Give a Hoot for Yosemite’s Great Gray Owl

A great gray owl and fledgling in a forest in Yosemite (Photo by Joe Medley)
This year’s theme for National Wildlife Week, “Branching Out for Wildlife,” celebrates trees and their importance to wildlife and people. In California, we couldn’t think of a more remarkable—or more rare—tree dweller to feature than Yosemite’s great gray owls.

Why should you give a hoot for Yosemite’s great gray owls? Joe Medley, a UC Davis PhD candidate and researcher affiliated with the USFS has studied the bird for years and even developed a method for using voice recognition software to track the owl that made my Top Ten California Wildlife Moments of 2012. “This is an amazing bird,” said Medley.  “They have a very specialized sensory system and can detect and catch prey under a foot of snow from sound alone.”

A close up of the distinctive great gray owl (Photo by Joe Medley)
Life with the great gray owl involves days and nights wandering in the mid-elevation forests and meadows of Yosemite searching and listening for owl sign. As one part of the project, Medley has been collecting molted feathers for multiple years and the research team will attempt to identify individual owls by using DNA testing. “If the technique works, we can determine how many owls use the habitat and other data that will enable us to estimate how healthy the population is.”

Medley works with John Keane of the USFS, and Josh Hull, of UC Davis, to study the health of the 100-200 great gray owls living in and around Yosemite. With blood samples from the research, Hull conducted genetic analysis and authored the paper that suggested the owl be recognized as its own subspecies in 2010. Author and birder David Lucas in his book, Sierra Nevada Birds, noted the decision: “One of the Sierra Nevada’s most majestic birds was awarded special recognition in 2010 when the population centered around Yosemite National Park was documented as a distinct subspecies (“California” Great Gray Owl, S.n. yosemitensis) found nowhere else on earth.”

Early biologists who visited Yosemite also noticed the uniqueness of the bird, including Joseph Grinnell and Tracy Storer in their 1924 book, Animal Life in the Yosemite: “The discovery of the Great Gray Owl in the Yosemite section was one of the notable events in our field experience. And what was most surprising was the fact that the bird was apparently quite at home, and nesting. No previous record of the breeding of this northern species of owl south of Canada is known to us, and its occurrence even as a winter visitant within the northernmost of the United States is not frequent.”

Yosemite’s great gray owl population was recognized as a distinctive subspecies in 2010. (photo by Joe Medley)
Yosemite’s great gray owls are rare—and part of a species overall that is listed as endangered in California. The park provides a last haven for great gray owls and is home to the majority of the entire state’s population. Research that Medley and others are conducting is vital to understand the long-term health of a population that has been evolutionarily distinct since the late Pleistocene.

But what makes the owls even more important to Medley is a personal connection. “They are that much more special to me because the first one I saw was with my dad.” Medley’s father, an avid birder and leader of a nonprofit in Yosemite for over twenty years, passed away in 2006.  “I am obsessed with raptors in general and for me this is the ultimate raptor. They are the largest of the North American owls. They live in the coolest place in California. They manage to survive winters in Yosemite. They can hear a mouse under snow.  For all these reasons, it gets my vote for most awesome bird.”