Death of Great Gray Owl in Yosemite underscores plight of species
CSERC Newsletter
Photo J. Medley
This summer, a Yosemite Park report underscored how challenging it is for the rare great gray owl to survive with so many threats to the species.
The focus of the report was a female owl that was at least 8-years-old, since a research team had banded her as a mature adult in 2007. She was highly productive - nesting and raising young five times in the last seven years. As the report noted, this was impressive because great gray owls typically only nest when the level of small mammal prey is highly abundant. This female successfully incubated, defended, and raised nine juvenile owls, including two in the spring of 2012.
The success of this owl was especially notable because only very persistent females are successful at raising young. From hatching to fledging, juvenile owls need care for two months. The female spends one full month of that time almost entirely stationary, incubating the eggs high up in a broken top of a tree where she is fully exposed to rain, wind, or snow. The Yosemite report listed this female as the most productive female owl documented to date in the Park.
Sadly, the reason this report was publicized was because this impressive great gray owl was stuck and killed by a vehicle traveling on Highway 41 in the Park. Not only did her death leave behind her two juveniles that then became the total responsibility of her mate, but her loss was also a blow to the small population of owls struggling to survive in the local region. There may be only 150 to 200 great gray owls in all of California. Park Service and Forest Service scientists have documented more than a dozen great gray owls killed by vehicles just in the past 10 years. Vehicle mortality adds to other threats such as predation, severe weather events, degraded meadow habitat from livestock grazing, lack of prey, and disturbance by birders trying to get too close.
Posts
