Failed Burrowing Owl Mitigation


BurrowingOwlBy Catherine Portman and Pam Nieberg

Guest Comentary – As many local environmentalists recall, nesting burrowing owls at Mace Ranch were illegally disked into the ground in 2000. As part of the mitigation for this loss, the City of Davis, as the lead agency for the Mace Ranch development project, worked with Yolo County to create a Burrowing Owl Reserve at Yolo County Grassland Park on Mace Blvd. south of Davis.

The Mitigation Agreement (“Agreement for the Management of Burrowing Owl Habitat at the Grasslands Regional County Park” 2004) included a Management Plan (“Yolo County Grasslands Park Burrowing Owl Habitat Management Plan”, Albion Environmental, Inc. September 2004) for the Reserve. The Management Plan requires the vegetation on the Reserve be kept short, as burrowing owls require short vegetation to avoid predators and see their prey in order to survive.

The Management Plan unambiguously defines the vegetation height objective: “Maintain herbaceous vegetation height and density in a range suitable for year-round occupancy, including nesting and foraging by burrowing owls.”

The Management Plan specifically defines the height of vegetation burrowing owls need to survive:  “Effective Height of the vegetation in the Reserve Area will be no greater than five (5) inches in the first half of April of each year and no greater than four (4) inches after the growing season when herbaceous vegetation has senesced.”  The Management Plan requires bi-yearly (April and July) vegetation height measurements and burrowing owl census.

The City of Davis’ Wildlife Resource Specialist conducted the vegetation height measurements and owl census between 2005 and 2007. From 2007 to 2009 the City engaged a certified burrowing owl biologist consultant from Sustain Environmental, Inc. (SEI) to conduct the required surveys.

Unfortunately, a review of these vegetation height measurements demonstrates that the City has completely failed to meet the specified height requirements and has not been in compliance with the Management Plan since 2005. The height has been above 5 inches at every April measurement with highs of 12 and 20 inches. One single July measurement was below 3 inches when the park was grazed. All the other July measurements were above 4 inches with a high of 10 inches.

SEI’s 2009 report summarized the City’s non-compliance with the vegetation height requirement: “The survey data suggest that the current mowing/grazing regimen is not providing the desired results and/or that the compliance standards and goals may not be well understood. The standard is not merely to reduce vegetation height in advance of scheduled bi-yearly inspections, but to manage the vegetation year round.”

In their 2008 report SEI wrote, “…vegetation heights of four times the standard (16 and 18 inches) were measured along some of the transects, and the mean effective height of every one of the transects exceeded the compliance standard by at least 25%…From a burrowing owl’s perspective, approximately half of the reserve was unsuitable habitat at the time of the July survey.

The Management Plan requires a bi-annual burrowing owl census to determine the effectiveness of the Management Plan in actually maintaining or increasing the number of burrowing owls at the site. In 2005 a single owl was sighted in February and March. In 2011 a single owl was sighted in April. The last known breeding of burrowing owls at Grasslands Park in 2005 was on the radio-controlled airplane runway where the grass is routinely mowed.

Burrowing Owl Preservation Society and the Sierra Club Yolano Group have written letters and held meetings with the City’s Wildlife Resource Specialist, the Sustainability Program Manager and the current Mayor asking the City to fulfill its legal obligations and actively implement the Management Plan, but to no avail.  Burrowing Owl Preservation Society has also requested a meeting with the Davis City Manager, but received no response.

This lack of action on the part of the City to meet its environmental obligations is  disconcerting. It is unconscionable that a City that prides itself on its environmental reputation and its respect for wildlife is disregarding a legally binding agreement to properly maintain the burrowing owl habitat at Grasslands Park. It is time for the City to step up and fulfill the terms of the contract to which it agreed.

Catherine Portman is on the Burrowing Owl Preservation Society, Co-founder and CEO.  Pam Nieberg represents the Sierra Club Yolano Group, Secretary.


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3 thoughts on “Failed Burrowing Owl Mitigation”

  1. Michael Harrington

    The CC had a special meeting out at the Mace 9 acres. Brenda johnson and Frazier Shilling and Shawn Smallwood did a fabulous job showing the CC why 9 acres was minimum. However, I lost that vote 4-1.

    Of course 4 acres was too small.

    Of course the owls died or fled.

    How sad, and predictable.

    Thank you, Pam, for writing their obituary so we can remember them.

  2. roger bockrath

    Catherine and Pam,
    Just when I begin to think I know what’s going on some body comes along and wakes me up. I have been associated with the Yolo Bowmen who planted and maintain the archery range forest on Grasslands Park property. For several years I have been aware that sheep graze on the grassy part of the park. They have been poorly cared for (I remember several deaths due to failure of the cocky to provide water) and have wandered onto the range done damage to our facilitys.

    It had never occurred to me that the reason for their presence was for habitat modification for burrowing owls. I have spent many hours on the Bowman Range and have never seen a burrowing owl. Lots of other kinds of owls in the wooded portion of the park, and lots of turkeys, but alas no burrowing owls.

    I wonder if the Bowmen could be of assistance in keeping the grass mowed in the “safety areas” that surround our forested shooting lanes in order to create habitat for the owls. We do a lot of mowing any way to reduce fire hazards at the range. If this could help solve the habitat problem, and bring the city into conformity with their legal obligations, we may be able to provide some assistance.

    It has been my experience, over the thirty years I have resided in Davis, that the city’s commitment to the environment is little more than lip service and a never ending series of self administered awards for environmental stewardship, with very little evidence to back up the claim. If I or the Bowmen can be of assistance please feel free to contact me or the Yolo Bowmen. I think that you will find that people who hunt are on the front lines when it comes to environmental stewardship.

    Thank you for a very informative piece!

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