My post last night was rejected because I forgot and added the map as an?attachment?instead of the link to Photobucket. Since the sky is clear I added a picture of this afternoons activity to show you the difference. ?It is the link below?labeled?Day 1:30 PM. ??

There are lots of birds heading south tonight and I noticed something that I failed to see a couple of nights ago. ? If you look at the attachment you will see that there are a lot more birds in the green at the top than in the red which have passed the radar station at Ocean Shores. ?How come? ?What happened to the rest of the birds? ?

Not everybody out there is a shore bird. ?Two years ago I was on a cruise ship from Seattle headed to Astoria around Labor Day. ?At dawn we were off Cape Flattery at the entrance to the Strait of Juan de Fuca about equal distance from the US and Canadian sides when a little flock of Golden Crowned Kinglets, three Golden Crowned sparrows, and one Pacific Wren care aboard. ?The Kinglets fluttered around a fake palm trees on the aft deck for about 15 minutes looking for bugs and finding none went on their way. ?The Sparrows stayed with us all day and left sometime in the dark off the coast of Oregon. ?I don't know what happened to the little Wren because it stayed hidden. ?At the time I didn't understand what was going on but now I realize that they were crossing the strait migrating from their summer in Canada. ?At first light they came across this strange "island" a couple of miles from shore and dropped in to look for eats. ?

Over the western end of the strait the flock splits and a lot of the birds head east following the strait before turning south over Seattle taking the inside route I indicate with the arrow. ?You can't see the flock split on this picture because the Olympics block the coast radar and the strait looks empty to the east but they are there on the Seattle radar picture along with a lot of other birds that cross over further down the strait. ?So lots of the birds in the green are songbirds. ?You can use density of the radar returns to estimate numbers. ?So you would get your most accurate shorebird figures from the red section.?

Tonight I thought I would introduce air and ground speed into the picture. ?In the article cited below the USGS clocked shorebirds at 45 miles per hour in New England migration flocks and without finding anything specific to west coast birds I'll use that as a base. ?I'm also assuming that like most small birds they are flying close to the surface and when I check the surface winds on the coast (wunderground.com) tonight I find that they are from the south at 8 to 14 mph. ?So tonight the birds are using up more energy against a head wind on average of about 10 mph which we subtract from their air speed to?calculate?their speed over the ground. ?So the flock is heading south at a ground speed of about 30-35 mph while individual birds and species within the cloud may be traveling somewhat faster or slower. ?

Like airplanes, birds do vary their flight altitude to find the best winds. ?Large birds like ducks and geese have the ability to go a lot higher (and faster) and when tracking them the experts take "winds aloft" into account. ?You can get the winds aloft for Seattle in an easy to read format here:?http://www.usairnet.com/cgi-bin/Winds/Aloft.cgi?icao=SEA&hr=6?if you want to see what that looks like and think about it this fall when you are probably tracking waterfowl. ??(Tonight there is no advantage to going higher. ?The winds aloft are calm to 3000ft.)?

"Radar has provided some of our best estimates of ground speeds for migrating flocks.?Radar echoes identified as shorebirds migrating off the New England coast moved steadily about 45 miles per hour for several hours;?songbird echoes typically traveled around 30 miles per hour. Some birds appear to reduce flight speed in proportion to the degree of assistance from a tailwind, thus conserving energy."? ? ? ? ?
USGS-Migration of Birds?Flight Speed and Rate of Migration-http://www.npwrc.usgs.gov/resource/birds/migratio/speed.htm
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Ray Holden
Olympia, WA

Life is for the birds.
?
There are lots of birds heading south tonight and I noticed something that I failed to see a couple of nights ago. ? If you look at the attachment you will see that there are a lot more birds in the green at the top than in the red which have passed the radar station at Ocean Shores. ?How come? ?What happened to the rest of the birds? ?

Not everybody out there is a shore bird. ?Two years ago I was on a cruise ship from Seattle headed to Astoria around Labor Day. ?At dawn we were off Cape Flattery at the entrance to the Strait of Juan de Fuca about equal distance from the US and Canadian sides when a little flock of Golden Crowned Kinglets, three Golden Crowned sparrows, and one Pacific Wren care aboard. ?The Kinglets fluttered around a fake palm trees on the aft deck for about 15 minutes looking for bugs and finding none went on their way. ?The Sparrows stayed with us all day and left sometime in the dark off the coast of Oregon. ?I don't know what happened to the little Wren because it stayed hidden. ?At the time I didn't understand what was going on but now I realize that they were crossing the strait migrating from their summer in Canada. ?At first light they came across this strange "island" a couple of miles from shore and dropped in to look for eats. ?

Over the western end of the strait the flock splits and a lot of the birds head east following the strait before turning south over Seattle taking the inside route I indicate with the arrow. ?You can't see the flock split on this picture because the Olympics block the coast radar and the strait looks empty to the east but they are there on the Seattle radar picture along with a lot of other birds that cross over further down the strait. ?So lots of the birds in the green are songbirds. ?You can use density of the radar returns to estimate numbers. ?So you would get your most accurate shorebird figures from the red section. ?(Upon closer examination I found that I drew the arrow for the birds headed east over the mountains when it should have gone over the water and along the coast from Neah Bay down through Port Townsend with the turn to the south more over Seattle. ?At that point they spread out along the I-5 corridor toward Portland.) ? Some
birds may in fact fly over the mountains but they block the radar so we don't see those.)

Tonight I thought I would introduce air and ground speed into the picture. ?In the article cited below the USGS clocked shorebirds at 45 miles per hour in New England migration flocks and without finding anything specific to west coast birds I'll use that as a base. ?I'm also assuming that like most small birds they are flying close to the surface and when I check the surface winds on the coast (wunderground.com) tonight I find that they are from the south at 8 to 14 mph. ?So tonight the birds are using up more energy against a head wind on average of about 10 mph which we subtract from their air speed to?calculate?their speed over the ground. ?So the flock is heading south at a ground speed of about 30-35 mph while individual birds and species within the cloud may be traveling somewhat faster or slower. ?

Like airplanes, birds do vary their flight altitude to find the best winds. ?Large birds like ducks and geese have the ability to go a lot higher (and faster) and when tracking them the experts take "winds aloft" into account. ?You can get the winds aloft for Seattle in an easy to read format here:?http://www.usairnet.com/cgi-bin/Winds/Aloft.cgi?icao=SEA&hr=6?if you want to see what that looks like and think about it this fall when you are probably tracking waterfowl. ??(Tonight there is no advantage to going higher. ?The winds aloft are calm to 3000ft.)?

"Radar has provided some of our best estimates of ground speeds for migrating flocks.?Radar echoes identified as shorebirds migrating off the New England coast moved steadily about 45 miles per hour for several hours;?songbird echoes typically traveled around 30 miles per hour. Some birds appear to reduce flight speed in proportion to the degree of assistance from a tailwind, thus conserving energy."? ? ? ? ?
USGS-Migration of Birds?Flight Speed and Rate of Migration-http://www.npwrc.usgs.gov/resource/birds/migratio/speed.htm

Night: 1:30 AM ?http://s607.photobucket.com/albums/tt158/rayleeholden/

This afternoon you see a cloud of birds mostly milling around offshore represented by the green to the south then some red up north toward Forks. ?The tide is close to high right now and my guess is that this pattern represents birds drifting along the shore feeding from south to north which is the way the tide moves. ?High tide begins to the south and moves with time to the north. ?The birds milling off shore could include fishers like Caspian Terns and maybe some of the Sooty Shearwaters as well. ?At any rate you can quickly see the difference between this and a night's migration pattern. ?
Day:? 1:30 PM ??http://s607.photobucket.com/albums/tt158/rayleeholden/

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Ray Holden
Olympia, WA

Life is for the birds.