Remembering Eric York 1970-2007

Many of Eric York's colleagues and friends throughout the National Park Service contributed to this memorial.

A Biologist's Biologist

With the passing of Eric York on November 2, 2007, Grand Canyon National Park lost an extremely talented and dedicated wildlife biologist. More importantly, the mountain lions, carnivores and other wildlife he studied lost one of their most knowledgeable and devoted human allies and advocates. Eric’s work, in fact his life, centered on his passion for wildlife, the outdoors, and grand landscapes of our national parks and other wildlands.

Eric York tracking lion with radiotelemetry.
Eric worked at Grand Canyon National Park as a wildlife biologist studying carnivore movement patterns from July 2006 until his death, and previously as a contract biologist starting in 2003. He previously worked for Santa Monica Mountains National Recreation Area in California, Lake Clark National Park and Preserve in Alaska, the U.S. Geological Survey Biological Resources Discipline and the University of California–Davis’ Wildlife Health Center on mountain lions and other large carnivores, specializing in livecapture techniques. Eric worked at Santa Monica Mountains NRA for more than 10 years and was critical to the establishment of their carnivore research program, which focuses on the ecology, behavior and conservation of bobcats and coyotes in that complex urban environment. In 2002, Eric initiated a project using global positioning satellite radio collars for the study of mountain lions in that park.
Eric (left) and a colleague, weighing a tranquilized mountain lion.
Eric (left) with a colleague, weighing a tranquilized lion.


Grand Canyon Lion Study

Beginning in 2003, the National Park Service participated in a radiotelemetry study of mountain lions within the Grand Canyon ecosystem to complement existing studies using remote cameras, track surveys, and scat and hair collection.

Eric’s skill with trapping techniques and compassion in handling captured cats was key to the successful implementation of the telemetry program that allowed collection of specific information about lion predation habits, reproductive activity and other behaviors.

An additional component of Eric's work for Grand Canyon’s Division of Science and Resource Management was his active collaboration with interpretive staff for outreach and education about his research on lions in the park.

This outreach, via ranger programs, site bulletins and the Grand Canyon Web page: still reaches thousands of visitors each year.

Pneumonic Plague

In 2007, Eric was monitoring collared mountain lions in and around Grand Canyon National Park, and also collecting data on bighorn sheep, black bear, bobcats, coyotes and other species. Two of the collared female lions produced litters in the summer, and Eric found the kittens, which he ear-tagged to incorporate them in the study. A few days prior to his death, he found the mother of one of these litters dead and recovered her body to perform a postmortem examination. Eric was a dedicated biologist who believed it was his responsibility to understand the cause of death for this female lion.

Eric became sick shortly after recovering the lion and performing the postmortem examination. The Centers for Disease Control and Prevention confirmed pneumonic plague as the cause of Eric's death. With the detection of the same strain of plague in the remains of the necropsied mother lion, the CDC concluded that Eric contracted the disease from the animal. Although plague can be transmitted to humans through the bites of rodent fleas, Eric's exposure likely came through direct contact with the infected lion. Plague is endemic in northern Arizona, but cases of pneumonic plague in humans are extremely rare. Eric's death reminds us of the inherent hazards, including the less obvious ones, that biologists are exposed to while working to manage and conserve wildlife.

As a result of Eric’s death, Grand Canyon National Park and the National Park Service Biological Resources Program implemented additional guidance to assist wildlife biologists in identifying risks and the appropriate work practices and personal protective equipment to make their job safer. NPS Safe Work Practices for Employees Handling Wildlife is a comprehensive document that provides detailed guidance that directs NPS employees in mitigating risks associated with handling wildlife so that important natural resource management and visitor protection activities can be performed in a safe manner.

In Grand Canyon, safe operating procedures for handling wildlife and occupational risks associated with disease transmission have concurrently been developed to protect wildlife biologists. All wildlife staff at Grand Canyon now carry cards developed by the CDC that inform medical staff that our biologists work with wildlife and may have been exposed to zoonotic diseases not commonly seen. Additionally, NPS veterinarians are consulted before any necropsies on carnivores known to carry plague are conducted. Taking actions to ensure that a tragedy such as Eric's death never happens again is a way that all biologists and all NPS employees can honor this great man.

In Memoriam

Eric will be remembered as a biologist's biologist, and his expertise went far beyond that of his intimate knowledge of the lions and other species he tracked at Grand Canyon and elsewhere. During his career, Eric captured and tagged 23 different species of carnivores. He worked in many areas of the United States and the world, including Chile, Nepal and Pakistan, where he researched the elusive snow leopard.

Eric, while working in Pakistan.
Eric working in Pakistan

In her comments made at the celebration of his life held on the canyon's South Rim on November 15, 2007, Elaine Leslie, Eric's former supervisor, said, "Eric was much like the lions he stalked. To catch a glimpse of the elusive Eric, you needed to be up at dawn as he hurried in and out of the office to gather up his freshly charged radio, dart pistol and other tools of the trade. By sunrise you could find him on the carcass of a freshly killed deer or elk, carefully reading the signs and placing a snare. Then off he would run, yes run, to check his traplines." She also said, "If you couldn't be Eric York, you at the very least wanted to hang out with him in the field and absorb every ounce of skill the man had to offer."

Those who learned from Eric — NPS wildlife biologists, interpreters and educators, researchers in Chile, Nepal and Pakistan, and his family and friends — will remember Eric by continuing his research and by continuing to share his passion for big cats, wildlife and wild places.


Eric's Headstone in MA

Eric York was a native of Shelburne, Massachusetts. He earned a bachelor of science in wildlife management from the University of Maine and a master of science in wildlife conservation from the University of Massachusetts.


Donations can be made in Eric’s name to:

(1) Grand Canyon Association, Attn: Susan Schroeder, P.O. Box 399, Grand Canyon, AZ 86023,

(2) Felidae Conservation Fund, 14 Cove Road, Belvedere, CA 94920,

(3) The Wildlands Fund, Division of Massachusetts Fish and Wildlife, Attn: Julie, 1 Rabbit Hill Road, Westboro, MA 01581.

Grand Canyon Nature Notes cover - Summer 2008

Grand Canyon Mountain Lion Program Archive

Mountain Lion Research (2009)
Mountain Lion Kittens Tagged (2007)
Discovering Mountain Lion Kittens - Trip Report (2007)
Remembering Eric York, Biologist
Lions and Loss
Mountain Lion Tracking (2009)

Download these articles as they appeared in the Summer 2008 Nature Notes (576kb PDF File)

Learn about Celebrate Wildlife Day at Grand Canyon National Park

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Last updated: August 9, 2021

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