such as light therapy, melatonin-based drugs, and thyroid hormone supplementation.
Unlike migration timing, migratory routes are flexible. Studies show that birds can alter their flight paths depending on experience and social interactions. For example, a case study of pink-footed geese documented the establishment of a new breeding ground in Novaya Zemlya, and the count of the birds rose to 3,000 in spring and 4,000 in autumn over 10 years. These findings suggest that cognitive and emotional processing play a major role in navigation, offering potential parallels to human behavior and mental health.
The other amazing skill of birds is magnetoreception, the ability to sense Earth’s magnetic field for orientation and navigation.  This ability relies on two biological mechanisms: cryptochrome proteins located in the retina and magnetite particles that detect magnetic field intensity. The magnetic field of the Earth might also be insufficiently sensitive to humans, yet the connection between health and illness is debatable. Studying magnetoreception in birds may help clarify whether subtle magnetic sensitivity affects human well-being.
Another interesting aspect of birds is their higher level of thinking. Certain species are problem solvers, particularly crows and ravens, suggesting forms of higher-order cognition and possibly consciousness. Despite having brain structures that differ substantially from those of mammals, birds show functional similarities at the neural circuit level. This makes them valuable models for studying cognition, emotional regulation, and potentially consciousness-related aspects of mental disorders.
One of the brain systems that has been highlighted in the review is the dorsal diencephalic conduction system (DDCS) that incorporates the habenula. The habenula in humans is very small, with a size of 15-30 mm 3 on either side, but it plays a crucial role in regulating mood, motivation, anxiety, and addiction. Due to its small size and complexity, the DDCS is difficult to study directly in humans.
Birds can assist with these limitations; however, another useful model is the lampreys, a primitive vertebrate whose brain organization resembles that of early vertebrates from approximately 560 million years ago. The DDCS is comparatively large and simpler to investigate in lampreys. The integration of the works from lampreys, birds, and humans may provide deeper insight into how the ancient neural circuits contribute to modern mental disorders.
In conclusion, this review suggests that expanding mental health research beyond traditional mammalian models may open new avenues for understanding the biological basis of mental illness. Investigating migration, navigation, emotional regulation, and cognition in birds and lampreys could ultimately lead to more precise and effective therapeutic strategies for human mental disorders.
References: Loonen AJM. Birds may represent a useful animal model for studying human mental disorders. Acta Neuropsychiatrica. 2025:1-32. doi:10.1017/neu.2025.10045
