"I've got an interesting job for you," my boss said to me one day. "How would you feel about doing a one-day RTK survey of birds' nests on an uninhabited island in the Pacific Ocean near Half Moon Bay?"

"I've got an interesting job for you," my boss said to me one day in April 2004. "How would you feel about doing a one-day RTK survey of birds' nests on an uninhabited island in the Pacific Ocean near Half Moon Bay?" With visions of palm trees, sandy beaches and lush vegetation in my mind, I wondered what I had done to earn the privilege of such a prestigious job. I instantly agreed to do it. He informed me that my predecessor had done the job twice in the past, told me the work order number, and told me to research it and be ready to go when the client called. As one of the chief principals at a mid-sized surveying and engineering firm, one of my boss's primary responsibilities is to sell our company's services. His excellent abilities as a salesperson became evident to me later when I realized how eagerly I had accepted one of the more miserable surveying jobs I'd ever known.

Along with layers of guano and numerous swarming flies, the original control point nail was not found.

The Story of the Rock

Being relatively new to California, I was unaware that there are no notable islands anywhere near Half Moon Bay. When I pulled the project files and began researching the job, the size of this so-called island became obvious. I found a topographic map prepared from the previous survey in 2001-the whole thing fit, easily, on a 24 x 36 sheet of paper at a scale of 1"=2'. The name of the job on the project folder also gave me some insight into the project site: "Devil's Slide Rock." Rock, not island. And I noticed that the plot stamp along the side of the previous map showed that the AutoCAD drawing name was "GUANO-01.DWG." Guano, as in bird droppings.

Devil's Slide, a portion of California Highway 1 that wraps around Montara Mountain between Pacifica and Half Moon Bay, is about 20 miles south of San Francisco along the San Mateo coast. Devil's Slide Rock is located about 1⁄4 mile off the coast. While the rock appears rather insignificant to a passerby, it has historically been a primary breeding site for the common murre, a threatened shorebird. In 1986, an oil spill from a tanker killed thousands of birds, and the already depleted colony of murres disappeared completely from the rock. As part of a settlement in a lawsuit filed against the tanker company by state and federal government, funding was allocated to mitigate natural resource damages. As the common murre were the most affected species, much of the funding went toward their restoration, and the Common Murre Restoration Project was born.

The entire area of interest was a small flat area at the top of the rock where the murres nested-a small space for about six people, and we were all tied into one common safety line.

A Different Kind of Bird Watching

The Common Murre Restoration Project is a division of the U.S. Fish and Wildlife Service and the Don Edwards San Francisco Bay National Wildlife Refuge, whose purpose is to restore the murre population that once nested on Devil's Slide Rock. A technique called "social attraction" is used in the project. Murre decoys are set up on the rock along with a solar-powered speaker constantly playing murre calls. As part of the attempt to restore the murre population to the rock, it was decided that it would be beneficial to keep track of the exact nesting locations of the birds as they return to the rock to nest. The folks with the Common Murre Restoration Project called on our company, Bestor Engineers Inc. (Monterey, Calif.) to provide an accurate map of the rock and all its features in order to study the birds' micro-habitats and research factors that influence the murres' choices of nesting locations.

Throughout the breeding season, the murre project has a full-time staff whose job it is to sit on the shore across from the rock to observe the birds' nests during the summer, keeping track of the birds' activities as well as their nesting locations.

Once the birds had nested and left the rock, we were called in. It was time to find out what Devil's Slide Rock was all about.

The Journey to the Rock

At about 4:00 a.m. I awoke, got dressed and started loading gear into my truck. After loading the GPS gear I met up with the other members of the team. I drove up the coast with Bill Perry, GIS specialist for the Biological Resources Division, Western Ecological Research Center of the U.S. Geological Survey (Bill analyzed the data from the project) and one of the two spotters who would be spending the day near my GPS base and observing us on the rock. I was able to find a control point onshore near the rock that had been used in the previous survey without much difficulty.

When my predecessor first surveyed the rock in 2000, he used an RTK base station on the rock and set a control point. An autonomous GPS position was used as the base point of the survey. As I set up the base, the morning's first light began to show, and Bill pointed out the rock. I looked out to sea and scanned the waters for a small island and saw nothing of the sort. Then I followed Bill's glance downward and got my first real sense of the rock's scale. It was a very small scale. From where I stood, I had to look down almost toward the shore to see it, and the rock appeared not unlike any other large rock that you might see on any stretch of shoreline. It seemed impossibly small and too near the shore to have any significance to anyone.

After setting up the base station, we returned to the harbor to load our gear into two 14-foot boats and prepare for the 45-minute ride to the rock. All of our gear was loaded into dry bags, and everyone was provided with an insulated float coat that thankfully nobody had to use. On the way up the coast Gerry McChesney, a wildlife biologist for the Common Murre Restoration Project, pointed out that we were passing a popular surfing spot known as Mavericks where there are occasionally 30- to 50-foot waves in the winter. Fortunately there was nothing that dramatic as we passed by in our small boats.

We finally reached solid ground-a small piece of it anyway. Getting off the boat proved to be the most treacherous part of the job. The boat pulled up near Devil's Rock but not right against it as it was covered with sharp barnacles. There was also a swell of 4-5 feet. The rock was quite steep rearing out of the water, and there was only a small space to jump onto, and even that was guaranteed to be slippery. As one person stood on the bow of the boat, the driver tried to time an approach to the rock so that he came within a couple of feet of it just as the swell reached its highest point. At that point the person was to jump off and clamber to the rock as the boat backed away quickly to avoid rubbing the boat against the barnacles as the swell went out again. One at a time, each of the six of us made a leap of faith onto the rock, and then the gear was unloaded by throwing the bags to those on the rock, all in sync with the swell.

We then began our ascent up the rock. The entire area of interest was a small flat area at the top where the murres nested. The sides of the rock were too steep to climb safely without protection from falling, so workers of the murre project had previously installed anchors into the rock face and determined a best route to the top. We were all given climbing harnesses and helmets, and we each had to wait our turn to get on the rope. Gerry made the first trip up with the rope, belayed from below. Climbing was a bit difficult because of the layers of slippery guano. Once a few people made it to the top and were tethered into a safety line, they began hauling the gear up with a second rope. Finally, with the team and all the gear on the top of the rock, the actual surveying could begin! The whole process of unloading and climbing was very time-consuming, and by the time we were ready to work it was after 10:00 a.m.

Surveying the nesting locations of the murres was challenging. The project's bird watchers coordinated with workers on the rock as to where the birds had nested, marking them with spare decoys and then locating with GPS.

Logistics of Locating the Nests

I unpacked my GPS gear, a Trimble (Sunnyvale, Calif.) 5800 GPS System rover with a TSCe Survey Controller. I then attempted to locate the nail that was originally set as a control point to tie into as a check. It wasn't immediately visible so I tried to stake to it. After 10 minutes digging through the layers of guano, I came to the conclusion that the nail was gone. I knew from doing the stakeout that I was at least in the ballpark; that is, I had set up the base on the right point. And I was relieved that the receiver didn't indicate that my point was 50 feet in any direction, which would have been in the water. Throughout the day I tied to several features on the rock that we had previously located to use as checks once I brought the data back to the office.

I located all of the decoys that had been placed on the rock. I used three different description codes to differentiate between standing decoys, incubating decoys, and decoys that had fallen or been knocked over.

Shortly after we arrived, the flies began swarming us. At any given moment it seemed like at least 100 flies were on each of us. Between the flies and the acrid smell of guano, it wasn't an entirely pleasant place to be. Guano got over everything and our hands were covered with it from climbing the rock. Walking around proved difficult at times. The top of the rock was a small space for about six people; we were all tied into one common safety line, which meant if any of us wanted to walk past another, we would have to unclip from the line and clip back in on the other side of that person.

After locating the decoys I began surveying the nest locations. This was a tricky task as well, since the birds had left no physical evidence of where they had nested. Two people with the murre project who had spent the summer watching the rock sat onshore at their usual vantage points and coordinated with a third person on the rock to come to a consensus where each nest had been. They would position about 15 at a time, and mark each location with either a spare decoy or a bag of popcorn kernels. I would then locate them with GPS, and they would move on to the next bunch. Each nest site had been assigned a number during the nesting season, and I was told the numbers as I located them, adding them to the description codes. This was time-consuming, as there were nearly 250 nest sites.

One of the two spotters helped locate the nesting locations and kept an eye on the base station.

A Job "˜For the Birds'

Finally, while the others were hauling gear down the rock (by rope) to within throwing distance of the boat, I finished the survey by collecting additional topography of some rock ledges that were not previously surveyed. By the time I was done, much of the gear had already been lowered, and I was one of the last people to rappel down the rock to help load the boats. Getting everyone and all the gear off the rock and loaded into the boats again took quite a bit of time, and by the time we returned to the harbor it was beginning to get dark out. After we had unloaded the boats it was definitely late. I stopped for a bite to eat with the group at a restaurant in El Granada on my way out of town, and then wearily drove the two hours back to our office in Monterey. It had been a long day.

The office processing of the data proved to be nothing too difficult. The data was downloaded into Trimble Geomatics Office, the points then exported to AutoCAD and Land Desktop (Autodesk, San Rafael, Calif.). Blocks were added for all of the decoys and nest sites, and the additional topo points were added to a surface and new contours were created. All of the data was then converted into ArcView Shape files (ESRI, Redlands, Calif.), which were delivered to Bill Perry along with hard copies of the AutoCAD drawing.

Despite the guano, the flies, the cold and more guano, it was definitely one of the more interesting and exciting surveying jobs I have ever done. And although Devil's Slide Rock isn't the kind of place a person would choose to spend a day relaxing, I was still glad to be the one to do the survey-and take part in a little adventure.

Devil's Slide Rock now has a live murre web cam. Live streaming video is hosted by the National Audubon Society. Visit www.fws.gov/sfbayrefuges/murre/webcam.htm.