Western Bald Eagle Migration Update: April 21, 1999 Today's Report Includes: Today's Satellite Data from WESTERN Eagles One in a Thousand (or Two!) Today's Satellite Data from WESTERN Eagles Western Bald Eagle Migration as of 4/17/99 Here is the latest migration data: Eagle #12 Eagle #18 But as you track individual eagles by satellite this spring, don't forget: These individuals are not traveling alone. They actually represent of a wave of migratory movement. We asked Jim Watson's help in putting this into perspective. Here's what he had to say: One in a Thousand (or Two!) A Perspective on Tracking Migration by Satellite "Now that you have been following the western eagles for a few weeks, it might be interesting to reflect on the significance of these movements to the entire eagle population. After all, a biologist's job is to sample a population to learn more about the entire populations from which they come. Photo: USFWS "The 2 eagles you are tracking this spring are among an estimated 6,000 - 10,000 eagles that winter in Washington, Oregon, and southern British Columbia and travel to the far north to nest. Based on our telemetry locations, we see that their tendency is to move a few hundred kilometers for 1 or 2 days, and then stay at a location for a couple of days before moving again. "Imagine for a moment that you are standing on the Fraser River at Lillooet, or at Powell River on the coast of British Columbia, on a clear but breezy morning in late March or early April. You look up down the river (or coast), and about 200 m above the ridge line you see 2 eagles flying headlong, with a rapid wingbeat, and they pass out of sight to the north. About 2 minutes later you see another eagle, 100 m higher, but on the same course as the other birds. Pretty soon, several more eagles have passed, and by noon you have counted 70 eagles from that one location, all moving northward to nesting areas! "While exact numbers are is certain, if we make a conservative estimate of 3,000 eagles flying past Lillooet between 15 March and 15 April, that's about 100 birds/day moving through the area! Of course, some days you would see just a few birds, depending on weather conditions and whether it was early or late in the season. On other days you would see more eagles. "Thus, when you plot the locations of our 'sample' population of telemetered eagles on a large map it looks like these birds are traveling alone, while in reality there are several hundred birds moving along with them back to nesting areas in Alaska, the Yukon, Northwest Territories, and British Columbia." The Next Bald Eagle Migration Update will Be Posted on May 5, 1999. Copyright 1999 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form