California Burrowing Owls Are Facing Extinction….If We Do Not Act

Photo Courtesy Wikipedia
Photo Courtesy Wikipedia

By Catherine Portman and Pam Nieberg

The burrowing owl is in imminent danger of becoming extinct…unless we act now. Once widely distributed in California, the burrowing owl has declined significantly over large portions of its former range. The number of breeding burrowing owl pairs statewide declined 60% from the 1980’s to the early 90’s and continues to decline at roughly 8% per year.  The Institute for Bird Populations documented declines of 8% to 10% in state-wide censuses in the early 1990s and 2007 and extirpation in 12 counties.  In 2014, a Yolo County census revealed a 76% decline in the seven years since the 2007 state-wide census.

Most of California’s remaining burrowing owls are on private property.  In a 2006-2007 state wide census, the Institute for Bird Populations found 87% of burrowing owl breeding pairs were on private property. In 2014, a Yolo County census found 67% of owls were on private property.

What happens to owls on private property when it is developed?

Most people are not only surprised, but horrified to learn that the owls are evicted from their burrows! It is called “passive relocation”, a practice condoned by the California Department of Fish and Wildlife (CDFW) and a practice many consider inhumane.

When a piece of property is proposed for development, the proponent hires a biologist to conduct biological surveys of the property.  If burrowing owls are found on the property, the biologist submits an “exclusion” plan to CDFW. The exclusion plan consists of placing a one- way door on burrow openings, so that when the owl leaves the burrow to hunt, it cannot get back into its shelter. The one-way doors are placed, not only on occupied burrows, but on every burrow on the development site.  CDFW approves the eviction plan and the biologist proceeds to permanently close all available burrows, leaving no burrows available to the evicted burrowing owls.

Burrowing owls use burrows for nesting, roosting, protection from extreme weather, and to evade predators. Without burrows, owls likely die because they do not have a safe place to retreat. No burrow—no burrowing owl.  At the very least, eviction is inhumane.

CDFW has not developed a Conservation Plan for burrowing owls. Instead, there is the 2012 CDFW Staff Report on Burrowing Owl Mitigation which is the key guiding document consultants and field biologists use to determine if development projects have significant impacts to burrowing owls and what mitigation measures lead agencies need to implement to offset these impacts. The Mitigation Methods section of the Staff Report includes an avoidance method that CDFW calls “Burrow Exclusion and Closure.”

The Staff Report includes the following description of what happens to evicted owls. “Eviction of burrowing owls is a potentially significant impact under CEQA (California Environmental Quality Act)… The long-term demographic consequences of these techniques have not been thoroughly evaluated, and the fate of evicted or excluded burrowing owls has not been systematically studied. Because burrowing owls are dependent on burrows at all times of the year for survival and/or reproduction, evicting them from nesting, roosting, and satellite burrows may lead to indirect impacts or take. Temporary or permanent closure of burrows may result in significant loss of burrows and habitat for reproduction and other life history requirements. Depending on the proximity and availability of alternate habitat, loss of access to burrows will likely result in varying levels of increased stress on burrowing owls and could depress reproduction, increase predation, increase energetic costs, and introduce risks posed by having to find and compete for available burrows.” The word “take” is sterile, regulatory language for “death”.Yet, despite their own admission that eviction likely leads to inadvertent take, CDFW routinely approves eviction plans.

Burrowing Owl Preservation Society (BOPS) has been engaged in burrowing owl advocacy for 13 years, and we have heard from frustrated biologists working with burrowing owls who believe that, over all, the practice of eviction is contributing to the decline and possible ultimate loss of burrowing owls in California.

Multiple data sources over decades have consistently demonstrated the burrowing owl population continues to decline. It is our opinion that evictions, allowed by CDFW, have contributed to this decline.

The CDFW refuses to examine alternatives to eviction.  BOPS wants to put pressure on the CDFW to end eviction, as the default position,  which is contributing to the decline and ultimate extirpation of burrowing owls.


If you want to help end this inhumane practice, please write, email or phone Charlton Bonham, Director of CDFW at1416 9th Street, 12th Floor, Sacramento, CA
(916) 445-0411. Also, contact your state Assembly Member and state Senator.  If you’d like to participate in burrowing owl advocacy call or email Catherine Portman at 530-666-0882

Read what respected burrowing owl biologists say about the practice of exclusion or eviction.

Ginny Short, an experienced biologist in Coachella Valley, CA told us, “In my opinion, without that hard data you can’t say they (exclusions) work. Not for mitigation. Sure, they keep the bird(s) from being buried. They keep the birds off the site. So if that is the goal, they work. But is it helping to save them?  Conserve them?  I don’t believe so. I see them disappearing from sites all over, particularly where they are being excluded.  I won’t support this unscientific approach until the (wildlife) agencies do some hard work to figure out what does work and what does not.”

An experienced biologist in Irvine CA said, “The passive relocation (exclusion) doesn’t seem to work. There is very little data for post-relocation (owl) survival. Then there is absolutely no protocol for what to do as the biologist watches helplessly as the owl is increasingly frustrated trying to (re)enter it’s burrow, then displaced, then usually depredated or is never seen again.”

In their paper titled, Burrowing Owl Status in the Greater San Francisco Bay Area (published in the Proceedings of the California Burrowing Owl Symposium 2003), Susan Townsend and Colleen Lenihan wrote: “Current protocols for managing burrowing owls in developing areas may also threaten their survival and reproduction. Eviction methods (i.e., passive and active relocation methods; CDFG 1995) used to remove owls from projects sites prior to development likely causes stress to these burrowing owls. When using one-way doors for passive relocation CDFG recommends that replacement burrows are available on nearby or adjacent lands secured as long-term burrowing owl habitat; however, in practice, replacement burrows are usually not provided. “ “Furthermore, in our experience, post-eviction monitoring (e.g., banding and/or telemetry) to determine the fate of these owls is rarely implemented or required.” “Displaced birds, unfamiliar with new areas, are less likely to breed (Peltz 2005) and are more susceptible to mortality from predators (Dyer 1987) .


About The Author

Disclaimer: the views expressed by guest writers are strictly those of the author and may not reflect the views of the Vanguard, its editor, or its editorial board.

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27 thoughts on “California Burrowing Owls Are Facing Extinction….If We Do Not Act”

  1. Tia Will

    Eviction methods (i.e., passive and active relocation methods; CDFG 1995) used to remove owls from projects sites prior to development likely causes stress to these burrowing owls”

    Reading this line with a mouth full of coffee nearly led to a coffee-computer collision this morning. My mind caught the word “likely” and I thought about how “likely” it would be to cause me stress if I arrived home, found that all the locks to my house had been changed and an eviction sign hung on my door !


  2. hpierce

    We have to realize that farming is the greatest threat to the burrowing owl population… burrows are destroyed every time a field is cultivated, and farmers do a lot to eradicate ground squirrels from their fields… the very critters that create the burrows that the owls then appropriate for their own use.

    Raptors also take a toll on ground squirrels.

    Burrowing owls don’t create burrows.

    The only reason burrowing owls got established in Mace Ranch was due to the cessation of farming on the Bruce Mace property where it was left fallow for years prior to development.

    Guess one could consider the ground squirrels as “developers” of the burrows. See what happens when you kill off or exclude developers?

  3. Tia Will

    See what happens when you kill off or exclude developers?”

    Cute. However, one question.

    Have you seen any dead or even destitute or homeless developers around ?

    1. hpierce

      Great… ignore four points (factual) and focus on the early morning satiric one.

      Oh, and yes… attended a funeral for a “developer” not so long ago.  How many destitute or homeless ground squirrels have you seen lately?

      Now, can we focus on the four factual points?

      1. Tia Will


        I am happy to address the factual points. But please do not pretend that you do not ever cherry pick from my points to address just one that you feel like answering. I am at a total loss as to why I cannot have a little light hearted fun with you since I am quite sure that you could not have felt that mine was a serious comment. But, I also am old enough to remember Joe Friday and certainly can play it as “Nothing but the facts, ma’am” if that is really where you want to go.

    1. hpierce

      Don’t cry, yet… the species are highly adaptive… the authors are not apparently biologists.

      Maybe 20 years ago, a property owner, seeking to improve/develop his property, got a bunch of cheap dirt from UCD (who he had previously been employed by)… he used it to get his property above the Base Flood Elevation.  It was in the County, but adjacent to the City.  He added ~ 2 feet of fill, over a known squirrel/owl site, entombing any critters.

      The outrage came to the CC… who had to say that it was not within their jurisdiction… the owner had not gotten a permit for the grading/fill from Yolo County… between the political outrage, and processes, it took ~ 2 years for the County to issue a mandate to remove the fill… putting the owner between the proverbial rock and hard place… to remove the fill, he would have to destroy a re-established habitat for both the squirrels and burrowing owls.  Sorry about the critters (truly) but had a great ‘belly-laugh’ as to the irony.

      Yet, any time ‘natural’ land in the valley is converted to farming OR development, the ground squirrels and owls are displaced.  Yet, within Davis, areas in Wildhorse and Mace Ranch were set aside as habitat for both… worked well for awhile, both not sure either are still viable, and do not pretend to know why.  Am not a biologist, by profession, but do understand eco-systems in general.

      The article seems less focused on biological issues, rather than ‘no development anywhere’.  If we banned all farming in Yolo County, would expect a big bounce-back of burrowing owls (and ground squirrels who create the burrows).  Perhaps that is a choice we should consider.

      1. Ron

        Yet, any time ‘natural’ land in the valley is converted to farming OR development, the ground squirrels and owls are displaced.

        True – there’s not a lot of “natural” (unimpacted) areas remaining.  (Our impact is far greater than our actual development footprints.)

        I still would find it sad to see owls desperately trying to get back into their home (without an ability to create a new one for themselves, as you’ve noted). Blocking owls from re-entry is not a “job” that I’d like to do, at least.

        I really doubt that we’re in danger of “no development anywhere”.


        1. Ron

          “Well, unless Marina and others get their way . . .”

          Just wondering (honest question):  Is there ever “enough” development in your view?  Should we just keep building/developing, as long as there may be “demand” for it?  No limits?

          I realize that development and population are intimately related. At some point, I hope that the population stabilizes.

          40 million currently in California.  Less than 1 million, before the gold rush (I think).  (About 3 lifetimes ago.)

        2. Frankly

          Ron – Do you get out much?  Travel around the state?

          I think you must not.

          I do… and most of the state is undeveloped and sparsely populated… plenty of space for all those cute little raptors to make a hole to live in.

        3. Ron

          Frankly:  “Ron – Do you get out much?  Travel around the state?”

          I do (and beyond the state, although not as much these days).  Please see my earlier point, regarding impact beyond actual urban footprints.

          Also, last time I checked, there were about the same number of roads, water sources, etc. these days, despite a doubling (or more?) of the population.  (Not including roads built only to serve developments.)

          How about you – is the “sky the limit” in terms of development/population?   Do you think that’s a desirable goal?  Good planning?

          Minor point – burrowing owls apparently don’t “burrow” on their own (as noted in the article/comments). They use holes made by other animals.

  4. Misanthrop

    They used to be out by Wildhorse Golf Course but then the town went crazy about killing coyotes and now the owls are gone from there.

    I think the loss of the owls is a serious issue. I think we could do a better job of preserving them. Its not like this hasn’t been known about for at least the last decade with owl loss discussed  at Mace Ranch Park and UCD. The city council should be trying harder to preserve these birds. So should UCD. I think I recently read that UCD is now the number 1 ranked school for environmental sciences yet they can’t protect these owls on their own campus. Shameful.

    1. Marina Kalugin

      wow Missy, more things we agree on …   🙂   hang around enough and that seems to be happening more and more……

      the owls are certainly needed and each time a habitat is lost, the spirits cry and the balance of nature on this planet is adversely affected…..

  5. Marina Kalugin

    many a burrowing owl habitat (and quite a few burrowing owls) were lost in the Mace Ranch development….

    yes, adaptive doesn’t mean that it is okay that some were blatantly plowed under in the name of development in this little ole town……

    of course, none of us would have a place to live if some of this hadn’t gone on…but we would be very wise to use traditional native american methods to choose where to build going forward.

    for some decades around this town one could hear the developers chomping at the bit….

    “wow that land is cheap because it is not in the city limits”  and  ” wonder what we could do with it to then make the CC approve and for us to make money”….

    ” push, push, push the development forward fast ahead without any regard for the need, or what should be protected still on the property”….

    of course, that has been my view from my vantage point over these many decades…

    My view:   if it cannot be done in a manner to happily co-exist, then perhaps it shouldn’t be built??????



    1. hpierce

      Marina… read my lips… the owls were not present in Mace Ranch until the Mace family stopped farming it (burrowing owls nor squirrels do well in tomato or safflower fields), and sold it to developers.  Only when the land was no longer farmed.  I don’t care where you currently live, or plan to move to (unless it is on solid rock)… unless you just live in a tent, your “space” was at a cost to possible burrowing owl habitat.

      Even then…

      1. Marina Kalugin

        and, hp, do you think I don’t know that?????and that is why they were also at the Wildhorse…

        LOL…and they would have been at Ricci, if we hadn’t lost that battle…but at least we won that war….sighhh….


        1. hpierce

          Not if the Ricci’s had continued to farm the land… yet, the land you lived on near the Ricci property, was even better suited to burrowing owls and their ground squirrel developers… you really don’t understand, do you?

          In fact, once the Ricci property was surrounded by your property and Willowbank, the Ricci property became unsuitable/unsustainable for burrowing owls… get a clue as to eco-systems…

  6. Edison

    About 12 years ago I had an interesting conversation with a CDFW biologist who specialized in western burrowing owls. He said that interestingly enough, airports are one of the best things that have ever happened to urban burrowing owls.  Airfields have wide expanses of short grass that makes excellent foraging habitat, lighted areas that attract insects at night, and lots of culverts beneath taxiways and runways that make excellent nest sites. During my 13 years of working at 4 airports in the Central Valley it was evident that burrowing owls indeed are attracted to airports. They seemed to adapt quite well to moving aircraft and vehicles and did not seem particularly bothered by people. And, there’s never been a documented incident of a burrowing owl causing a hazard to aircraft–unlike ducks, geese, ibis and other large birds.

  7. Napoleon Pig IV

    In general, I’d say the world contains way too many primates and not enough owls.

    But, it’s a Schroedinger’s cat kind of thing. The primates I’ve never met are disgusting burdens on the planet, but once I’ve met one, that individual primate becomes a valued and named entity. So, the same primate can be disgustingly worthless or prized beyond measure solely on the basis of a chance meeting with good ole Napoleon. What a paradox.

    For now, I vote for more owls. Oink!

  8. Roberta Millstein

    “the species are highly adaptive”

    “plenty of space for all those cute little raptors to make a hole to live in.”

    One things missing from the all of the above discussion (including the original article) is the fact that burrowing owls have been designated as a “species of special concern” in California:

    California Bird Species of Special Concern are defined as those species, subspecies, or distinct populations of native birds that currently satisfy one or more of the following (not necessarily mutually exclusive) criteria:

    are extirpated from the state totally or in their primary seasonal or breeding role and were never listed as state threatened or endangered.
    are listed as federally, but not state, threatened or endangered.
    meet the state definition of threatened or endangered but have not formally been listed.
    are experiencing, or formerly experienced, serious (noncyclical) population declines or range retractions (not reversed) that, if continued or resumed, could qualify them for state threatened or endangered status.
    have naturally small populations exhibiting high susceptibility to risk from any factor(s) that if realized could lead to declines that would qualify them for state threatened or endangered status.

    They need our help.

  9. Marina Kalugin

    what about the Swainson’s hawk s and the elderberry beetles on the Ricci property….

    so we got that nice little park down mace blvd as “alternative habitat”…

    but the Swainson’s hawks still come around Putah creek and that was such a struggle to even save that space…on the edge of the creek…

    …the Sac developer wanted to build over 220 houses on that 26 acres…what is there now, after a decade of work amongst many of the city folks, is better granted, but for many of us it was not what we bought when the general plan assured us it would be farm/open space ad infihitum…until there were enough new bodies on the city council who overturned the wishes of the former council…

    The super majority for Yes on A, cannot be allowed to ditz with this general plan until we get someone of Matt’s analytical skills on board……  (yes, I know he also was for A,   but he just didn’t have enough time yet to review all of the data)…..

    or, you can’t win them all, but you can certainly choose more wisely…



  10. Edison

    Kalugin:  having planned and implemented several Swainson’s hawk (SWHA) foraging habitat mitigation projects on land owned by Central Valley airports, I am amazed that development projects in Davis were allowed to mitigate the loss of hawk foraging habitat with parks.  That is completely contrary to State guidelines for SWHA habitat mitigation. There are published rankings for SWHA foraging habitat suitability. The most ideal type is alfalfa because it is typically harvested about six times during the SWHA active period (May 1 – October 1).  Each harvest exposes the rodents (mice, voles) and insects upon which SWHA prey.  I’m astounded that the City allowed a park to be used for foraging habitat mitigation. Perhaps the City did not have staff with biology backgrounds at that time.

    If memory serves, the EIR for the recently canceled Mace Ranch Innovation Center (MRIC) had proposed vineyards to compensate for the loss SWHA foraging habitat, which is completely unacceptable.  In fact, vineyards are regarding as being among the most inappropriate type of mitigation for the loss of SWHA habitat. Loss of SWHA foraging habitat will need to be carefully monitored in any future proposals to annex land to Davis for development.

  11. Matt Williams

    Edison said . . . “If memory serves, the EIR for the recently canceled Mace Ranch Innovation Center (MRIC) had proposed vineyards to compensate for the loss SWHA foraging habitat, which is completely unacceptable.  In fact, vineyards are regarding as being among the most inappropriate type of mitigation for the loss of SWHA habitat. Loss of SWHA foraging habitat will need to be carefully monitored in any future proposals to annex land to Davis for development.”

    Edison, my memory is no doubt equally faulty, but as closely as I followed the MRIC process, including attending all the OSHC meetings and FBC meetings, I do not remember any metion of vineyards to compensate for theloss of SWHA foraging habitat.  Since the MRIC plans for mitigation never got reduced to paper all we have is verbal communication.

    I have to wonder if what you heard wasn’t in the category of “whispering down the lane.”

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