PNW Migration Update — Narrative

I haven’t been keeping meticulously close attention to migrant arrivals this year so I thought I would put together a checklist of the 40 spring migrants moving through or coming into the Northern Willamette Valley of Oregon.

Using the data I compiled last year from eBird I ordered the migrants using the frequency data from earliest to latest arrival. The eBird data can be found in the header banner under “eBird Frequency Data”. I didn’t use the earliest arrival, nor would I say I used the mean. It’s probably somewhere in between but a bit closer to the earliest arrival.

For the four species that also winter in the area (Hermit Thrush, Yellow-rumped, Towsend’s and Orange-Crowned Warblers ) I picked the date when the frequency data jumps indicating migrants are moving through.

For the three species that are detected at very low levels (Gray Flycatcher, Bank Swallow, and Red-eyed Vireo) I just picked a date, but not the earliest.

Since eBird frequency charts are blocked out in four segments per month they assign the data to the 1st, 8th, 15th, and the 22nd of each month. So that is how it is presented here. This is equivalent to thinking of arrivals occurring sometime during the 1st, 2nd, 3rd, or 4th week of the month.

Each species is designated by a six letter code to save space. These will be intuitively obvious to any regular field observer. Not everybody will be able to decipher these codes so here is a link to a listing of the codes. Enter the alpha code into your browser search function and it will show you the name of the species.

Below is the table with my recollections of this year’s arrivals for the Northern Willamette Valley:

Specie         Sig Freq

TRESWA     15-Feb          reported

TURVUL      1-Mar           reported

RUFHUM   8-Mar           reported

VIGRSW     8-Mar           reported

BARSWA    22-Mar         reported

ORCRWA    22-Mar         reported

CLISWA       1-Apr            reported

COMYEL     1-Apr            reported

NRWISW    1-Apr            reported

BTGYWA    8-Apr            reported

CHISPA          8-Apr            reported

HERTHR      8-Apr            reported

YERUWA    8-Apr            reported

CASVIR       15-Apr          reported

HAMFLY     15-Apr          ????

HOUWRE   15-Apr          reported

NASWAR    15-Apr          reported

PASLFL        15-Apr          reported

WILWAR     15-Apr          reported

BLHEGR      22-Apr          ????

DUSFLY       22-Apr          reported

GRAFLY       22-Apr          ????

HERWAR    22-Apr          reported

MACWAR  22-Apr          reported

PURMAR    22-Apr          reported

TOWWAR  22-Apr          reported

WARVIR     22-Apr          reported

WESTAN     22-Apr          ????

YELWAR      22-Apr          ????

BULORI       1-May           reported

LAZBUN      1-May           reported

OLSIFL         1-May           ????

SWATHR     1-May           ????

WESKIN      1-May           reported

WEWOPE   1-May           ????

BANSWA    8-May           reported

YEBRCH       8-May           ????

WILFLY        15-May        ????

REEYVI        1-Jun             ????

COMNIG    8-Jun             ????

So, we have twelve species that I can’t recall being reported in the Northern Willamette Valley – but I’ve not kept up with all of the reports. Nor have I kept a record of when each reported species was first reported.

27 April 2015 — PNW Migration Update

More Western Kingbirds, first Dusky Flycatcher and Bullock’s Oriole.  I’m sure i’ve missed something over the weekend.  I’m pretty sure a Western Wood Pewee has shown up in southern Oregon.  Anyway, weekends are hectic and with the sun rising earlier it’s tough to do much but get out in the field and tend to chores.

Last night was a bit unusual as a weak little rain cell moved through the area at the time of nocturnal bloom (1 hr after sunset).  So there is no big flight taking off.  Maybe a couple of opportunistic flocks that found a hole in the weather.  But then, after the cell moved through a significant flight takes place at around 1:00 AM (18:00 UTC).  I don’t think i’ve seen that before.  If i have i don’t remember it.  Have a look:

24 April 2015 — PNW Migration Update

Shorebirds continue to move through the area.  Found in those isolated spots with suitable habitat. I don’t think anything new, that hasn’t been mentioned earlier, has shown up in the area.  But i’ve been quite busy with other tasks and i may have missed something.

Take a look at the winds aloft plot and you can see a concentrated low has formed bringing cold air out of the Gulf of Alaska and turning the winds to a more favorable direction for northbound migrants.

Unfortunately there are associated rains and that always dampens determination.  But give a bird any break in the weather and they will take advantage of that.  I put in the HC plot today so it is easier to pick out the birds from the weather.  It looks like they had a few hours of flight before giving up for the night.

If you look again at the winds aloft plot one might surmise a continental scenario:  looking good for the Central Flyway, and not so good for the Atlantic.  So i put in a snapshot of the National Radar Composite to see if that is how it played out last night.

Winds Aloft Plot: Source

National Radar Composite: Source

22 Apr 2015 — Migration Update

As predicted yesterday the north winds kept migrants grounded last night.  It looks like these conditions may hang around for a while too.  I have a capture of the situation in today’s gallery.  But i encourage anyone looking to get a handle on atmospheric conditions to visit Cameron’s website here.

A few more reports for the Portland Area: Lazuli Bunting, Western Kingbird, Warbling Vireo, Nashville Warbler.

 

21 Apr 2015 — PNW Migration Update

Wow — it’s getting hard to keep up.  Western Kingbird, Willow Flycatcher, Lazuli Bunting, Solitary Sandpiper, Chipping Sparrow, Yellow-headed Blackbird, and probably some i am forgetting, are now in the Portland area.  Lots of these birds are setting new early arrival dates and it makes me wonder why they left their wintering grounds so early?

Anyway, another great night for nocturnal flight. Heavy migration was underway along the whole Pacific Flyway.  We have an advancing high pressure system and the leading edge north winds may put a damper on migration over the next couple of days.  It depends on how strong the winds are once they make landfall.  So i put a wind map in today’s gallery to visualize whats going on.

20 Apr 2015 — PNW Migration Update

Over the weekend there have been a few reports of MacGillivray’s, Wilson’s, Nashville and Hermit Warbler, somewhere in Oregon a Western Kingbird, the first report of a Cassin’s Vireo, and a few “Western” Flycatchers.  Shorebirds are beginning to build in numbers as they move through.

Out on Sauvie Island (where i spent my weekend) Sandhill Crane numbers are way down as are most waterfowl numbers.  I haven’t seen a Canvasback or Ruddy Duck for a few weeks now and Scaup and Bufflehead are hard to come by.  Double-crested Cormorants are gone, and a few A. White Pelicans are moving through — probably on their way to the recently established breeding colony on the lower Columbia.

Last night’s radar (KRTX) was lit up solid green.  The stable, calm weather as a new ridge establishes is providing a nice set of flight conditions and the birds are taking advantage. I threw in a loop of the Medford (KMAX) radar because it’s rare to see such density from this station.

Update: Warbling Vireo, Yellow Warbler, and Western Tanager have made it to the Willamette Valley.

17 Apr 2015 — PNW Migration Update

Yesterday the west side of Sauvie Island WMA opened — i was there at first light and did not take the time to post an update.  Just like the weekends.  Anyway, the migration that night was solid, but on the moderate side.

Unlike last night!  Green doughnut night with some returns in the heavy to extreme range.

Its getting hard to keep up with the migrant influx along the Pacific Flyway. In the Portland area: a whiff of Wilson’s Warbler, a hoard of House Wren, a pulse of Purple Martin, and a mote of MacGillivray’s  Warbler.

It looks like Paul has ironed out the kinks in the national composite radar archive.  So head over to take a look. The Mississippi Flyway, behind the front moving across the country, filled in nicely.  A Cuban invasion of neotrops hit Key West.  And the Pacific Flyway was lit up from San Diego to Seattle.

 

15 Apr 2015 — PNW Migration Update

We have an advancing ridge of high pressure and a retreating trough of low — always a dicey proposition for spring migrants headed north.  There was a bit of movement last night, but it was on the moderate side at best.

Best chatter on the Pacific Flyway listserves comes from the Central Valley where Lazuli Bunting was noted.  Also Yellow-headed Blackbird and Western Flycatcher have made it to the Portland area.

There was some excellent trans-Mexican Gulf migration conditions last night and the flight into Key West was spectacular.  But for some reason i can’t download the file.  Maybe Badbirdz will archive a loop today.

14 Apr 2015 — PNW Migration Update

The push of the cold front into the state, with its rain and westerly flows, pretty much shut down large scale migration last night.  So there’s really nothing to see on the radar except rain.

Cassin’s Vireo, Black-throated Gray Warbler, Vaux’s Swift, and Wilson’s Warbler — all now being reported in the Willamette Valley.  And just a bit further south in Josephine County are Western Kingbird, House Wren, Nashville Warbler and Bullock’s Oriole.

13 Apr 2015 — PNW Migration Update

Excellent conditions – clear skies and a bit of a tail wind – lots of birds moving up the Pacific Flyway.

Bank Swallows and Yellow-breasted Chats have made it into the San Diego Area.  Tanagers are up into the Central Valley.  And Hermit Warblers are moving through the Coast Range here in Oregon.

Mike Patterson, who writes the North Coast Diaries blog, has a great piece on phenolongical variation across Oregon’s differing ecoregions.  It’s here  — highly recommended.

It was another night where the large scale impact of weather on migration is clearly on display.  So i threw in a National Radar Composite and a map of the winds at 850 mb heights (roughly 1500 meters).

For commentary on the migration through New England check out Tom Auer’s Blog.  Also, today he has some information on a new radar product coming out of NOAA.  It’s a product they are calling “Bioscatter“.  My guess it is the same algorithm, or a clone, that derives the Hydrometeor Classification images found at the College of DuPage’s weather site, and that i highlight here at times when separating birds from rain.  I have added it to the sidebar under the Weather section.  You’ll have to figure out how to access it by navigating their product menu.