Jul 11 2011 -- Oct 31 2011 Murres and Bald Eagles in a ‘Conservation Collision’
Common Murres, gulls, bald eagleBy Bonnie Henderson.
Neal Maine of Gearhart spent much of June with his zoom lens focused on the rocks just off Chapman Point, at the north end of Cannon Beach. Every flat-ish rock, it seems, had common murres crowding it—more murres than he’d ever seen there, 5,000 or more. But murres—the most numerous nesting seabirds on the Oregon coast—were apparently not breeding at Chapman Point. They were just there, roosting. A call by Neal to Roy Lowe of Oregon Islands National Wildlife Refuge, who had the results of this year’s aerial seabird surveys, revealed that, consistent with the past couple of years, there were no breeding colonies of murres anywhere in Oregon north of Yaquina Head this year—not at Three Arch Rocks near Oceanside (historically a huge murre nesting site, the largest south of Alaska), not at Cape Meares, not anywhere on the North Coast.
Is it bald eagles? Plenty of those at Chapman Point this year as well—as many as nine in Neal’s viewfinder at once. The recent increase in bald eagle raids on Northwest seabird colonies has been well documented; it’s a natural result of the eagles’ population rebound following their crash, in the 1950s and ‘60s, due to widespread use of DDT and similar chemicals. These days, where you see murres you’re likely to see bald eagles. They snatch murres in flight and pluck them off rocks. An eagle merely soaring over a murre colony typically causes every adult bird there to take flight, leaving eggs and chicks vulnerable not only to the eagles but to crows, gulls and other opportunistic predators. The odd thing—for which Neal has no explanation—is that the murres at Chapman Point this year haven’t been so easily spooked. He watched as a soaring eagle prompted no more than one-third of the birds into flight. Was it because they weren’t nesting? Or have the murres changed as a result of eagle interactions?
Maine, a retired biology teacher-turned-photographer (not to mention a former Oregon Shores board member and founder of the North Coast Land Conservancy) and for decades a close observer of nature on the coast, urges caution in drawing easy conclusions about either the murres’ behavior or their shifting population dynamics. “I think it’s a much bigger question than ‘bad’ bald eagles,” he says. Ocean temperatures, the timing of seasonal upwellings offshore, and many other factors influence the murre population—factors that may play out over two or three decades. Humans tend to want to “find the villain and string him up,” he says, “but I’ve never known a wildlife question to have a simple answer to it.” Nature is by definition dynamic; a steady state is rare. Wildlife populations tend to be either on their way down or on their way up, he says, “and we don’t always know which it is.”
He isn’t losing sleep over the absence of breeding murres on the North Coast; he’s just happy to see so many murres at Chapman Point. They’re breeding somewhere, some years at least, and they’re long-lived birds. He’s also happy to see so many bald eagles after years of absence.
No good guy. No bad guy. So what are we supposed to do about the common murre-bald eagle “conservation collision”? Three things, Neal says: Habitat, habitat, habitat. Oregon is fortunate that every rock and pinnacle on our 362-mile coastline is protected as part of Oregon Islands National Wildlife Refuge. Next: protection of the ocean itself.
Read more about this phenomenon in “New world order,” an article that appeared in the March 1, 2010 issue of High Country News. Oregon Field Guide also ran a piece on the murre-bald eagle connection last spring.
Contact: Phillip Johnson, Executive Director, (503) 238-4450, or EMAIL