By Jack Dumbacher

The Barred Owl (Strix varia) is the eastern cousin to our western Spotted Owl (Strix occidentalis).  Like the Spotted Owl, the Barred Owl lives in forests, hunts at night, and feeds largely on small mammals.  They differ in that the Barred Owl is more of a generalist opportunistic predator (feeding also on crayfish, snakes, even small birds and insects), has a broader habitat tolerance, and is slightly larger and more aggressive than the Spotted Owl.

In the last 100 years, Barred Owls have gradually extended their range westward, and around 1959, they began to formally “invade” the Spotted Owl’s range in British Columbia.  By the 1970’s, Barred Owls were documented in Washington and Oregon, by 1976 they were documented in northern California, and the first Barred Owls were documented in Marin County in 2003.

On the one hand, this is now one more good bird that you can reliably “tick” on your Bay Area bird list.  On the other hand, evidence is mounting that Barred Owls are having a significant detrimental effect on Spotted Owls – they compete for food and nesting sites, they are aggressive to Spotted Owls, they breed faster and disperse farther, they even interbreed with Spotted Owls and have an unknown effect on each others genomes.

Barred Owl (left) and Spotted Owl (right) / Photo courtesy of CNN

In 2011, the Revised Recovery Plan for the Northern Spotted Owl identified competition with the invading Barred Owl as one of the most pressing threats to the Northern Spotted Owl.  The easier it is to see a Barred Owl, the harder it is to see a Spotted Owl.

Again, on the one hand, this is a fascinating biological experiment.  What will be the final outcome?  Will the owls interbreed to become a new hybrid species?  Will Barred Owls outcompete Spotted Owls in the western states?  Or will they achieve an equilibrium and continue to co-exist side by side?  No one knows the answer, but one goal of conservation biology is to create a natural environment where species can continue to evolve and do naturally what species will do.

Spotted Owl / Photo by Jack Dumbacher

On the other hand, it is not clear that this experiment is completely natural.  There is some hint that human-caused habitat and climate change aided the Barred Owls in their westward dispersal. Human changes to western forests may have tipped the hand of evolution to favor Barred Owls in these now-disturbed forests. …

Golden Gate Bird Alliance encourages San Francisco voters to approve Measure B, the $196 million parks bond that will be on the November ballot.

We reviewed arguments both for and against the Parks Bond. Some of our allies make strong cases for opposing the bond, based on the S.F. Recreation and Parks Department’s poor track record on issues important to local wildlife.

However, on balance we feel that the bond provides much-needed funding for city parks and for wildlife habitat — including $6.5 million for natural areas in Golden Gate Park, $2 million for Lake Merced, $4 million for trails, and $35 million for waterfront parks at the Port of San Francisco.

San Francisco’s parks badly need improvement and maintenance. If this measure fails, there won’t be another opportunity to fund parks for a number of years. So we are supporting the bond measure — and then we will keep a close eye on how Rec & Parks spends the money, to make sure that wildlife and habitat get their fair share.

You can read the text of Measure B here, or view arguments for and against it in the ballot pamphlet here.

Other Ballot Measures

As a 501c3 nonprofit organization, Golden Gate Bird Alliance can not endorse political candidates. As a local Audubon chapter, we do most of our advocacy on Bay Area issues. So when election time comes around, our focus is on local issues and ballot measures.

In addition to the San Francisco parks bond, our Conservation Committees and Board of Directors reviewed two other local ballot measures. We decided to take a neutral position on both of them:

Oakland Zoo Parcel Tax: Oakland voters are considering Measure A1, a parcel tax that will generate $6 million per year for 20 years. While critics say the zoo is expanding too aggressively into Knowland Park, which contains sensitive habitat, zoo officials say the parcel tax money will not be used for that expansion and will improve animal care and nature education. GGBA takes a neutral position.

You can read the text of Measure A1 and pro and con arguments here.

Berkeley Measure T: Berkeley voters are being asked to provide $30 million for improvements in West Berkeley and adjust the zoning to allow for more development. We opted to stay neutral because the activities that would directly affect Aquatic Park, a local important bird area, have been tabled for decision in early 2013.…

By Ilana DeBare

“When it’s a jar,” was the answer to that old joke.

But we have a new answer – when it’s a mural!

Over the past few weeks, Berkeley artist STEFEN has been busy creating a Bay Area Birds mural on the (formerly beige, formerly boring) door to the Golden Gate Bird Alliance office on San Pablo Avenue.

The mural features seven endangered species that have been the focus of Golden Gate Bird Alliance conservation campaigns.

As the project got underway, we were so excited that we decided to document STEFEN’s process and share it with you. So here’s a step-by-step view of the transformation:

The door before Starting the landscape -- looking west across the Bay from the Albany Mud Flats STEFEN adds the Golden Gate Bridge The water and distant shores take shape GGBA Executive Director Mark Welther and STEFEN in mid-mural The Albany bulb, more vegetation and some.... birds! STEFEN leaves space for the birds - can you tell what they will be? Yep, this one is a Clapper Rail

One of those we included is the California Clapper Rail, which shelters in the native marsh plans that our volunteers and Eco-Education students have planted at Martin Luther King Jr. Shoreline Park in Oakland.

Stefen adds a Golden Eagle

We also included a Golden Eagle, one of the species that have been killed in large numbers by wind turbines at the Altamont Pass. Thanks to GGBA advocacy and legal action, the wind companies are starting to replace those turbines with new ones that are less dangerous to birds.

The finished door! But wait... what's that in the upper lefthand corner?

STEFEN painted the same birds from the mural in flight, on pieces of wood that he attached to the hallway wall. So there is now a trail of birds leading down the hall to our office. Cleverly, the wood images can be detached when it is time to repaint the hall.

Line of birds leading to our office Can you identify this li'l fella? And this one? And this not-so-little one?

Pretty cool, huh? If you’re in the neighborhood, come by our office at 2530 San Pablo Avenue (at Blake) to see it yourself! Our office hours are 1 to 5 pm on weekdays.

Or come by on Friday October 19 for our Open House and calendar launch party. From 1 to 5 pm, we’ll be celebrating the talented Bay Area wildlife photographers who donated their work for our beautiful 2013 Birds of the SF Bay Area wall calendar.…

By Rusty Scalf
The birds seem to come out of nowhere. Literally. The late afternoon sky is blue, with a few clouds, a few gulls, a couple of Ravens. Then I notice two tiny bat-like creatures well above the old smoke stacks.
Bat-like but not bats. Swifts. Tiny, gray, fast, erratic.
Then a group of five heading the same way meet the two and coalesce like little droplets to seven, then disappear. And so it begins. Fifteen minutes later there are perhaps 300 in a gnat-like swarm. Ten minutes more it’s 600 that decide, for a short while, to emulate a lava lamp, a tight morphing blob of birds, only to scatter to gnat-like entropy once again.
The light becomes long, the sun is just above the hills to the west, and the swifts keep building. Eventually they’re a vortex, swirling around the complex a couple hundred feet up.  As the light begins to fade, the scene above the old smoke stacks is other-worldly. The thousands of birds now make estimation a dizzying prospect.
My goal is to estimate how many swifts are present. Impossible really. The best one can do is follow a set protocol and hope for consistency. The task: train a scope on the top of a stack, click-counter in hand, and click once for every ten (or some gestalt sense of ten) swifts that enter. Entry rate seems to peak at approximately ten birds per second into the favored north stack.
Swifts at McNear Brickyard / Photo by Kerry Wilcox
A joint Golden Gate/Ohlone Audubon outing on Sept. 22, 2012 recorded an estimated 19,500 birds!  Double the highest previous count! The number of birds at the stacks rises and falls, often dramatically, day by day.  Larry Schwitters, who tracks the West Coast migration of Vaux’s Swifts, estimates (based both on Chimney Swift banding data and his own census numbers) that typical residence time at a migratory roost is 3-4 days within a range of 1 to 7 days.  At McNear Brickyard here in San Rafael, September counts of 500 to 10,000 have been typical. More than 19,000 was just over-the-top. Lucky, eh? Every once in a while…..
Swifts at McNear Brickyard / Photo by Kerry Wilcox
Vaux’s Swift is the smallest North American swift species, about 4.75 inches long, and closely related to the eastern Chimney Swift. Both species evolved to nest in large hollow snags, which have almost entirely disappeared in the east and become ever more scarce in the west.…

By Phila Rogers

When I first opened this dense volume, I wondered: “Do I really need another bird book?”  It’s a rhetorical question, of course, because I seldom can resist, whether it’s yet another guide book or a personal account of  a birding  life.

David Lukas’ Bay Area Birds  (Lukas Guides, 2012) is jam-packed with information written to compliment your field guide. These days, I do as much reading about birds as going into the field to find them.  With winter residents beginning to show up, I want to know more about the birds I’m hearing and seeing.

For each of 221 species, Lukas devotes often several paragraphs to what he calls their “Life History” and a shorter account  to “Range.”

The only illustration is a map showing his definition of “The Bay Area Region.” He divides the coastal mountains into the outer and inner coast ranges, including the Berkeley-Oakland hills as part of the inner coast range.  In my experience, this is not where they belong.  Their location opposite the Golden Gate creates a climate and habitat similar to the damper ranges along the coast.

That aside, Lukas gives himself an impressive mantel of authority by acknowledging the help of such notables in the birding community as Bob Richmond (who read the manuscript) and Rich Stallcup who gave his “papal blessing” to the project.

He gives one of the fullest, most interesting, treatments to one of our drabbest and most common resident birds — the California Towhee.  I like that.  For instance:

“Their habit of feeding on the open ground, along with their accommodating acceptance of humans, means they are a conspicuous presence around countless backyards, suburban neighborhoods, and city parks…. Pairs are highly sedentary and mate for life.”

Bay Area Birds has many interesting tidbits of information — Gnatcatchers pair up within 24 hours of their arrival on territory; Bufflehead are small enough to nest in tree cavities made by Northern Flickers; adult Wild Turkeys are reported to eat one pound of food per meal.

However, Lukas does not give sources for his information, which means the reader is asked to take his word.  What I like about Cornell’s Birds of North America Online is they back up descriptions with citations giving the researcher’s name and date of their paper so you can dig deeper.

Before writing my review, I passed the book on to an expert birding friend who was trained as a scientist. …