Waiting for Owls

Ground squirrels are key to Burrowing Owl habitat; the birds roost in their burrows.

The area is mowed, the fennel is leveled, the decorative fence was repaired, the gates are closed, new docents are trained.  All looks ready for a visit from Burrowing Owls.  Even the ground squirrels seem to be waiting expectantly, as in this photo.  But will the owls come?  The last of these beloved creatures to settle in the protected area set aside for them on the northeast corner of the park was sighted in March of 2017, eighteen months ago.

One owl was killed in the park in late November of 2016, almost certainly by a dog.  No one saw any owls in Cesar Chavez Park during the winter of 2017-2018.  A zero-owl season has never happened before in the ten years since Audubon volunteers began watching this area.

The killing of an owl and the unprecedented total absence of owls the following year are red flags. But there was no sense of crisis in the docent training program Saturday September 22 in the Nature Center in Shorebird Park, on the Marina’s south side.  Proceeding as if there were nothing to be concerned about, docent trainer Della Dash lectured the dozen or so recruits, the majority of them first-timers, about filling in data sheets and inviting the public to view the owls.  Dash’s theory is that three owls came to check out Cesar Chavez Park in early October last year, but the fence gates across the paved walkways into the area were not closed yet, so the owls flew north to the Albany Plateau and settled there instead.  The hope is that this year these owls will return to check out the park again. This time they will see that the fence gates are up already, and so they will come back and settle here for the winter.  That’s the late gate theory.

Burrowing Owl in Cesar Chavez Park protected area 2/5/2014. My photo.

We’ll see within the next week or two whether this theory is correct.  The first owls last season were spotted on the Albany site on October 4 2017.  The earliest owls ever to arrive since records have been kept showed in Cesar Chavez on September 29, 2013.

If the owls don’t return to Cesar Chavez Park fairly soon, we’ll need to consider explanations other than the late gate theory for their absence.  Fortunately, there is data. Since the 2010-2011 winter season, Audubon volunteer docents have collected data at the site and reported it to Noreen Weeden, Audubon’s volunteer coordinator.  Weeden has compiled the data and published it in annual reports posted on a docents’ Yahoo email group.  I’ve posted copies below.  In addition to the number of owls seen, the data show the number of hours that volunteer docents were present on the site, and (among other things) the number of off-leash dogs that docents saw while present at the protected area.  From this, Weeden calculated the number of off-leash dogs per hour (DPH) per season at Cesar Chavez.  The raw data look like this:

The following chart shows these data visually.  The thin red line represents the number of off-leash dogs per hour that docents reported, left to right from 2010-2018.  The thin blue line is the number of owls that docents reported for the season.  The heavy lines are trend lines that condense and summarize the data over time; the spreadsheet program generates them automatically based on the data.  The red trend line shows a rise in the number of off-leash dogs over the 2010-2018 period.  The blue trend line shows a drop in the number of owls in the same time frame.  The two trend lines head in opposite directions.  As the number of off-leash dogs increased, the number of owls dropped.  During the 2017-2018 season, the number of off-leash dogs seen at the site rose to a record high.  The number of owls here in that season was zero, a record low.

Of course, correlation is not causation.  Still, when one of the elements in the correlation consists of conscious, intelligent, and vulnerable living beings, it’s fair to suppose that the growing peril of uncontrolled dogs formed at least part of the owls’ motivation for choosing to live elsewhere.  Although projecting human motives into the heads of animals is always hazardous, the off-leash dog hypothesis has both a data trend and a significant anecdote to support it, whereas the late gate theory is pure speculation.

In 2008, Weeden reports, a dog dug up an owl’s burrow and the owl flew off and didn’t return.  At that time, Audubon volunteers rose to action and installed a plastic construction fence, four feet high, around part of the northeast corner of the park.  That fence was orange; the same fence can be had from Home Depot and similar stores in green.  Apparently that fence worked; in 2010-2011, the area hosted five owls, still a record.  The flames of Audubon owl stewardship have cooled since then.  Neither Weeden nor Dash would entertain a proposal, made in this blog last year, to repeat the 2008 fence construction.  In Dash’s view, expressed repeatedly at the docent training, the existing decorative fence, installed in 2011 as part of the Open Circle public art project, is perfectly adequate protection for the birds against dogs.  Dash believes that the Off-Leash Area is well marked, dog owners obey it, the fence is good, and thanks to public education, off-leash dogs are not a problem for owls in Cesar Chavez Park.

This belief is remote from the facts.  In reality, the Off-Leash Area has lost almost all of its boundary signs over the past few years, as I’ve documented in these pages.  Even where the boundary signs remain, many dog owners ignore them, as any observer in the park can testify.  The data that Weeden compiled from docent reports shows that the off-leash dog peril has not been declining but rather growing to record highs.  Far from being a dead issue, it’s a more urgent problem than ever.

Of course, the owls have minds of their own, and some of their behavior looks paradoxical in human eyes.  Researchers report that the owls like to nest in the rough near airplane runways, heedless of the noise.  They’ve been seen settling on soccer fields.  The biggest concentration of breeding Burrowing Owls in California is in the Imperial Valley, a man-made agribusiness region with laser-straight canals, complete with cropduster flyovers and monster combines.  In Cesar Chavez Park in the past, they’ve sometimes settled so close to a paved path that people could trip over them.  They could well decide to damn the trendlines, ignore the canines, and return by the dozen.  Let’s hope so.

Here for reference are the Annual Reports published by Noreen Weeden of the Golden Gate Audubon Society.  (Full disclosure: I am a member.)

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