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Survey Efforts and Results
in Yolo County and the Middle Central Valley Region
The Burrowing Owl Preservation Society and Ian Taylor from Yolo Audubon Society recruited and coordinated volunteers who visited 10 blocks throughout Yolo County and one additional block in Sutter County. Surveyors contributed a total of 242 volunteer hours surveying for Burrowing Owls. Yolo County is a member of the Middle Central Valley Burrowing Owl Survey Region. The map below shows the extent of the 5 km by 5 km survey grid in the Middle Central Valley Region.  Our results from the 1990’s statewide survey estimated 595 breeding pairs in the Middle Central Valley. This accounts for 6% of the total estimated number of breeding pairs statewide during early 1990’s survey. The current survey aims to provide information that will enable us to assess any changes in the breeding population of Burrowing Owls both in the Middle Central Valley and across the state. Our goal for the 2006 field season was to visit half of the blocks known to historically contain at least one breeding pair in the Middle Central Valley Region as well as half of the randomly selected blocks to be sampled over the two year survey period (the other half will be visited in 2007). Survey goals in Yolo County were amply met. Surveyors visited a total of 11 blocks including 8 historically known breeding owl blocks and 3 random blocks. Disappointingly, breeding pairs were detected at only four blocks, all of which were owl blocks. Cursory examination shows that of the four historic breeding blocks that no longer harbor owls two have been vacant since the 1980’s, one block had owls present during the early 1990’s survey, and one breeding pair was present on the remaining block as recently as this decade.
Among the four blocks where breeding pairs were observed in Yolo County a total of 12 pairs were detected. Good news to report is that a persisting breeding population was observed on one block that harbored owls in the 1980’s. Two blocks were tied for the highest number of breeding pairs (four), one of which was the 1980’s block. Of the two other owl blocks where breeding was observed, one has a history dating back to the early 1990’s survey, and breeding was first documented on the other in 2003. At least 8 more owls blocks are scheduled to be visited in 2007, we’re looking forward to doing complete and thorough analysis for each survey region as well as the entire state after the second year of field data have been collected.
We particularly need volunteers who are interested in surveying in Colusa and Sutter Counties.
Thanks again to all volunteers who participated from Burrowing Owl Preservation Society and Yolo Audubon Society, they include: Neil Clipperton, Kirsten Dahl, Priscilla Hawkins, Cole Hawkins, Ursula Heffernon, Carolyn Hinshaw, Sarah Pitzer,
Catherine Portman, and Ian Taylor.
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