|With September rolling along, the numbers of waterfowl returning for winter are starting to increase again in Tramp and Quartermaster Harbors. A hundred or so scoters have returned already in Tramp Harbor and I recently saw several flocks of Horned, Red-necked and Western Grebes there.
Western Grebes form large rafts of birds in Quartermaster Harbor every winter. They usually hang out in the middle of Quartermaster Harbor or out in the middle of Colvos Passage. Close-in looks at more than one or two are rare. Smaller groups might be seen along the ferry routes or along any of the shoreline areas from time to time. In the fog, their presence can only be told by the sound of their scratchy call reverberating in the mist.
In the mid 1990's, as much as eight to ten percent of the state's wintering population stayed in Quartermaster Harbor. The National Audubon Society designated the harbor as an Important Bird Area because of the over 5000 birds censused regularly there. Islander Dan Willsie spent years counting the birds using a consistent methodology. However, the Christmas Bird Count (CBC) shows a decline from over 1600 counted in the 1998-99 count to 272 for 2004-2005 in the Quartermaster Harbor section of the Vashon count circle.
Meanwhile, Washington Department of Fish and Wildlife (WDFW) studies depict a significant decrease in marine birds of many species in the Puget Sound over the last 20 years. Western Grebes in the northern sub-region of Puget Sound show a 95% decline. The cause for the decline remains unexplained. Speculation as to the reasons range from disturbances to the birds and their habitat on the breeding grounds to declines in key prey populations such as herring.
Numbers for the Western Grebe in WDFW research originally held stable for the central Puget Sound area around Bainbridge and Vashon Island. But the decline evidenced by Vashon CBC figures for the last several years indicate that these areas begin to match the similar reduction in population seen in the northern region of Puget Sound. Studies by WDFW involving the Quartermaster Harbor Pacific Herring stock describe a peak in numbers in 1995 followed by a decrease through 2004. As the fall in Western Grebe counts parallels that with herring, there may be a strong correlation between the two.