Fri 11 May 2012 – PNW Migration Update

The high pressure ridge that is parked off the coast is keeping the winds out of the north.  However, they dropped below 10 knots by the time the birds were ready to head north last night.  The winds aloft were right at 10 knots in our area and picking up to the south and west.  Obviously this was encouragement enough.

Locally migration was moderate with some pulses of heavy movement early in the exodus.  Movement was heaviest on the east side of the valley and up the I5 corridor to our north.  East side birding should be best bets for a turnover of migrants today.  Sandy River is looking particularly enticing.  Also, on the local radar loop you can see significant movement up the coast north of Newport – just in case you’re headed that way.

In the field most chatter on the listserve was about the vagrant Black-throated Sparrows out at Troutagonia (Troutdale Airport).  There was a report for vanguard Bullock’s Orioles, Chats, House Wrens, and Buntings.  So the stage is filling in quite nicely.  Bird occurrence is probably more a reflection of the spotty nature of field reports than the actual presence of the birds.

The outlook for migration this weekend remains good.  The issue continues to be the NNW winds.  They are forecasted to stay under 10 knots today and dropping down to 5 knots by Sunday, but that can change as this high pressure churns.  The temperatures will be rising through the weekend making early morning birding quite pleasant.

Regionally we saw another heavy movement of birds in the Rogue Valley last night.  However, it was quite diminished in breadth and it looks like just a local shuffling.  There are some stronger winds, to the north, in the Roseburg area and it might have been enough to keep the birds bottled up in the south.  The Rogue River listserve was kind of quiet but migrant activity was reported.  The southern Willamette Valley shows no movement – but it is a radar black hole anyway.  To get any returns out of there the birds have to be flying pretty darn high to get picked up. We were able to pick up birds from Corvallis north.  With the heaviest returns around Salem, but still on the east side of the valley.

Last night the southern portion of the Pacific flyway had moderate migration with the occasional local pulses up to 25 dBZ.  Densities dropped off last night in the Central Valley, and many areas had no returns.  This can be seen on the National Composite as patches of blue from Fresno to Medford.  However the movement was exceptionally heavy in southern California.  San Diego had heavy returns all night.  Not all of those birds are headed our way but a significant portion of them are.

Nationally the major front has moved up and off the east coast and now the trailing WNW winds are pounding the Mid-Atlantic and Northeast.   The pattern we saw yesterday continues –  just shifted a bit further east.  Migrantion last night was densest up the Mississippi Flyway.  There are some pretty severe storms raking the Texas gulf coast.  Depending on the level of trans-gulf movement last night, that is a recipe for fallout conditions.

As always — For more detailed migration updates in other regions check:

Wisconsin and New Jersey – woodcreeper by David LaPuma
Michigan’s Upper Peninsula – The Northwoods BIRDAR by Max Henschell <- NEW!
New England – Tom Auer’s blog
Florida/SE – Badbirdz Reloaded by Angel and Mariel Abreu
PA/Ohio Valley – Nemesis Bird by Drew Weber
NW Ohio – Birding the Crane Creek by Kenn Kaufman
Arizona – Words About Birds by Tim Schreckengost <- NEW!
New Mexico – Albuquerque Birding by Matt O’Donnell <- NEW!
Pac NW – Birds Over Portland by Greg Haworth
Continental US – eBird BirdCast Forecast & Report by Team eBird

Also under NEXRAD Trackers in the sidebar to the right.