There’s a colorful new resident on the Tropics Trail – and his feathered wings are possible because of the Minnesota Zoo’s commitment to collaboration.

The Minnesota Zoo is home to a breeding pair of Rhinoceros Hornbills that successfully hatched their third chick in May 2024. This bird species is threatened in its native tropical forests in Indonesia, Brunei, Malaysia, and Thailand.

Hornbills have an interesting nesting strategy in which the female is sealed in a tree cavity for 80 – 90 days with a single egg, and then the chick once it has hatched. The male feeds them through a small opening in the otherwise sealed nest. When the chick is about 45 days old, the female leaves the nest. Both parents and chick then reseal the nest, leaving only the small opening for food. The chick remains safely sealed inside, fed by both parents, until it is about 80 days old. The Zoo has a special behind-the-scenes area designed to facilitate this unique nesting process.

During this time, animal care staff at the Zoo monitor the nest closely, while allowing the parents to be the primary caretakers of the chick. However, this chick did not emerge naturally around the 80-day mark in July. Staff monitored overnight footage and saw the chick attempted to leave the nest but was unsuccessful. Recognizing this as an unusual sign, primary Zookeeper Christine Burns immediately investigated. She discovered the chick in the nest had stunted feather growth and damage to its flight feathers.

The Zoo’s animal care and animal health teams knew they must develop a special plan to support the chick during this critical stage of development when he should learn to fly.

After reaching out to colleagues throughout the country, the Zoo embarked on a procedure called feather imping which replaces damaged flight feathers with donated feathers from adult birds who naturally molted them.

Corryn Vitek, Senior Veterinary Technician with the Raptor Center, reviews imagery of hornbill wing pattern during a feather imping procedure at the Minnesota Zoo in September 2024.

All Hands on Deck

A five-institution collaboration emerged to help complete the process of imping. Molted feathers were donated by the Nashville Zoo and Virginia Zoo. These feathers supplemented those already on hand at the Minnesota Zoo.

Another collaborator was the Bell Museum, a natural history museum in St. Paul. Museum curators sent images of a Great Indian Hornbill male, whose remains were transferred to their collection several years ago after that bird lived out his life at the Minnesota Zoo. These photos helped the team choose the best feathers for the procedure.

Finally, technicians from the University of Minnesota Raptor Center completed the imping procedure at the Zoo. The Raptor Center is a world-renowned specialized hospital, wildlife rehabilitator, and research institution in St. Paul. Their staff replaced the chick’s wing and tail feathers with both Rhinoceros and Great Indian Hornbill feathers.

Donor feathers are placed on a rhinoceros hornbill chick to enable him to learn to fly.

Signs of success were immediate! Later in the same day of his procedure, the male chick was able to make short flights. He is flying more and more ever since and continues to strengthen his flight muscles.

In Full Feather

In early November, the Hornbill family moved from behind the scenes to their habitat on the Minnesota Zoo’s Tropics Trail. Now nearly as large as his parents, the chick is still growing feathers and working to increase his flight skills. By summer 2025, we anticipate the chick will go through his first molt process. The donated feathers will naturally molt, and new feathers will grow in their place.

The Minnesota Zoo thanks the Nashville Zoo, Virginia Zoo, Bell Museum, and Raptor Center for graciously assisting us in giving this chick the opportunity to spread his wings and fly.

Dr. Anne Rivas DVM, Jamie Toste, and Christine Burns with a rhinoceros hornbill chick following his feather imping procedure.

Helping Hornbills

With declining numbers, Rhinoceros Hornbills are categorized as Vulnerable by the International Union for the Conservation of Nature (IUCN). Habitat loss and hunting are outpacing their slow reproductive rate.

This species depends on sizeable tracts of undisturbed tropical forest in order to find large trees for nesting, and enough food for survival. Unfortunately, much of their original tropical forest habitat in southeast Asia has been harvested for timber and converted to cropland.

Rhinoceros Hornbills are also hunted for meat, tail feathers, and beaks. Their casques (the large, hardened structure on top of the beak) and tail feathers are used in traditional medicines and for ceremonial purposes. Poachers sometimes mistake them for Helmeted Hornbills. Unlike Rhinoceros Hornbills, Helmeted Hornbills have solid casques, which are more valuable than ivory. Additionally, Rhinoceros Hornbill chicks are captured for the pet trade.

One way the Minnesota Zoo supports hornbill chicks is through AZA SAFE Asian Hornbill, a collaboration of zoos working together to save these birds from extinction in the wild. That group in turn supports the Hornbill Nest Adoption Programme, an initiative of the Nature Conservation Foundation in India to monitor and protect dozens of nests of three hornbill species in the wild.

We also participate in the Rhinoceros Hornbill Species Survival Plan (SSP). By coordinating with other zoos across the country, we help maintain genetic diversity and increase successful breeding in the zoo and aviary population. The first successful hatch of a Rhinoceros Hornbill chick at the Minnesota Zoo occurred in 2018; a second chick hatched in 2023.

You can also help save Rhinoceros Hornbills and their tropical habitat! Here’s one of the easiest ways: choose food and household products made from sustainable palm oil. Palm oil is a common vegetable oil for cooking, but also an ingredient in many products used for cleaning and personal care. Rhinoceros Hornbills lose critical habitat for the creation of palm oil plantations. Sustainable palm oil is made with stringent guidelines that protect animals, people, and the environment.

This post was written by Jamie Toste, the Curator of Birds at the Minnesota Zoo since 2012.