Photo by: Joe Medley

  Studies shared at the Yosemite workshop brought forward the need for more research to better understand the complex ecology of the Great Gray Owl.  But threats that are already understood include human disturbance when owls are on the nest and livestock impacts that affect meadow habitat in prime owl hunting areas.

  One study showed that over 50% of the time when owls at one Yosemite Park meadow were disturbed by approaching humans, the birds did not return to the meadow to continue hunting.  The obvious impact of millions of recreational visitors annually visiting the region’s forests, especially around meadow areas, means that nesting owls may frequently be limited in their hunting efforts or even driven away from their nests by human disturbance – leaving young owls vulnerable.

   One other highly sensitive issue discussed at the Great Gray Owl workshop session was the unfortunate mortality that has occurred in owls captured by State Fish and Game researchers in recent years.  As part of a radio-telemetry study, owls were caught, assessed, radio-tagged, and released.  Sadly, a number of the owls died during handling or shortly thereafter, while others died from various other causes.  The high mortality of owls caused by that agency’s research has created concern by other researchers as well as CSERC biologists.  With so few Great Gray Owls left in California, any survey efforts that put the rare birds at risk seem both counter-productive and unacceptable.  In contrast to the mortality caused by the DFG study, one Canadian research effort had only one death in 1,700 owls captured over many years.

   Despite the owls’ large size, they actually are lightweights that can fall victim to predation by Great Horned Owls and various other forest predators.  CSERC believes they serve well as an icon representing both the delicate nature of our local mountain ecosystem and the need for land managers to bend over backwards to protect species threatened due to human actions.  We applaud plans to create more artificial nest cavities and to look for other ways to benefit these rare owls.

Brenda Whited, CSERC biologist, posees at the workshop with a mounted owl killed in a car collision.