[Tweeters] Snowy Owl Irruptions

notcalm at comcast.net notcalm at comcast.net
Tue Dec 3 12:51:02 PST 2013

Very interesting and useful graphics of past Snowy Owl irruptions in North American , Josh.

Thanks for sharing it.

Dan Reiff
Mercer Island

----- Original Message -----
From: "Josh Adams" < xjoshx @ gmail .com>
To: "Tweeters" <tweeters at u. washington . edu >
Sent: Tuesday, December 3, 2013 12:03:19 PM
Subject: [Tweeters] Snowy Owl Irruptions

Hello Tweets,
I've seen a few posts referencing Snowy Owl irruptions on the east coast along with optimism that this might indicate a third consecutive year of irruption here on the west coast. I'm not an expert on the subject by any means, but I've done enough reading in the Tweeters archives to play "weather man." Despite a couple of recent sighting reports in Western Washington, I believe we are well past the window when we should start seeing Snowy Owls in any sort of significant irruptive year. In the three major irruptive years I found (2005, 2011, and 2012), the owls consistently started showing up in Western Washington in the second week of November.

Here were the dates of the first Western Washington reports I could find in the Tweeters archives:
November 17 2005 - Birdbox report of Snowy Owl in Everett. Many sightings after that.

November 13th 2011 - Snowy Owl in Ocean Shores. Within a week they were appearing in many locations.

November 9th 2012 - Bud Anderson reports a Snowy Owl seen at Sea-Tac airport, Two days later at least one Snowy made an appearance in Seattle and sightings only increased from there.

On several occasions, we received a day or two advanced notice of birds showing up in BC which could indicate an irruption year.

As you well know, we are well past the second week of November when the owls should have started showing up. We certainly may (and apparently do) have owls that will show up in western Washington, but nothing like either of the last two years. The last two years have been incredible, and may end up being the best two year stretch of Snowy Owl sightings in our lifetimes.

This year looks to be similar to the winter of 2008-2009, where the owls irrupted in good numbers in the east, but not at all in the west.

For fun I made an animation of ebird sightings of the last 8 years of Snowy Owl sightings in November across all of North America. I probably should have kept going and added 2005 as well, but knowing that eBird has much less data the farther back you go I didn't want to skew the results too much.

Here is a link to the animation:
http ://i. imgur .com/93OEG6K. gif

Josh Adams
Lynnwood , WA
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