Foraging with the Horned Guan
By Ellen S. Dierenfeld, Staff Nutritionist and Michael Macek, Curator of Birds
The horned guan (or Pavon) lives in the mountain pine/oak forests of southeastern Mexico and Guatemala. By the early 1930s, logging, coffee farming and hunting had greatly reduced the numbers of this spectacular species. Today, less than 1,000 birds exist in the wild and the Pavon is listed by The World Conservation Union as critically endangered. The Saint Louis Zoo is currently making an effort to study the nutritional habits of the guan to aid in the conservation of this rare bird.
In March 2006, Michael Macek, Curator of Birds and Director of the Center for Conservation of the Horned Guan in Chiapas, Mexico and Dr. Ellen Dierenfeld, Staff Nutritionist at the Saint Louis Zoo, embarked on a ten-day field exploration to the cloud forests of El Triunfo Biosphere Reserve in Chiapas, Mexico. The trip focused on obtaining samples of native foods eaten by horned guans - a highly endangered species of bird - for nutritional analysis. This trip was funded in part by a WildCare Institute Field Conservation Grant in order to aid in the survival and protection of this feathered species.
Partner participants included Fernando Gonzalez Garcia of the Instituto de Ecologia A.C. in Xalapa, Veracruz, and Gretel Tovar, a four-year veterinary student at the University of Mexico, who has been conducting zoo feeding trials with horned guans in three Mexican zoos under the supervision of Juan Cornejo, Curator of Birds, Africam Safari (Puebla, Mexico) as part of the grant study.
Participants hiked approximately 60 miles over the course of six days at altitudes ranging from 6,000 to 8,000 feet. Starting at a now abandoned shade coffee plantation, the team hiked approximately 10 miles to their base camp at El Triunfo. During this period, eight horned guans were observed and vocalizations recorded. Two pairs of birds were sighted. The crew even witnessed a male feeding a female as part of the birds' courtship ritual.
Leaf and fruit samples were collected from 15 of the most important food plants in the horned guan's breeding area. Fruits ranged from wild mulberries to small avocado types. Fresh samples were screened for secondary compounds - alkaloids and tannins - in the field lab, while preserved samples were sent to the Instituto de Ecologia, A.C. for further analysis. Feeding trials on captive guans are also being completed in three Mexican zoos: ZooMAT in Tuxtla, Leon Zoo and Africam Safari.
The combined data of these studies will provide the first analysis of digestive physiology of this highly endangered species, leading to a better understanding of the nutritional resource and habitat needs for these beautiful creatures.
The Saint Louis Zoo has also developed the Horned Guan Conservation Center to serve as the leading U.S. organization dedicated to the conservation of the Pavon and its habitat. This center will help to initial local education programs. These programs coupled with enforcement action will help reduce the threats caused by illegal timber removal and hunting. The reduction of coffee plantations and the formation of additional reserves can provide potential for eco-tourism resulting in alternative economic opportunities for local communities. The role the guan plays in the regeneration of montane forests is of paramount importance, and the Saint Louis Zoo strives to ensure the survival of this species through its Conservation Center.