Mon 05 Mar 2012

As we approach the vernal equinox the sounds of night flying geese can be heard on those calm evening strolls.  And such it was last night as my wife and i took our Newfie out for her evening walk.

In Oregon, Turkey Vultures, Rufus Hummingbirds, first waders — all are showing up.  Local patches have changing avifauna composition — most noticeably with the ducks and geese.  Migration is gearing up. Trickles will be the norm but good conditions will see widespread night flights.  And such it was last night.

As you can see from the winds aloft (last image) there was only a moderate (25 knots) WNW wind over the northern part of Oregon last night.  Really not a problem or impediment to avian travel.

Density is not high by peak migration standards, but directionality is strongly South to North at speeds up to 40 knots. Birds!  This is the largest flight i’ve seen this season on the radar.  The Reflectivity loop doesn’t really show the exodus bloom but in the three Velocity images i captured this development shortly after 6 PM last night is clearly seen – no movement at 6, by 6:41 many birds are in the air and by 10 the radar is completely lit up.

It is much more dramatic seen in the loop feeds that can be found over at RAP.

A recent blog post by fellow Oregonian, Greg Gillson, over at Pacific NW Birder, brought to my attention a new project by the folks at Cornell and eBird: BirdCast.

They have posted their first forecast and resulting analysis here.  Pretty good stuff!  I’m not sure what attention the West Coast will get because, as Greg points out in his post, migration is not as dramatically episodic as it can be back east.  That and the fact that Cornell is actually located back east (along with it’s donor base i would suppose) i would expect an eastern bias to their forecasting. I hope i’m wrong on this account.  In any event i’ll keep an eye on their work and see if we can dovetail their information into this blog.

I found it interesting that they used a variety of listserves for ground proofing as well as their special access to eBird data.  Neither of which i found particularly useful last season.  But then i don’t have access to the eBird data like they do nor do i have a bevy of graduate research assistants to wade through available information.  So any insights anyone may have that provides ground proofing information is heartily welcomed.

I have just picked up where i left off which assumes a familiarity with tracking migration with radar.  I will probably not get into full swing here until later in the season.  I do have some saved radar images from the first of March i want to comment on.  So, if any of the images or analysis is confusing — check out the Video Primer page or leave a question in the comment section and i’ll do my best to clear things up.

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