December 2, 2008
Pelicans
I am beginning my 21st winter here on the lower Columbia River. When I first moved here we had pelicans. They'd arrive from their breeding grounds in late May. The numbers would peak sometime in August. And by the first winter storms of November, they'd be gone. Finding one or two lingering into December was considered a rare event.
Today I saw close to 500 at the South Jetty of the Columbia.
Brown Pelicans were one of several species that saw precipitous population declines caused by the effects of DDT and other pollutants in the 1950's and 60's. They were one of the first species to be listed and protected by the Endangered Species Act. Populations along the Pacific Coast responded well and numbers increased remarkably. Recent population studies put the number of Brown Pelicans that summer along the Oregon Coast at over 10,000 and the majority of these can be found foraging at the mouth of the Columbia River. There have even been observations of breeding behaviors among birds that arrive at East Sand Island in April. If birds do begin breeding here, they will represent the northern most breeding colony on the West Coast, the next closest being at the Channel Islands, 1000 miles to the south.
Winter pelicans started turning up more frequently beginning around 2000. Usually just one or two storm stressed stragglers. They were a bit more common farther down the coast toward Coos Bay, but still never more than 20 at any given location. This season has been very different with 100's of pelicans still being reported all along the coast. The numbers at the Columbia River are comparable to numbers we might see in September. It is unprecedented.
Equally, remarkable are the lingering Heerman's Gulls which follow pelicans while they're feeding and steal fish from them. Heerman's Gulls usually arrive later than pelicans in the spring and leave before them in the fall.
So, what's going on? Why haven't the pelicans gone south? I don't know. Maybe we just haven't had a strong enough winter storm set to send them south. Maybe there's something going on with the fish, that's keeping them here. Maybe they're just happy about the outcome of the recent elections.
It's hard to make any concrete claims about the cause of any single event. If the pelicans continue to linger in the following seasons; if they start laying eggs on East Sand Island; if we start hearing reports of winter pelicans in Juneau, then, maybe, we can start framing a working hypothesis...
Posted by mbalame at December 2, 2008 4:13 PM