In May 1939, an experiment at the Bern Dählhölzli zoo featured colorful budgerigars freely flying in an open aviary, led by animal psychologist Heini Hediger. This study aimed to assess whether the birds would prefer the zoo or the wild. Despite some birds exploring nearby areas, most chose to stay, supporting Hediger’s theories on animal behavior and adaptation. His pioneering work in zoo biology significantly influenced the understanding of animals in captivity and their social dynamics.
A Surprising Experiment in the Bern Dählhölzli
In May 1939, visitors enjoying a leisurely Sunday walk through the Bern Dählhölzli, the forest home to the local zoo, encountered an unexpected sight. Amidst the familiar presence of deer and roe deer within their enclosures, colorful flocks of yellow-green and blue budgerigars soared through the air in a nearby clearing. These vibrant birds created a lively atmosphere, chirping and whistling as they flitted from bush to bush, displaying their playful nature.
One of the most astonishing aspects of this scene was the open aviary where many of these budgerigars resided. They came and went freely, raising the intriguing question of whether they preferred the comforts of the zoo over the wild. This captivating experiment was spearheaded by the ambitious animal psychologist, Heini Hediger, who had recently taken on the role of administrator at the Bern zoo, which had been established just two years prior.
Heini Hediger: A Pioneer in Zoo Biology
At only thirty years old, Hediger was already making waves in the field of animal behavior. His vision extended beyond the zoo in Bern; he would later take charge of the Basel Zoo in 1944 and then the prestigious Zurich Zoo a decade later, solidifying his reputation as a leading figure in the global zoo community. His influential book, “Wild Animals in Captivity,” published in 1942, became a cornerstone in the study of zoo biology, garnering translations and acclaim across various languages.
Hediger’s innovative idea of a free-flight experiment with budgerigars had been brewing for some time. After discussions with his animal keepers, he began receiving offers from the public to contribute birds for the experiment. While he declined an offer for cockatiels, he welcomed a donation of twenty pairs of budgerigars from Mr. Scheidegger, a local train station buffet owner. This sparked a critical inquiry: Would these birds choose to remain in the zoo or venture into the wild to establish new habitats?
As the experiment unfolded, Hediger meticulously banded each bird to track their movements, employing lightweight aluminum rings sourced from a local manufacturer. His colleague Hans Steiner, a fellow zoologist, had previously studied budgerigars’ genetics and provided valuable insights that enriched Hediger’s research.
Unlike many contemporaries focused solely on evolution, Hediger’s curiosity lay in the behavioral patterns of wild animals in captivity. He aimed to explore the concept of “space problem” and “flight distance,” understanding how animals perceive humans as threats and how this impacts their behavior in captivity. Hediger theorized that as the budgerigars adapted to their surroundings, they would create a sense of territory within the zoo and choose to stay as long as their basic needs were met.
In May 1939, Hediger put his hypothesis to the test by releasing the budgerigars into the open aviary. The following weeks revealed fascinating results. While some birds ventured beyond the zoo’s boundaries to nearby neighborhoods, the majority remained, proving Hediger’s theory about their acclimatization and loyalty to their new home.
Ultimately, this groundbreaking experiment not only showcased the adaptability of budgerigars but also paved the way for future research in animal behavior within zoological settings. Hediger’s insights into the lives of these colorful birds continue to resonate in the fields of ethology and zoo management today.