It's rained 10.6 inches since January 1 here on the Columbia River Estuary, the average is 3.8 inches. And being at the end of the line for one of the largest river systems in North America means we also eventually see most of the water dropped elsewhere in the region. We've got water to spare. Dikes are failing, roads are sliding, every cow pasture is full of water.
Yeah, it's an inconvenience. It does some interesting things to the wildlife, as well.
First and foremost, water in the cow pastures motivates the ducks and shorebirds to move out of the estuary and up into these temporary ponds. It's not surprising that the dabblers and grazers would move. The combination of pond-like protection and delicious greenery would be too good to pass up. But even diving species like Bufflehead and Hooded Mergansers move into the ponds, presumably to eat earthworms and insect larvae driven out of the ground by the high water. An angry ocean surf has driven Western Grebes, Harlequin Duck and Oldsquaw up into the Necanicum River.
Raptors shift around as well. Red-tailed Hawk numbers were unusually high during the relatively dry early part of December, but are now below normal probably because their rodent prey base has been adversely affected by the high water in all the pastures. Bald Eagles, on the other hand, focus on ducks and carrion in the winter and are staying at normal numbers. Snowy Owls at the South Jetty were focusing on Black Rats early on, then shifted to Red Phalaropes during the storm driven wreck of that species. The phalaropes appear to have moved on and it looks like a couple of the south jetty owls moved on, too. The others are apparently making a dietary shift to Bufflehead.
More difficult to explain, but quite possibly weather related is the behavioral shift in Townsend's Warblers. In most years, this species moves around with the large feeding flocks of chickadees and kinglets, way up in the tree canopy. There are a couple places where one can find high densities and nearly pure flocks of Townsend's Warblers in winter, but this year the unusually high numbers are coming to local feeders, particularly suet feeders. I saw a flock of 12 (plus a single Orange-crowned Warbler) coming to a feeder in Astoria that has not, historically, attracted this kind of action. Perhaps the warblers found the feeders during the cold snap of mid-December and figured - why leave? Perhaps the heavy rains have made foraging in conifer canopies less productive. It's a mystery.
Posted by mbalame at January 13, 2006 8:53 AM