Meaningful help for owls

By Eddie Bartley and Noreen Weeden

Ari Dalfen, an “almost” 9-year-old and a 3rd grader, hails from the Richmond District in San Francisco. Recently, along with his moms, Ari visited the California Raptor Center in Davis, CA. The facility is part of the U.C. Davis Veterinary Medicine which treats over 300 hawks and raptors each year for a wide variety of medical needs and also provides information to the public.  Ari has always been fascinated by hawks and owls so, after witnessing injured birds being rehabilitated at the Center, he became inspired to do something to help hawks or owls.

For his Jewish Studies class at Brandeis School of San Francisco Ari has been asked to develop a tzedakah project (tzedakah means “justice” in Hebrew) which serves the community and also something that is personally meaningful to him. Ari asked the good folks at California Raptor Center about volunteering but, on discovering he is not yet old enough to volunteer there, realized he had to think outside of the box, so to speak. The Center’s fine website describes how raptors play a critical role in our environment. Owls, particularly Barn Owls, provide significant ecosystem services keeping rodent numbers in check by consuming huge numbers of mice, voles and rats especially during the breeding season.

Perhaps this fellow is looking for a home? Photo by Bob Lewis

Reduction of vegetated habitat due to human development pressures in California has depressed wildlife numbers and biodiversity generally and this has had a negative impact on both diurnal (those active dawn and dusk) and nocturnal (those active mostly at night) raptors. A more recent double-whammy to eagles, falcons, hawks, owls and other predators is that powerful modern rodenticides used to poison rodents also causes secondary poisoning to any animal who selects that compromised rodent (an easy target) for prey. A third modern problem for cavity nesting birds, including many owl species and songbirds, is a general lack of natural nest cavities due in part to people’s proclivity to cut dead trees that may otherwise be used for nesting. For many animals the lack of an appropriate nesting cavity is a primary population limiting factor. Fortunately for Barn Owls, people have discovered that installing a specifically designed nest box in an area where rodenticides are not used and in appropriate habitat is a great way to provide a safe nesting place that may not exist otherwise.…

A winter day at the Salton Sea

By Holly Bern
The Salton Sea, in the Imperial Valley of southern California, is a critical stop for many birds on the Pacific Flyway, and I had been hearing about it for years from a number of birding friends.  The north end of the sea is about 7 – 8 hours away from the Bay Area, or more depending on traffic, so it takes a little planning and at least a few days to do it right.  When tour leaders Eddie Bartley and Noreen Weeden offered the trip through GGBA I jumped at the chance to experience the Salton Sea with folks who have been exploring the area for many years and know its birds, natural history and geology.
The trip from the Bay Area to the Salton Sea roughly follows the path of the San Andreas Fault as I-5 parallels the fault line down into the Los Angeles area.  When I think of the San Andreas Fault, I immediately think of earthquakes and San Francisco, I don’t think of southern California birds.  But, the San Andreas Fault provides a very literal connection from the Bay Area to this wonderful birding habitat. It is the movement of the plates at the borders of the San Andreas fault line that have crushed the alluvial deposits at  certain points within the greater Imperial and Coachella Valleys leaving an impervious layer that keeps under
California Fan Palm – Photo: Noreen Weeden
ground springs from reaching farther down.  Palms and other plants are able to tap into these areas, creating oases.  The Dos Palmas Preserve, along the northeastern side of the Salton Sea, where our trip officially began, is one such spot. It is home to the California fan palm, or Washingtonia filifera, the only palm native to the western US.  The fruits, seeds, and leaves of the palms provided many uses for Native Americans, and the oasis provides habitat for birds and other desert animals.  We were treated to southern desert specialties:  Black-tailed Gnatcatcher, Phainopepla, Verdin, Abert’s Towhee, and a surprise appearance of a couple of Sage Thrashers, which were new trip birds.       

                                                                                                                     

Black-tailed Gnatcatcher – Photo: Eddie Bartley
 
Salton Sea – Photo: Noreen Weeden
Salton Sea – Photo: Noreen Weeden
From Dos Palmas we headed to the North Shore Marina.  Eddie and Noreen indicated that the composition of the bird species has been changing and may be due to the increasing salinity of the sea and the subsequent alteration in fish species. …

Brown-headed Cowbirds in the Bay Area

Brown-headed Cowbirds in the Bay Area

Editor’s Note: When I was new to birding, I was puzzled by the hostility shown by many veteran birders to the Brown-headed Cowbird. Mere mention of a cowbird among sightings during the Christmas Bird Count compilation dinner would draw boos! This excerpt from San Francisco’s Natural History: From Sand Dunes to Streetcars, the new book by Harry Fuller, explains why. 
By Harry Fuller
One pernicious newcomer to the Bay Area avifauna is the Brown-headed Cowbird. Cowbirds are successful nest parasites. A female cowbird can lay dozens of eggs in a single summer, each in a nest built by another species. When the cowbird egg hatches, the chick pushes out the smaller nestlings of the host species and thrives with its co-opted parents. American Robins evolved alongside cowbirds, so robins can and do recognize and destroy cowbird eggs. Most western bird species do not have that ability, and are easily duped.
Brown-headed Cowbird by Eleanor Briccetti
The cowbird’s fledged offspring need forest patches and heavily grazed fields to feed in. Once followers of the large bison herds on the Great Plains, cowbirds quickly recognized the new source of plenty that arrived with settlers. The pioneers’ livestock left uneaten grain and the inevitable manure. That in turn attracted insects that fed the cowbirds. Elliott Coues described some cowbird flocks in the 1870s: “Every wagon-train passing over the prairies in summer is attended by flocks of the birds; every camp and stock-corral, permanent or temporary, is besieged by the busy birds, eager to glean subsistence from the wasted forage.” So, although originally confined to areas east of the Rockies, the cowbird has now overrun much of the North American continent.
Cowbirds on a bison at Vargas Plateau Regional Park in Fremont, by Jerry Ting
One cowbird was spotted east of Los Angeles in 1889. Then in 1895, Charles Bendire, a military man who took advantage of his various postings to bird intensively, reported seeing a few cowbirds in the Great Basin. By 1907, one was seen in Bakersfield; more were seen then in Fresno and Fremont in 1911 and 1912. In 1926, two eggs were found in a Common Yellowthroat’s nest at Lake Merced in San Francisco. By 1931 the cowbird had spread to Sacramento, and by 1934, to Berkeley, Oakland, and Yosemite National Park. By 1941, it had reached Eureka, and Tahoe by 1957. In 1969 Laurence Binford saw a Wrentit feeding a juvenile cowbird at Lake Merced.…

San Francisco’s changing bird life, Part 1

San Francisco’s changing bird life, Part 1

This is the first of three excerpts from San Francisco’s Natural History: From Sand Dunes to Street Cars, a new book by longtime Golden Gate Bird Alliance member and trip leader Harry Fuller.
By Harry Fuller
Nothing more clearly shows the vast changes in the bird life of San Francisco than the near extirpation of the California Quail since 1980. People have severely affected bird populations, mainly by hunting and by altering habitat, but in other ways, as well. In some cases, the change was just that humans stopped persecuting a species and it returned or thrived anew. For the most part, however, the alterations are in our use of guns, poisons, pavement, construction, landscaping, gardening, irrigation, and undergrounding of streams. The gradual warming of California’s climate is the broad background to habitat changes wrought by urbanization, agribusiness, and widespread irrigation.
All these activities continue to affect the natural world so that some species are favored over others. Some birds now found in San Francisco would not have been present before the Gold Rush. Others have vanished forever. There are on-going changes in the city, with one species appearing and spreading rapidly while another quietly vanishes.
Yellow Warbler is a species that has diminished in San Francisco. Photo by Michael Lee.
Bird species whose populations were eliminated or diminished in San Francisco include Warbling Vireos, Yellow Warblers, Pacific-slope Flycatchers that favor streamside forests. Among the birds common in pre–Gold Rush San Francisco but now greatly reduced or gone altogether are American and Least Bittern, California Quail, Scrub-Jay, Spotted Towhee, Bewick’s Wren, and Wrentit. It’s likely that Nuttall’s Woodpecker, Acorn Woodpecker, Oak Titmouse, and California Thrasher were living in suitable habitat in San Francisco before the onslaught of agriculture and urbanization. Early accounts of San Francisco mention grizzly and black bear, cougar, elk, deer, jack rabbits, coyote, wolves and skunks. Only the coyote and skunk can be found here today. Introduced tree squirrels and opossum also thrive in the city.
San Francisco’s Natural History, by Harry Fuller
In 1899 Charles Keeler found Pygmy Nuthatches only in mountains, not in the Presidio or Golden Gate Park, where now they can be seen regularly. The raven, said Keeler, was “found generally in places remote from civilization.” Roosting by the dozens in Golden Gate Park, ravens are now prominent among beach walkers on Ocean Beach. In daytime, you may find dozens of them patrolling the sand for anything a careless person may have lost or left on the sand.…

Applause for the Ridgway’s Rail

Applause for the Ridgway’s Rail

By Miya Lucas

Walking on the shoreline of the North or East Bay, you have a chance to encounter one of our year-round residents that is also an endangered species – the Ridgway’s Rail.

Formerly known as California Clapper Rails, Ridgway’s Rails are secretive birds and you’re likely to hear them before you see them. Their clapping sounds remind me of hands clapping, like an audience applauding after a Berkeley Rep theater show.  When I hear them, I picture Ridgway’s Rails applauding each other after making a quick guest appearance.

The first time I saw a Ridgway’s Rail was at Arrowhead Marsh at Martin Luther King Jr. Regional Shoreline in Oakland. It was a blistering cold winter day as well as a King Tide, an unusually high tide that drives the rails onto higher, more visible ground. There were lots of people there observing Soras and Ridgway’s Rails, along with what seemed like a million shorebirds roosting on the broken pier.

Ridgway’s Rail by Miya Lucas Birders at Arrowhead Marsh in Martin Luther King Jr. Regional Shoreline during a King Tide on January 1, 2018. Note the high water level. Photo by Rick Lewis.

One Ridgway’s Rail in particular caught my eye. it was walking and preening on a large log about 100 feet from the shore, and seemed oblivious to the fifty or more humans observing it.  I was captivated by the vivid orange colors on his breast and his bright shiny eyes, and then he opened up his wings and displayed another blast of color on the inner wings.  He sang for us with his clapping call. It was love at first sight.

The Ridgway’s Rail is a very vocal bird. Although known for its clap, it has many different calls. During mating season, you may hear it clapping or purring like a cat. When frightened, it can shriek or cluck like a chicken. If something is threatening its chicks, it may sound like a Great Horned Owl, with a low “oom” sound.

Like owls, Ridgway’s Rail regurgitate pellets. They are not picky eaters and eat seeds, grasses, spiders, worms, insects, small fish, and occasionally small birds. They hunt by seeing or smelling their prey, although they also use their long slender bills to probe shallow waters. Like gulls, Ridgway’s Rails can drink salt water since they have salt glands that desalinate the water.

Living in the mudflats, they spend significant time bathing.…