Rossmoor, a sprawling gated community on the outskirts of Walnut Creek, recently found itself entangled in an ecological controversy that spilled well beyond its manicured lawns and well-tended condos. At the heart of the issue are acorn woodpeckers that decided to turn some homes into storage facilities for acorns — granaries. We are not talking about one bird, or one home, or even one acorn, but a score of birds, tens of homes, and thousands of nuts. The issue was splashed across the headlines of local and national press when word got out that the federal government had given the go-ahead for a plan to kill the birds.
This local saga of acorn woodpeckers has featured outrage, politics, guns, bullets, and even poetry. But this story is really about the cost and the responsibility of living in a place where the urban meets the wild, or more precisely, where the suburban meets oak woodland.
To understand the conflict, I started in Colorado, of all places, where there wouldn’t be any acorn woodpeckers except for a truckload arriving from Rossmoor.
Bay Area Birds Studied… in Colorado
- Woodpeckers from Rossmoor were trapped and taken to this facility in Colorado for research on an unrelated project aimed at deterring the birds from using telephone poles as granary sites. Courtesy National Wildlife Research Center.
The glass, steel, and stone buildings are distinctively Colorado. The 43-acre U.S. Department of Agriculture National Wildlife Research Center facility is perched on a slight rise, with views of Fort Collins below. Behind the cluster of buildings are the beginnings of the foothills of the Rocky Mountains. If it weren’t for the security guard demanding to see identification and the austerity that accompanies federal research centers, this facility could pass for a sprawling finger of neighboring Colorado State University. But it’s not.
The main entrance of the National Wildlife Research Center feels like a museum replete with historical and interpretive information documenting the study of animals that have, one way or another, become a nuisance. Guided by the center’s spokesperson Gail Keirn through a maze of offices, cubicles, and buildings where the staff of 160 researchers work, I meet Scott Werner, a research wildlife biologist, and Shelagh Tupper, the biologist who is heading up the acorn woodpecker study.
We travel through another set of hallways and then into another room. We’re behind a panel of one-way glass, like in a detective show. On the other side of the glass is a two-story room with fluorescent lights that mimic sunshine. In the center of the room is a large cube net about the size of a semi-trailer. Inside the net are two eleven-foot posts that very much resemble telephone poles. But the poles, studded with different kinds of nuts, also look like some kind of bejeweled totem poles. Halfway up each pole is a wireless speaker. Between the two poles is a divine spread for a woodpecker: a dish of dry dog food, mixed nuts, a quarter of an orange, some grapes, mealworms, vitamin supplements, water, and — off to the side — a mounted roosting box. Perched on top of one of the poles is what I’ve come to see, a female acorn woodpecker from the wilds of Walnut Creek.
The trapping and transport of birds from Rossmoor is just one facet of a larger controversy.
The birds at the National Wildlife Research Center are not being studied to alleviate the problem at Rossmoor, but instead are part of a project funded by SoCal Edison to figure out ways to curb the woodpecker’s destruction of millions of dollars worth of utility infrastructure a year. Unlike other species of woodpeckers, which are adept at excavating cavities, acorn woodpeckers have instead developed traits that make them excellent aerial hunters of insects. With large wings and a beak designed for grabbing insects out of the air, the acorn woodpecker is not as well suited to searching for insects in the bark of trees. Nonetheless, the woodpeckers do use snags or dead limbs to store acorns for winter food supplies. Since they are not the strongest borers, they’ve evolved a keen ability to find the easiest places to create holes: a hollow-sounding substance with a hard surface and a soft substrate — such as the walls at Rossmoor, or SoCal Edison’s utility poles.
Tupper explains that the current study is just one of many that the National Wildlife Research Center has been doing for the utility industry since the late 1990s to figure out a good deterrent for the woodpeckers. Past iterations of the study have looked at the effectiveness of mechanical and sound devices to scare the birds away from the utility poles. Most sound deterrent systems on the market play a continuous loop of noises, or play them sporadically, and target a range of species from woodpeckers to pigeons. This study is different, Tupper says, and specifically targets acorn woodpeckers. “The device detects when the birds are pecking, so they are only being deterred when the birds are doing damage, so it’s not pre-programmed or preset in any way, which is the thing that we think is so cool about this technology,” says Tupper.
Researchers observe the birds for a week at a time and test three different deterrent noises, two natural predator sounds — the calls of sharp-shinned and Cooper’s hawks — and one acorn woodpecker distress call. Once the study is complete, Tupper will compile and publish the data, and then a private company will design a solar-powered, vibration-sensitive device that will be marketed to utility companies.
“We weren’t brought into Rossmoor to help solve the problem, our issue was with utility poles and we hope that what comes out of our study might somehow be part of a solution for Rossmoor,” says Tupper. Originally, the National Wildlife Research Center obtained a permit to trap the birds for the study on national forest land in California, where there are high densities of the species. When Tupper’s team learned that birds at Rossmoor were being hunted and killed under a U.S. Fish and Wildlife Service permit, they changed their own federal permit to capture birds that were considered a nuisance and slated to be exterminated anyway.
Of the 20 birds taken for the study, seven died after capture. Thirteen are now being studied in Fort Collins. If the birds are not used in another study, they will be killed when this one is done due to California rules that prohibit the release of birds that have been trapped and transported across state lines.
Back in California I had to pass through another security checkpoint, this time to get into the “active adult community” of Rossmoor. Rossmoor has gradually developed over the last 45 years. Currently, there are 6,700 homes with about 9,000 residents on 1,800 acres. In the heart of the valley a lush green golf course stands in stark contrast to the surrounding golden hills dotted with oaks.
The physical setting of the community is idyllic, and it’s marketed as such. The environment is what you’d expect — giant, ancient oaks and acres of grassy hills. This is the urban-wildland interface, though you won’t see that term in a real estate brochure.
The woodpeckers have always had a presence at Rossmoor. Bill Friesen, the operations director for one of the affected Home Owners Associations, says woodpeckers would occasionally try to store acorns in a home, maybe in a chimney or a plumbing vent, or even in the eaves. But these were isolated incidents.
About 10 years ago, three new subdivisions were built at Rossmoor. Two of those are the areas now most affected by the woodpecker. The newer homes were built farther up one of the hillsides and deeper into Rossmoor-owned open space. The homes were built by developer Shea Homes using a method called an Exterior Finish Insulation System–stucco over foam. The problem is one of compounding cause and effect: first, increased encroachment into prime acorn woodpecker habitat and second, a method of construction that is just what this species of woodpecker looks for in a granary site — a hard, hollow-sounding surface with a soft substrate underneath. The woodpeckers soon discovered that the trim, particularly around the windows, is soft substrate under a hard surface, their favorite. So they started boring holes in that trim. Now the buildings look like someone has sprayed them with machine gun fire, somehow miraculously sparing the glass but leaving scores of nickel-sized holes all around.
- Woodpecker holes in the stucco and foam frames around windows at the gated community of Rossmoor. Photo by Daniel McGlynn.
The homeowners were concerned, even irate. Besides the incessant noise of the woodpeckers drilling holes each autumn, there was a worry about structural damage from moisture entering the houses. To date the Home Owners Associations (HOAs) have spent about $170,000 on repairs and patches to their houses, and more repairs and retrofits are planned.
The HOAs tried a number of different methods of deterring the birds, from hanging flashy Mylar ribbons from the roof, to netting, to more creative scare tactics like battery-operated dangling spiders and hooting owls. None, however, was effective at keeping the birds from drilling. There’s even a report of woodpeckers boring holes into the head of a decoy owl.
The Shooting Starts
By 2007, after trying numerous deterrents, the two banged-up HOAs decided to apply for a U.S. Fish and Wildlife Service (USFWS) depredation permit (depredation is a federal agency euphemism for killing wildlife). The initial permit granted by USFWS, based on a study carried out by the U.S. Department of Agriculture’s Wildlife Services, was for 20 birds. Fifteen were shot. The following year, a new permit for 50 birds (50 birds total, so subtract the 15 already killed) was granted by USFWS. Again Wildlife Services conducted population studies and replied, “if anyone deserves a permit, we do,” says Friesen, who handles the permitting process for Rossmoor. In 2008, seven more birds were killed. The permit expired in May 2009. May was also the month when 20 birds were captured for the National Wildlife Research Center’s study. The permit may have expired, but future killing of the birds remains on the table. “It’s not out of the picture. There are still 28 birds left on the permit,” Friesen says.
In the long term, however, it’s unclear that killing the birds will solve the problem, given their complicated social structure. Biologist Eric Walters has been researching acorn woodpeckers since the early 1990s and his work is part of a 40-year-old acorn woodpecker study at U.C.’s Hastings Reserve in Carmel Valley. An average group of birds being studied at Hastings has four or five individuals who create and maintain about 2,000 acorn holes. But groups can be as large as 15 to 20 birds and thus would require about 20,000 to 30,000 holes. Because of the intricacies of breeding behavior and territory, most woodpeckers inherit breeding turf and the granaries along with it. Creating thousands of holes takes a tremendous amount of time and energy, so birds not responsible for breeding, called helpers, often spend their time scouting for new granary sites. This can include abandoned or unused granaries. For the birds, finding these sites, says Walters, “is like finding a bank account with money in it.”
Walters cites another study done at Hastings in the 1980s when a group of birds was captured and removed from its territory. Twenty minutes later other woodpeckers were observed moving into the area and taking control of the granaries. The conclusion? If you remove the nuisance birds now, more will likely colonize the area. Acorn woodpeckers will travel up to five miles in a day to scout for new granary sites. For abatement to be successful, Walters argues, you would have to exterminate every acorn woodpecker within a five-mile radius.
Walters also takes issue with the population study done by Wildlife Services that justifies the various permits issues by USFWS. These studies are “a complete joke,” says Walters. The numbers are based on reported calls and sightings but when tallied up paint a picture of a population size 10 times more than the largest population ever recorded. It also rankles Walters, and Mount Diablo Audubon, that the birds captured for the National Wildlife Research Center’s study were taken in May, during peak egg and nesting season. “It doesn’t make any biological sense,” says Walters.
- An artificial granary installed at Rossmoor. The granaries are meant to lure the birds away from homes. Photo by Daniel McGlynn.
In fall 2008, in an effort to find a non-lethal solution, the two Rossmoor HOAs opened discussions with Mount Diablo Audubon, which in turn consulted with Walters. They suggested a comprehensive plan that involves retrofitting the buildings with a more impervious material as well as creating artificial granaries. Audubon, some of whose members live in Rossmoor, offered to do studies for granary sites and even build them for free. But as of late 2008 one of the HOAs wanted to continue the abatement process. Diana Granados, the point person for Audubon during the talks, says, “They wouldn’t agree to stop killing, and that was something we couldn’t support.” By early 2009 Mount Diablo Audubon ended its formal consulting relationship with Rossmoor.
Friesen has a different take on how the talks ended. “Some Audubon members wanted to take over and bring in people to construct granaries,” he says. But he says that wasn’t an option because of liability. When Audubon backed away because the HOAs wouldn’t agree to a moratorium on the shooting, Friesen says they sent him a letter saying “now the political arm of the Audubon will flex its muscle.”
This is about when the Rossmoor woodpeckers ascended into the media spotlight. Friesen started receiving emails from as far away as Germany, and the political muscle flexed all the way to the office of Congresswoman Ellen Tauscher, who became involved. In May 2009 the depredation permit expired and was not renewed.
The Wait Until Acorn Season
During the summer lull in the woodpeckers’ granary construction, everyone is taking a breath and preparing for the next acorn season, which is about to begin.
The HOAs are gradually adopting some of the measures suggested by the experts and conservation groups. Originally, “our attitude was pull the acorns out and patch the holes,” says Friesen. Now, it looks like there will be a more comprehensive approach. The HOAs are experimenting with two new materials to bolster their homes’ exteriors. One is a fortified cement and the other is a metal lath covered with mortar. If one of these methods works, it will be rolled out as part of a large retrofit that will be done along with regularly scheduled maintenance.
In June, the HOAs constructed six artificial granaries near the edge of the Rossmoor open space. Each granary is a 20-foot post with a 2×12 board mounted on top. The boards have coin-sized holes in them and are made of soft woods like cedar and spruce. These granaries, like the new exterior materials, are experiments; if they do their job of keeping birds away from the houses, more will be built. “We’ll put up as many as we can,” says Friesen. But the risk is that the other deterrent methods may not work and the new granaries will only attract more woodpeckers.
For the moment, though, everyone is just waiting to see how the birds respond. “Right now, there is a 50/50 optimistic view,” Friesen says.
Like this article?
Help Bay Nature tell more stories about nature in the Bay Area
Make a tax deductible donation to Bay Nature today!
Most recent in Stewardship
The Bay is healthier now than it has been at any time in the past 50 years. And that’s because people in this century decided to work together across disciplines and institutional boundaries to reverse the damage done over the previous two centuries.
Human History | Stewardship