Understanding Hyperphagia and Migration in Swainson’s Hawks: Our Experience with Gaucho, Our Ambassador Bird

Understanding Hyperphagia and Migration in Swainson’s Hawks: Our Experience with Gaucho, Our Ambassador Bird

Migration is one of nature’s most awe-inspiring phenomena, and for many birds, it’s an essential part of their life cycle. For long-distance migrators like Swainson’s Hawks, preparing for migration requires intense metabolic changes, with one of the most crucial being hyperphagia. This term describes the period of rapid, increased feeding that birds go through just before their migration. With Gaucho, our non releasable ambassador Swainson’s Hawk, we got a unique, up-close look at how hyperphagia influences a migratory bird’s behavior—even when that bird isn’t going anywhere.

What Is Hyperphagia?

Hyperphagia is essentially a period of intense “fuel loading” in which migratory birds consume far more food than usual. For Swainson’s Hawks, who travel from North America to as far south as Argentina, building up fat reserves is critical. This fat serves as a high-energy resource that sustains them through thousands of miles of flight, often across areas with limited access to food.

During this time, their appetite significantly increases, allowing them to bulk up on energy reserves. This physiological process isn’t just a slight appetite increase—it’s a necessity for survival. Without it, these birds wouldn’t have the energy to reach their distant wintering grounds or return to their breeding grounds when the time comes.

Bar tailed godwits, for example, a shore bird that has breeding grounds up in Alaska, hold the record for the longest nonstop flight of any bird, traveling over 7,500 miles (12,000 kilometers) from Alaska to New Zealand without stopping to eat, drink, or rest! To make this journey, bar-tailed godwits rely heavily on hyperphagia, devouring vast amounts of food to build up their energy reserves, which they store as fat. In doing so, they nearly double their body weight, feasting on protein-rich marine worms, mollusks, and small crustaceans.

Migration is so intense for bar tailed godwits that they do something truly remarkable. This feeding period must add enough fat to sustain their entire flight across the Pacific Ocean. During hyperphagia, they prioritize fat storage so much that they actually shrink some of their nonessential organs, like parts of their digestive system, to reduce their body weight and conserve energy for flight.

Working with Gaucho: Hyperphagia in Action

Our team was reminded of the intensity of hyperphagia as we prepared Gaucho, a non-releasable Swainson’s Hawk, for his debut as an education ambassador. While he won’t migrate due to his injuries, his instincts and biology remain intact, especially as fall approaches. Like his wild counterparts, Gaucho began to show signs of hyperphagia, consuming much more food than usual and exhibiting behaviors driven by the instinct to prepare for migration.

This was a unique challenge for us as trainers. We had to balance Gaucho’s natural urge to consume large amounts of food with the need to manage his weight and maintain his readiness for training. Since Gaucho couldn’t just fly off those extra calories as a wild bird would, we had to be mindful about how his diet was structured to avoid weight gain that could affect his health and training responsiveness.

Training Gaucho for His First Education Event

With Gaucho’s first event coming up, we wanted to ensure he was not only prepared to engage with the public but also comfortable and healthy. His diet and training plan were carefully adapted to support his natural feeding drive while maintaining his fitness and focus. We provided regular mental and physical enrichment to channel his energy and mimic the natural foraging behaviors he’d experience in the wild. Training him to perform simple behaviors like hopping onto his perch or flying a short distance to a glove also helped burn off some of that extra energy in a controlled, safe way.

We also found that incorporating this natural period of hyperphagia into his training routine allowed us to build trust with Gaucho. He learned that we would always provide for his needs, which, in turn, strengthened his engagement with us. This process took patience, but it was rewarding to see Gaucho develop more confidence in himself and in us.

Bringing Gaucho’s Story to the Public

At his first education event, Gaucho was a star. Sharing his story allowed us to educate others not only about the unique journey of Swainson’s hawks but also how this bird links continents and whole hemispheres together. Through Gaucho, we were able to share the intricate needs of migration, helping the public understand just how specialized and resilient these birds are.

As the audience learned, Gaucho represents both the challenge and beauty of balancing natural instincts with human care. His journey from rehabilitation to becoming an ambassador showcases the dedication it takes to honor a bird’s natural behaviors—even when he can’t migrate himself.

Working with Gaucho has shown us how adaptable and powerful migratory instincts can be. Hyperphagia may seem like just an increase in appetite, but it’s actually a vital survival strategy that allows birds like Swainson’s Hawks to undertake one of the most remarkable journeys in nature. Through his story, Gaucho helps connect us all a little more to the natural world, reminding us of the incredible journeys animals undergo every year.

Thank you for following Gaucho’s journey! We’re honored to help share his story and continue learning from him every day. Come meet Gaucho in person at any of our upcoming experiences and witness firsthand the resilience and adaptability that make Swainson’s Hawks so extraordinary.