Once-common marine birds disappearing from our coast
Bird surveys like this and others done by plane are tracking a significant ecological shift in our region — a major decline in once-abundant marine birds. From white-winged scoters and surf scoters to long-tailed ducks, murres, loons and some seagulls, the number of everyday marine birds here has plummeted dramatically in recent decades.
Scoters are down more than 75 percent from what they were in the late 1970s. Murres have dropped even more. Western grebes have mostly vanished, falling from several hundred thousand birds to about 20,000.
The reasons often vary — from climate change and shoreline development to marine pollution and the rebound of predators such as bald eagles.
But several new studies now also link many dwindling marine bird populations to what they eat — especially herring, anchovies, sand lance and surf smelt, the tiny swimmers often dubbed forage fish.
The relationship between marine birds and slick, fatty forage fish is complex. Some birds are here year-round while others pass through for just a few months. Some birds key in solely on silvery herring while others can just as easily eat flounder.
Some forage-fish species, such as herring, are a fraction of what they once were. But little information exists about the health of other species.
But an exhaustive new analysis of bird diets and population trends found that marine birds relying exclusively on fish like herring were up to 16 times more likely to be in trouble than birds that ate nonschooling bottom-dwellers like sculpin.
(via The Seattle Times)