|Watching out for a rare bird|
|Written by Betty Bezzerides|
|August 22, 2009 06:00 am|
If only all those junior high school English teachers could reappear to assign the ubiquitous essay, “How I Spent My Summer Vacation.” I’d know just what to write about.
Oystercatcher chicks stay close to their parents as they explore their environment – the rocky intertidal zone off the Oregon Coast.
I watched black oystercatchers.
The 15-inch shorebirds are a familiar sight at local rocky shores. With an all black body, oversized red bill and noisy “wheeep wheeep,” they look and sound distinctive.
My interest in the birds began in spring 2007 when a team of scientists presented a program and slide show at the Chetco Community Public Library. Elise Elliott-Smith, a researcher with the U.S. Geological Survey, explained the birds are an “indicator species.” The health of their population indicates the health of their coastal habitat.
There are about 10,000 black oystercatchers living along the Pacific Coast, most of them in Alaska. Roughly 350 live on the Oregon coast. Elliott-Smith, who collaborates with Liz Kelly of the U.S. Fish and Wildlife Service, collects and analyzes data on the Oregon population. Is it growing, shrinking or staying the same? And what does that say about the health of our coastline?
The U.S. Fish and Wildlife Service has designated the birds a “Species of Concern” because their population is relatively small and near-shore habitat is often threatened by predators and coastal development.
Volunteers began counting the Oregon birds in 2005 and Elliott-Smith reported so far, numbers appear to be stable. She added volunteers also have been collecting reproductive data and asked for more help.
It sounded like the perfect job for someone who enjoys birds, is a sucker for detail and looks for every excuse to spend time watching the ocean.
A year went by before I e-mailed Elliott-Smith. I saw oystercatchers all the time on Mill Beach and asked her if anyone was monitoring that area.
Before long, Neil Holcomb called, asking, “When can you show me where these birds are?” Neil was a summer field assistant and volunteer coordinator. He’d been monitoring beaches in the Chetco Point area and was especially interested in north Mill Beach, often accessible only at low tide.
Bedecked with binoculars and spotting scope, we hiked past Zwagg’s Island to north Mill Beach on a windy day in mid-May. As if on cue, the familiar “wheeep wheeep” we were hoping for sounded from one of the near shore rocks.
Holcomb watched eagerly. “It looks like there’s a nest up there. I saw a definite incubation exchange,” he said. I began to realize that, like most subjects, avian biology has its own vocabulary. Holcomb explained that both male and female oystercatchers incubate eggs. An exchange occurs when one nesting adult of the pair trades places with the other.
“Let’s not bother them,” he said, stressing a cardinal rule for observers: Never disturb nesting birds.
We turned around and walked south on Mill Beach, which was, as birders like to say, “very birdy.” Barn swallows zinged overhead, while a squadron of brown pelicans fished in Macklyn Cove. At least half a dozen oystercatchers explored the rocks. “Probably adolescents,” Holcomb said, observing they appeared too flighty to be focused on nesting.
“There’s a nest on the Tanbark Cove side of Chetco Point,” he added. “Let’s take a look out there.”
I’ve walked the Chetco Point trail dozens of times, never realizing birds might be nesting nearby. Sure enough, an oystercatcher sat quietly in a niche on one of the big near-shore rocks. Holcomb named it “Iron Bolt Rock” for the large iron bolt and rust stains on its face.
That was it. I was hooked. The promise of seeing nesting birds and watching chicks develop was irresistible. I remembered my friend Judy Seyle lives near the north Mill Beach bluff and together we signed up to be observers.
While I turned into what my husband Ted called a “science grunt,” summer 2008 provided a crash course in nature’s harsh realities. Two chicks hatched on the rock near Judy’s bluff but disappeared when temperatures topped 100 degrees for several days in July. Holcomb, who by now had become our mentor in all things oystercatcher, explained that chicks are especially vulnerable when very young. They can’t regulate body temperature until three weeks old. Also, their small size and limited mobility may make them an easy target for predators.
The Iron Bolt pair tried twice but never produced chicks. Another pair nested on what we named “Picnic Rock” (so called because the best view is from the picnic table on the Chetco Point trail). Their chicks also likely succumbed to heat or predators or both.
Judy and I turned in our notes feeling glum. Black oystercatchers lay one to three eggs and usually raise one or two chicks to fledgling. “Our” survival rate was looking dismal but Neil told us not to be discouraged. “If every chick survived, we’d be overrun with oystercatchers,” he said philosophically.
Fast forward to this summer. “Could you help out again?” Elliott-Smith e-mailed. “We won’t have Neil this year, though,” she added, explaining his position had fallen to budget cuts.
Judy and I conferred. Without a trained field assistant, it seemed even more important to have experienced volunteer observers. Besides, we still wanted to watch an oystercatcher family develop from nest to fledge.
We told Elliott-Smith to count us in, agreeing to limit ourselves to Picnic Rock at Chetco Point and each visit the site once a week.
And so we began again.
The diary of an observer
May 16: It’s the first day of observation and I hardly know which way to look. To the south, an oystercatcher pair stick close together exploring Picnic Rock, while to the north a whale spouts in Macklyn Cove. I settle in for the usual 30-45 minute watch. Skies are clear, osprey chirp overhead and the fishing vessel Ina Ruth heads for port.
May 19: The pair is back and this time they’re rock tossing, a good sign they have nesting in mind. Oystercatchers don’t spend time on architectural niceties. Instead, they toss bits of gravel or shell around the “nest bowl” before settling down on virtually bare rock. Skies are clear again but it’s so windy I can hardly hold the binoculars steady.
May 28: Nest alert! One bird stands sentry on Picnic Rock while the other incubates. After 10 minutes, there’s an incubation exchange. In between looks through the binoculars I catch up on paperwork. A “Reproductive Data Form” must be completed for each visit, including oystercatcher behavior, weather conditions and any noteworthy activity at the site. A double-crested cormorant suns himself Dracula-style at one end of the rock but the nesters pay no attention.
June 5: Observed incubation exchange on Iron Bolt but nest appears to be in a crevice and nearly impossible to see. All seems calm with the pair at Picnic Rock. The birds incubate eggs for 26-32 days so I mark the calendar for a possible hatch date around June 19. Incubation exchange occurs again at Picnic and a beachcomber asks what I’m doing. She mentions seeing river otters on the beach and I explain they might be a danger for oystercatcher eggs and chicks. Other likely predators include crows, ravens, eagles and if the tide is low enough, raccoons and foxes.
June 16: Ted brings the spotting scope today for a closer look. We definitely see at least two eggs in the Picnic nest and a questionable exchange at Iron Bolt. The water is crowded with brown pelicans, murres, double-crested cormorants, osprey and even a belted kingfisher. Three fishing boats are working the cove and the dredge is at the mouth of the Chetco. I recall Neil Holcomb’s comment after last year’s nest failures: “This site may be too busy to support nesting birds.”
June 23: We have two chicks at Picnic Rock! Judy and I cluck as if we’d hatched them ourselves. They’re balls of black fluff about the size of baby chickens. The chicks are semi-precocial, which means they can walk shortly after hatching but rely on their parents to deliver food and keep them warm. Ours alternate between sheltering under a parent’s wings and scurrying along behind to explore their new world.
June 30: No activity on Iron Bolt, which makes us suspect the nest has failed, but the Picnic family has settled into a routine. One adult flies off, returns with food, the chicks gobble it up and then the second adult repeats the process. The birds’ diet includes intertidal invertebrates such as mussels, limpets, crabs and barnacles. So why are aren’t they called musselcatchers? The name came from Europe, where relatives of our birds do indeed feed on oysters.
July 5: It’s a bad day at Picnic Rock – cold wind, unrelenting fog and the chicks are nowhere in sight. It’s not uncommon for chicks to “go missing” at this age. They’re more active every day and may be exploring or resting on the backside of the rock or some other nook or cranny I can’t see, but still I’m worried. Yesterday there were Fourth of July fireworks in the cove. Was it too much commotion? Judy remembers Neil’s admonition not to name the chicks lest we get too attached and I recall my daughter-in-law’s story about her 4-H pigs. “No names,” her father ordered. “They’re Pig 1, Pig 2 and Pig 3.”
July 14: No chicks in sight but the adults are still present, so that’s a good sign. They keep their backs to me the whole time as if they’re watching the backside of the rock. It’s hatch time for other families, too. Three fuzzy western gull chicks forage low on Iron Bolt but no oystercatcher activity there.
July 19: Judy and I are relieved to see chicks and parents at Picnic today. “I can’t believe how big they are,” she e-mails, although we have no trouble distinguishing them from the adults. The chicks are still downy, lighter in color than the adults and their bills aren’t red yet. The feeding pattern has changed, though. Now the parents bring food to the rock and poke it in crevices for the chicks, who’ll fledge (be capable of flight) and forage on their own when they’re about 38-40 days old. I mark July 27 on the calendar as the first possible fledge date.
July 27: The family basks in the warm sun topside while an adult and baby river otter sunbathe closer to the water. Hopefully, the chicks are old enough for the otters to no longer be a threat. One of the chicks practices hopping and flapping its wings.
Aug. 2: All family members present and accounted for at Picnic Rock but no sign of chicks in flight. Another adult pair and one flapping chick are foraging low on Iron Bolt. “Where on earth did they come from?” Judy e-mails. We surmise they’re our elusive nesters and dub them “The Mystery Birds.”
Aug. 7: Judy types “Zip” in the subject of her e-mail, reporting not an oystercatcher to be seen anywhere. “We could be at the end?” she asks.
Aug. 9: No birds on either rock. It feels like here today, gone tomorrow and I’m certain the chicks have fledged. Oystercatchers often stay with the same mate for many years and may return to the same nest site, or one nearby. I update my notes at the picnic table, scan the water and wonder if I’ll see this pair again.